[PATCH 4.14 082/167] kmemcheck: rip it out

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Levin, Alexander (Sasha Levin) <alexander.levin@xxxxxxxxxxx>

commit 4675ff05de2d76d167336b368bd07f3fef6ed5a6 upstream.

Fix up makefiles, remove references, and git rm kmemcheck.

Link: http://lkml.kernel.org/r/20171007030159.22241-4-alexander.levin@xxxxxxxxxxx
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Vegard Nossum <vegardno@xxxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Tim Hansen <devtimhansen@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 Documentation/admin-guide/kernel-parameters.txt |    7 
 Documentation/dev-tools/index.rst               |    1 
 Documentation/dev-tools/kmemcheck.rst           |  733 ------------------------
 MAINTAINERS                                     |   10 
 arch/x86/Kconfig                                |    3 
 arch/x86/include/asm/kmemcheck.h                |   42 -
 arch/x86/include/asm/string_32.h                |    9 
 arch/x86/include/asm/string_64.h                |    8 
 arch/x86/kernel/cpu/intel.c                     |   15 
 arch/x86/mm/Makefile                            |    2 
 arch/x86/mm/init.c                              |    5 
 arch/x86/mm/kmemcheck/Makefile                  |    1 
 arch/x86/mm/kmemcheck/error.c                   |  227 -------
 arch/x86/mm/kmemcheck/error.h                   |   15 
 arch/x86/mm/kmemcheck/kmemcheck.c               |  658 ---------------------
 arch/x86/mm/kmemcheck/opcode.c                  |  106 ---
 arch/x86/mm/kmemcheck/opcode.h                  |    9 
 arch/x86/mm/kmemcheck/pte.c                     |   22 
 arch/x86/mm/kmemcheck/pte.h                     |   10 
 arch/x86/mm/kmemcheck/selftest.c                |   70 --
 arch/x86/mm/kmemcheck/selftest.h                |    6 
 arch/x86/mm/kmemcheck/shadow.c                  |  173 -----
 arch/x86/mm/kmemcheck/shadow.h                  |   18 
 include/linux/interrupt.h                       |   15 
 include/linux/kmemcheck.h                       |  171 -----
 kernel/softirq.c                                |   10 
 kernel/sysctl.c                                 |   10 
 lib/Kconfig.debug                               |    6 
 lib/Kconfig.kmemcheck                           |   94 ---
 mm/Kconfig.debug                                |    1 
 mm/Makefile                                     |    2 
 mm/kmemcheck.c                                  |  125 ----
 mm/slub.c                                       |    5 
 scripts/kernel-doc                              |    2 
 tools/include/linux/kmemcheck.h                 |    8 
 35 files changed, 7 insertions(+), 2592 deletions(-)

--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1841,13 +1841,6 @@
 			Built with CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF=y,
 			the default is off.
 
-	kmemcheck=	[X86] Boot-time kmemcheck enable/disable/one-shot mode
-			Valid arguments: 0, 1, 2
-			kmemcheck=0 (disabled)
-			kmemcheck=1 (enabled)
-			kmemcheck=2 (one-shot mode)
-			Default: 2 (one-shot mode)
-
 	kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
 			Default is 0 (don't ignore, but inject #GP)
 
--- a/Documentation/dev-tools/index.rst
+++ b/Documentation/dev-tools/index.rst
@@ -21,7 +21,6 @@ whole; patches welcome!
    kasan
    ubsan
    kmemleak
-   kmemcheck
    gdb-kernel-debugging
    kgdb
    kselftest
--- a/Documentation/dev-tools/kmemcheck.rst
+++ /dev/null
@@ -1,733 +0,0 @@
-Getting started with kmemcheck
-==============================
-
-Vegard Nossum <vegardno@xxxxxxxxxx>
-
-
-Introduction
-------------
-
-kmemcheck is a debugging feature for the Linux Kernel. More specifically, it
-is a dynamic checker that detects and warns about some uses of uninitialized
-memory.
-
-Userspace programmers might be familiar with Valgrind's memcheck. The main
-difference between memcheck and kmemcheck is that memcheck works for userspace
-programs only, and kmemcheck works for the kernel only. The implementations
-are of course vastly different. Because of this, kmemcheck is not as accurate
-as memcheck, but it turns out to be good enough in practice to discover real
-programmer errors that the compiler is not able to find through static
-analysis.
-
-Enabling kmemcheck on a kernel will probably slow it down to the extent that
-the machine will not be usable for normal workloads such as e.g. an
-interactive desktop. kmemcheck will also cause the kernel to use about twice
-as much memory as normal. For this reason, kmemcheck is strictly a debugging
-feature.
-
-
-Downloading
------------
-
-As of version 2.6.31-rc1, kmemcheck is included in the mainline kernel.
-
-
-Configuring and compiling
--------------------------
-
-kmemcheck only works for the x86 (both 32- and 64-bit) platform. A number of
-configuration variables must have specific settings in order for the kmemcheck
-menu to even appear in "menuconfig". These are:
-
-- ``CONFIG_CC_OPTIMIZE_FOR_SIZE=n``
-	This option is located under "General setup" / "Optimize for size".
-
-	Without this, gcc will use certain optimizations that usually lead to
-	false positive warnings from kmemcheck. An example of this is a 16-bit
-	field in a struct, where gcc may load 32 bits, then discard the upper
-	16 bits. kmemcheck sees only the 32-bit load, and may trigger a
-	warning for the upper 16 bits (if they're uninitialized).
-
-- ``CONFIG_SLAB=y`` or ``CONFIG_SLUB=y``
-	This option is located under "General setup" / "Choose SLAB
-	allocator".
-
-- ``CONFIG_FUNCTION_TRACER=n``
-	This option is located under "Kernel hacking" / "Tracers" / "Kernel
-	Function Tracer"
-
-	When function tracing is compiled in, gcc emits a call to another
-	function at the beginning of every function. This means that when the
-	page fault handler is called, the ftrace framework will be called
-	before kmemcheck has had a chance to handle the fault. If ftrace then
-	modifies memory that was tracked by kmemcheck, the result is an
-	endless recursive page fault.
-
-- ``CONFIG_DEBUG_PAGEALLOC=n``
-	This option is located under "Kernel hacking" / "Memory Debugging"
-	/ "Debug page memory allocations".
-
-In addition, I highly recommend turning on ``CONFIG_DEBUG_INFO=y``. This is also
-located under "Kernel hacking". With this, you will be able to get line number
-information from the kmemcheck warnings, which is extremely valuable in
-debugging a problem. This option is not mandatory, however, because it slows
-down the compilation process and produces a much bigger kernel image.
-
-Now the kmemcheck menu should be visible (under "Kernel hacking" / "Memory
-Debugging" / "kmemcheck: trap use of uninitialized memory"). Here follows
-a description of the kmemcheck configuration variables:
-
-- ``CONFIG_KMEMCHECK``
-	This must be enabled in order to use kmemcheck at all...
-
-- ``CONFIG_KMEMCHECK_``[``DISABLED`` | ``ENABLED`` | ``ONESHOT``]``_BY_DEFAULT``
-	This option controls the status of kmemcheck at boot-time. "Enabled"
-	will enable kmemcheck right from the start, "disabled" will boot the
-	kernel as normal (but with the kmemcheck code compiled in, so it can
-	be enabled at run-time after the kernel has booted), and "one-shot" is
-	a special mode which will turn kmemcheck off automatically after
-	detecting the first use of uninitialized memory.
-
-	If you are using kmemcheck to actively debug a problem, then you
-	probably want to choose "enabled" here.
-
-	The one-shot mode is mostly useful in automated test setups because it
-	can prevent floods of warnings and increase the chances of the machine
-	surviving in case something is really wrong. In other cases, the one-
-	shot mode could actually be counter-productive because it would turn
-	itself off at the very first error -- in the case of a false positive
-	too -- and this would come in the way of debugging the specific
-	problem you were interested in.
-
-	If you would like to use your kernel as normal, but with a chance to
-	enable kmemcheck in case of some problem, it might be a good idea to
-	choose "disabled" here. When kmemcheck is disabled, most of the run-
-	time overhead is not incurred, and the kernel will be almost as fast
-	as normal.
-
-- ``CONFIG_KMEMCHECK_QUEUE_SIZE``
-	Select the maximum number of error reports to store in an internal
-	(fixed-size) buffer. Since errors can occur virtually anywhere and in
-	any context, we need a temporary storage area which is guaranteed not
-	to generate any other page faults when accessed. The queue will be
-	emptied as soon as a tasklet may be scheduled. If the queue is full,
-	new error reports will be lost.
-
-	The default value of 64 is probably fine. If some code produces more
-	than 64 errors within an irqs-off section, then the code is likely to
-	produce many, many more, too, and these additional reports seldom give
-	any more information (the first report is usually the most valuable
-	anyway).
-
-	This number might have to be adjusted if you are not using serial
-	console or similar to capture the kernel log. If you are using the
-	"dmesg" command to save the log, then getting a lot of kmemcheck
-	warnings might overflow the kernel log itself, and the earlier reports
-	will get lost in that way instead. Try setting this to 10 or so on
-	such a setup.
-
-- ``CONFIG_KMEMCHECK_SHADOW_COPY_SHIFT``
-	Select the number of shadow bytes to save along with each entry of the
-	error-report queue. These bytes indicate what parts of an allocation
-	are initialized, uninitialized, etc. and will be displayed when an
-	error is detected to help the debugging of a particular problem.
-
-	The number entered here is actually the logarithm of the number of
-	bytes that will be saved. So if you pick for example 5 here, kmemcheck
-	will save 2^5 = 32 bytes.
-
-	The default value should be fine for debugging most problems. It also
-	fits nicely within 80 columns.
-
-- ``CONFIG_KMEMCHECK_PARTIAL_OK``
-	This option (when enabled) works around certain GCC optimizations that
-	produce 32-bit reads from 16-bit variables where the upper 16 bits are
-	thrown away afterwards.
-
-	The default value (enabled) is recommended. This may of course hide
-	some real errors, but disabling it would probably produce a lot of
-	false positives.
-
-- ``CONFIG_KMEMCHECK_BITOPS_OK``
-	This option silences warnings that would be generated for bit-field
-	accesses where not all the bits are initialized at the same time. This
-	may also hide some real bugs.
-
-	This option is probably obsolete, or it should be replaced with
-	the kmemcheck-/bitfield-annotations for the code in question. The
-	default value is therefore fine.
-
-Now compile the kernel as usual.
-
-
-How to use
-----------
-
-Booting
-~~~~~~~
-
-First some information about the command-line options. There is only one
-option specific to kmemcheck, and this is called "kmemcheck". It can be used
-to override the default mode as chosen by the ``CONFIG_KMEMCHECK_*_BY_DEFAULT``
-option. Its possible settings are:
-
-- ``kmemcheck=0`` (disabled)
-- ``kmemcheck=1`` (enabled)
-- ``kmemcheck=2`` (one-shot mode)
-
-If SLUB debugging has been enabled in the kernel, it may take precedence over
-kmemcheck in such a way that the slab caches which are under SLUB debugging
-will not be tracked by kmemcheck. In order to ensure that this doesn't happen
-(even though it shouldn't by default), use SLUB's boot option ``slub_debug``,
-like this: ``slub_debug=-``
-
-In fact, this option may also be used for fine-grained control over SLUB vs.
-kmemcheck. For example, if the command line includes
-``kmemcheck=1 slub_debug=,dentry``, then SLUB debugging will be used only
-for the "dentry" slab cache, and with kmemcheck tracking all the other
-caches. This is advanced usage, however, and is not generally recommended.
-
-
-Run-time enable/disable
-~~~~~~~~~~~~~~~~~~~~~~~
-
-When the kernel has booted, it is possible to enable or disable kmemcheck at
-run-time. WARNING: This feature is still experimental and may cause false
-positive warnings to appear. Therefore, try not to use this. If you find that
-it doesn't work properly (e.g. you see an unreasonable amount of warnings), I
-will be happy to take bug reports.
-
-Use the file ``/proc/sys/kernel/kmemcheck`` for this purpose, e.g.::
-
-	$ echo 0 > /proc/sys/kernel/kmemcheck # disables kmemcheck
-
-The numbers are the same as for the ``kmemcheck=`` command-line option.
-
-
-Debugging
-~~~~~~~~~
-
-A typical report will look something like this::
-
-    WARNING: kmemcheck: Caught 32-bit read from uninitialized memory (ffff88003e4a2024)
-    80000000000000000000000000000000000000000088ffff0000000000000000
-     i i i i u u u u i i i i i i i i u u u u u u u u u u u u u u u u
-             ^
-
-    Pid: 1856, comm: ntpdate Not tainted 2.6.29-rc5 #264 945P-A
-    RIP: 0010:[<ffffffff8104ede8>]  [<ffffffff8104ede8>] __dequeue_signal+0xc8/0x190
-    RSP: 0018:ffff88003cdf7d98  EFLAGS: 00210002
-    RAX: 0000000000000030 RBX: ffff88003d4ea968 RCX: 0000000000000009
-    RDX: ffff88003e5d6018 RSI: ffff88003e5d6024 RDI: ffff88003cdf7e84
-    RBP: ffff88003cdf7db8 R08: ffff88003e5d6000 R09: 0000000000000000
-    R10: 0000000000000080 R11: 0000000000000000 R12: 000000000000000e
-    R13: ffff88003cdf7e78 R14: ffff88003d530710 R15: ffff88003d5a98c8
-    FS:  0000000000000000(0000) GS:ffff880001982000(0063) knlGS:00000
-    CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
-    CR2: ffff88003f806ea0 CR3: 000000003c036000 CR4: 00000000000006a0
-    DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
-    DR3: 0000000000000000 DR6: 00000000ffff4ff0 DR7: 0000000000000400
-     [<ffffffff8104f04e>] dequeue_signal+0x8e/0x170
-     [<ffffffff81050bd8>] get_signal_to_deliver+0x98/0x390
-     [<ffffffff8100b87d>] do_notify_resume+0xad/0x7d0
-     [<ffffffff8100c7b5>] int_signal+0x12/0x17
-     [<ffffffffffffffff>] 0xffffffffffffffff
-
-The single most valuable information in this report is the RIP (or EIP on 32-
-bit) value. This will help us pinpoint exactly which instruction that caused
-the warning.
-
-If your kernel was compiled with ``CONFIG_DEBUG_INFO=y``, then all we have to do
-is give this address to the addr2line program, like this::
-
-	$ addr2line -e vmlinux -i ffffffff8104ede8
-	arch/x86/include/asm/string_64.h:12
-	include/asm-generic/siginfo.h:287
-	kernel/signal.c:380
-	kernel/signal.c:410
-
-The "``-e vmlinux``" tells addr2line which file to look in. **IMPORTANT:**
-This must be the vmlinux of the kernel that produced the warning in the
-first place! If not, the line number information will almost certainly be
-wrong.
-
-The "``-i``" tells addr2line to also print the line numbers of inlined
-functions.  In this case, the flag was very important, because otherwise,
-it would only have printed the first line, which is just a call to
-``memcpy()``, which could be called from a thousand places in the kernel, and
-is therefore not very useful.  These inlined functions would not show up in
-the stack trace above, simply because the kernel doesn't load the extra
-debugging information. This technique can of course be used with ordinary
-kernel oopses as well.
-
-In this case, it's the caller of ``memcpy()`` that is interesting, and it can be
-found in ``include/asm-generic/siginfo.h``, line 287::
-
-    281 static inline void copy_siginfo(struct siginfo *to, struct siginfo *from)
-    282 {
-    283         if (from->si_code < 0)
-    284                 memcpy(to, from, sizeof(*to));
-    285         else
-    286                 /* _sigchld is currently the largest know union member */
-    287                 memcpy(to, from, __ARCH_SI_PREAMBLE_SIZE + sizeof(from->_sifields._sigchld));
-    288 }
-
-Since this was a read (kmemcheck usually warns about reads only, though it can
-warn about writes to unallocated or freed memory as well), it was probably the
-"from" argument which contained some uninitialized bytes. Following the chain
-of calls, we move upwards to see where "from" was allocated or initialized,
-``kernel/signal.c``, line 380::
-
-    359 static void collect_signal(int sig, struct sigpending *list, siginfo_t *info)
-    360 {
-    ...
-    367         list_for_each_entry(q, &list->list, list) {
-    368                 if (q->info.si_signo == sig) {
-    369                         if (first)
-    370                                 goto still_pending;
-    371                         first = q;
-    ...
-    377         if (first) {
-    378 still_pending:
-    379                 list_del_init(&first->list);
-    380                 copy_siginfo(info, &first->info);
-    381                 __sigqueue_free(first);
-    ...
-    392         }
-    393 }
-
-Here, it is ``&first->info`` that is being passed on to ``copy_siginfo()``. The
-variable ``first`` was found on a list -- passed in as the second argument to
-``collect_signal()``. We  continue our journey through the stack, to figure out
-where the item on "list" was allocated or initialized. We move to line 410::
-
-    395 static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
-    396                         siginfo_t *info)
-    397 {
-    ...
-    410                 collect_signal(sig, pending, info);
-    ...
-    414 }
-
-Now we need to follow the ``pending`` pointer, since that is being passed on to
-``collect_signal()`` as ``list``. At this point, we've run out of lines from the
-"addr2line" output. Not to worry, we just paste the next addresses from the
-kmemcheck stack dump, i.e.::
-
-     [<ffffffff8104f04e>] dequeue_signal+0x8e/0x170
-     [<ffffffff81050bd8>] get_signal_to_deliver+0x98/0x390
-     [<ffffffff8100b87d>] do_notify_resume+0xad/0x7d0
-     [<ffffffff8100c7b5>] int_signal+0x12/0x17
-
-	$ addr2line -e vmlinux -i ffffffff8104f04e ffffffff81050bd8 \
-		ffffffff8100b87d ffffffff8100c7b5
-	kernel/signal.c:446
-	kernel/signal.c:1806
-	arch/x86/kernel/signal.c:805
-	arch/x86/kernel/signal.c:871
-	arch/x86/kernel/entry_64.S:694
-
-Remember that since these addresses were found on the stack and not as the
-RIP value, they actually point to the _next_ instruction (they are return
-addresses). This becomes obvious when we look at the code for line 446::
-
-    422 int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
-    423 {
-    ...
-    431                 signr = __dequeue_signal(&tsk->signal->shared_pending,
-    432						 mask, info);
-    433			/*
-    434			 * itimer signal ?
-    435			 *
-    436			 * itimers are process shared and we restart periodic
-    437			 * itimers in the signal delivery path to prevent DoS
-    438			 * attacks in the high resolution timer case. This is
-    439			 * compliant with the old way of self restarting
-    440			 * itimers, as the SIGALRM is a legacy signal and only
-    441			 * queued once. Changing the restart behaviour to
-    442			 * restart the timer in the signal dequeue path is
-    443			 * reducing the timer noise on heavy loaded !highres
-    444			 * systems too.
-    445			 */
-    446			if (unlikely(signr == SIGALRM)) {
-    ...
-    489 }
-
-So instead of looking at 446, we should be looking at 431, which is the line
-that executes just before 446. Here we see that what we are looking for is
-``&tsk->signal->shared_pending``.
-
-Our next task is now to figure out which function that puts items on this
-``shared_pending`` list. A crude, but efficient tool, is ``git grep``::
-
-	$ git grep -n 'shared_pending' kernel/
-	...
-	kernel/signal.c:828:	pending = group ? &t->signal->shared_pending : &t->pending;
-	kernel/signal.c:1339:	pending = group ? &t->signal->shared_pending : &t->pending;
-	...
-
-There were more results, but none of them were related to list operations,
-and these were the only assignments. We inspect the line numbers more closely
-and find that this is indeed where items are being added to the list::
-
-    816 static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
-    817				int group)
-    818 {
-    ...
-    828		pending = group ? &t->signal->shared_pending : &t->pending;
-    ...
-    851		q = __sigqueue_alloc(t, GFP_ATOMIC, (sig < SIGRTMIN &&
-    852						     (is_si_special(info) ||
-    853						      info->si_code >= 0)));
-    854		if (q) {
-    855			list_add_tail(&q->list, &pending->list);
-    ...
-    890 }
-
-and::
-
-    1309 int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group)
-    1310 {
-    ....
-    1339	 pending = group ? &t->signal->shared_pending : &t->pending;
-    1340	 list_add_tail(&q->list, &pending->list);
-    ....
-    1347 }
-
-In the first case, the list element we are looking for, ``q``, is being
-returned from the function ``__sigqueue_alloc()``, which looks like an
-allocation function.  Let's take a look at it::
-
-    187 static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags,
-    188						 int override_rlimit)
-    189 {
-    190		struct sigqueue *q = NULL;
-    191		struct user_struct *user;
-    192
-    193		/*
-    194		 * We won't get problems with the target's UID changing under us
-    195		 * because changing it requires RCU be used, and if t != current, the
-    196		 * caller must be holding the RCU readlock (by way of a spinlock) and
-    197		 * we use RCU protection here
-    198		 */
-    199		user = get_uid(__task_cred(t)->user);
-    200		atomic_inc(&user->sigpending);
-    201		if (override_rlimit ||
-    202		    atomic_read(&user->sigpending) <=
-    203				t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur)
-    204			q = kmem_cache_alloc(sigqueue_cachep, flags);
-    205		if (unlikely(q == NULL)) {
-    206			atomic_dec(&user->sigpending);
-    207			free_uid(user);
-    208		} else {
-    209			INIT_LIST_HEAD(&q->list);
-    210			q->flags = 0;
-    211			q->user = user;
-    212		}
-    213
-    214		return q;
-    215 }
-
-We see that this function initializes ``q->list``, ``q->flags``, and
-``q->user``. It seems that now is the time to look at the definition of
-``struct sigqueue``, e.g.::
-
-    14 struct sigqueue {
-    15	       struct list_head list;
-    16	       int flags;
-    17	       siginfo_t info;
-    18	       struct user_struct *user;
-    19 };
-
-And, you might remember, it was a ``memcpy()`` on ``&first->info`` that
-caused the warning, so this makes perfect sense. It also seems reasonable
-to assume that it is the caller of ``__sigqueue_alloc()`` that has the
-responsibility of filling out (initializing) this member.
-
-But just which fields of the struct were uninitialized? Let's look at
-kmemcheck's report again::
-
-    WARNING: kmemcheck: Caught 32-bit read from uninitialized memory (ffff88003e4a2024)
-    80000000000000000000000000000000000000000088ffff0000000000000000
-     i i i i u u u u i i i i i i i i u u u u u u u u u u u u u u u u
-	     ^
-
-These first two lines are the memory dump of the memory object itself, and
-the shadow bytemap, respectively. The memory object itself is in this case
-``&first->info``. Just beware that the start of this dump is NOT the start
-of the object itself! The position of the caret (^) corresponds with the
-address of the read (ffff88003e4a2024).
-
-The shadow bytemap dump legend is as follows:
-
-- i: initialized
-- u: uninitialized
-- a: unallocated (memory has been allocated by the slab layer, but has not
-  yet been handed off to anybody)
-- f: freed (memory has been allocated by the slab layer, but has been freed
-  by the previous owner)
-
-In order to figure out where (relative to the start of the object) the
-uninitialized memory was located, we have to look at the disassembly. For
-that, we'll need the RIP address again::
-
-    RIP: 0010:[<ffffffff8104ede8>]  [<ffffffff8104ede8>] __dequeue_signal+0xc8/0x190
-
-	$ objdump -d --no-show-raw-insn vmlinux | grep -C 8 ffffffff8104ede8:
-	ffffffff8104edc8:	mov    %r8,0x8(%r8)
-	ffffffff8104edcc:	test   %r10d,%r10d
-	ffffffff8104edcf:	js     ffffffff8104ee88 <__dequeue_signal+0x168>
-	ffffffff8104edd5:	mov    %rax,%rdx
-	ffffffff8104edd8:	mov    $0xc,%ecx
-	ffffffff8104eddd:	mov    %r13,%rdi
-	ffffffff8104ede0:	mov    $0x30,%eax
-	ffffffff8104ede5:	mov    %rdx,%rsi
-	ffffffff8104ede8:	rep movsl %ds:(%rsi),%es:(%rdi)
-	ffffffff8104edea:	test   $0x2,%al
-	ffffffff8104edec:	je     ffffffff8104edf0 <__dequeue_signal+0xd0>
-	ffffffff8104edee:	movsw  %ds:(%rsi),%es:(%rdi)
-	ffffffff8104edf0:	test   $0x1,%al
-	ffffffff8104edf2:	je     ffffffff8104edf5 <__dequeue_signal+0xd5>
-	ffffffff8104edf4:	movsb  %ds:(%rsi),%es:(%rdi)
-	ffffffff8104edf5:	mov    %r8,%rdi
-	ffffffff8104edf8:	callq  ffffffff8104de60 <__sigqueue_free>
-
-As expected, it's the "``rep movsl``" instruction from the ``memcpy()``
-that causes the warning. We know about ``REP MOVSL`` that it uses the register
-``RCX`` to count the number of remaining iterations. By taking a look at the
-register dump again (from the kmemcheck report), we can figure out how many
-bytes were left to copy::
-
-    RAX: 0000000000000030 RBX: ffff88003d4ea968 RCX: 0000000000000009
-
-By looking at the disassembly, we also see that ``%ecx`` is being loaded
-with the value ``$0xc`` just before (ffffffff8104edd8), so we are very
-lucky. Keep in mind that this is the number of iterations, not bytes. And
-since this is a "long" operation, we need to multiply by 4 to get the
-number of bytes. So this means that the uninitialized value was encountered
-at 4 * (0xc - 0x9) = 12 bytes from the start of the object.
-
-We can now try to figure out which field of the "``struct siginfo``" that
-was not initialized. This is the beginning of the struct::
-
-    40 typedef struct siginfo {
-    41	       int si_signo;
-    42	       int si_errno;
-    43	       int si_code;
-    44
-    45	       union {
-    ..
-    92	       } _sifields;
-    93 } siginfo_t;
-
-On 64-bit, the int is 4 bytes long, so it must the union member that has
-not been initialized. We can verify this using gdb::
-
-	$ gdb vmlinux
-	...
-	(gdb) p &((struct siginfo *) 0)->_sifields
-	$1 = (union {...} *) 0x10
-
-Actually, it seems that the union member is located at offset 0x10 -- which
-means that gcc has inserted 4 bytes of padding between the members ``si_code``
-and ``_sifields``. We can now get a fuller picture of the memory dump::
-
-		 _----------------------------=> si_code
-		/	 _--------------------=> (padding)
-	       |	/	 _------------=> _sifields(._kill._pid)
-	       |       |	/	 _----=> _sifields(._kill._uid)
-	       |       |       |	/
-	-------|-------|-------|-------|
-	80000000000000000000000000000000000000000088ffff0000000000000000
-	 i i i i u u u u i i i i i i i i u u u u u u u u u u u u u u u u
-
-This allows us to realize another important fact: ``si_code`` contains the
-value 0x80. Remember that x86 is little endian, so the first 4 bytes
-"80000000" are really the number 0x00000080. With a bit of research, we
-find that this is actually the constant ``SI_KERNEL`` defined in
-``include/asm-generic/siginfo.h``::
-
-    144 #define SI_KERNEL	0x80		/* sent by the kernel from somewhere	 */
-
-This macro is used in exactly one place in the x86 kernel: In ``send_signal()``
-in ``kernel/signal.c``::
-
-    816 static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
-    817				int group)
-    818 {
-    ...
-    828		pending = group ? &t->signal->shared_pending : &t->pending;
-    ...
-    851		q = __sigqueue_alloc(t, GFP_ATOMIC, (sig < SIGRTMIN &&
-    852						     (is_si_special(info) ||
-    853						      info->si_code >= 0)));
-    854		if (q) {
-    855			list_add_tail(&q->list, &pending->list);
-    856			switch ((unsigned long) info) {
-    ...
-    865			case (unsigned long) SEND_SIG_PRIV:
-    866				q->info.si_signo = sig;
-    867				q->info.si_errno = 0;
-    868				q->info.si_code = SI_KERNEL;
-    869				q->info.si_pid = 0;
-    870				q->info.si_uid = 0;
-    871				break;
-    ...
-    890 }
-
-Not only does this match with the ``.si_code`` member, it also matches the place
-we found earlier when looking for where siginfo_t objects are enqueued on the
-``shared_pending`` list.
-
-So to sum up: It seems that it is the padding introduced by the compiler
-between two struct fields that is uninitialized, and this gets reported when
-we do a ``memcpy()`` on the struct. This means that we have identified a false
-positive warning.
-
-Normally, kmemcheck will not report uninitialized accesses in ``memcpy()`` calls
-when both the source and destination addresses are tracked. (Instead, we copy
-the shadow bytemap as well). In this case, the destination address clearly
-was not tracked. We can dig a little deeper into the stack trace from above::
-
-	arch/x86/kernel/signal.c:805
-	arch/x86/kernel/signal.c:871
-	arch/x86/kernel/entry_64.S:694
-
-And we clearly see that the destination siginfo object is located on the
-stack::
-
-    782 static void do_signal(struct pt_regs *regs)
-    783 {
-    784		struct k_sigaction ka;
-    785		siginfo_t info;
-    ...
-    804		signr = get_signal_to_deliver(&info, &ka, regs, NULL);
-    ...
-    854 }
-
-And this ``&info`` is what eventually gets passed to ``copy_siginfo()`` as the
-destination argument.
-
-Now, even though we didn't find an actual error here, the example is still a
-good one, because it shows how one would go about to find out what the report
-was all about.
-
-
-Annotating false positives
-~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-There are a few different ways to make annotations in the source code that
-will keep kmemcheck from checking and reporting certain allocations. Here
-they are:
-
-- ``__GFP_NOTRACK_FALSE_POSITIVE``
-	This flag can be passed to ``kmalloc()`` or ``kmem_cache_alloc()``
-	(therefore also to other functions that end up calling one of
-	these) to indicate that the allocation should not be tracked
-	because it would lead to a false positive report. This is a "big
-	hammer" way of silencing kmemcheck; after all, even if the false
-	positive pertains to particular field in a struct, for example, we
-	will now lose the ability to find (real) errors in other parts of
-	the same struct.
-
-	Example::
-
-	    /* No warnings will ever trigger on accessing any part of x */
-	    x = kmalloc(sizeof *x, GFP_KERNEL | __GFP_NOTRACK_FALSE_POSITIVE);
-
-- ``kmemcheck_bitfield_begin(name)``/``kmemcheck_bitfield_end(name)`` and
-	``kmemcheck_annotate_bitfield(ptr, name)``
-	The first two of these three macros can be used inside struct
-	definitions to signal, respectively, the beginning and end of a
-	bitfield. Additionally, this will assign the bitfield a name, which
-	is given as an argument to the macros.
-
-	Having used these markers, one can later use
-	kmemcheck_annotate_bitfield() at the point of allocation, to indicate
-	which parts of the allocation is part of a bitfield.
-
-	Example::
-
-	    struct foo {
-		int x;
-
-		kmemcheck_bitfield_begin(flags);
-		int flag_a:1;
-		int flag_b:1;
-		kmemcheck_bitfield_end(flags);
-
-		int y;
-	    };
-
-	    struct foo *x = kmalloc(sizeof *x);
-
-	    /* No warnings will trigger on accessing the bitfield of x */
-	    kmemcheck_annotate_bitfield(x, flags);
-
-	Note that ``kmemcheck_annotate_bitfield()`` can be used even before the
-	return value of ``kmalloc()`` is checked -- in other words, passing NULL
-	as the first argument is legal (and will do nothing).
-
-
-Reporting errors
-----------------
-
-As we have seen, kmemcheck will produce false positive reports. Therefore, it
-is not very wise to blindly post kmemcheck warnings to mailing lists and
-maintainers. Instead, I encourage maintainers and developers to find errors
-in their own code. If you get a warning, you can try to work around it, try
-to figure out if it's a real error or not, or simply ignore it. Most
-developers know their own code and will quickly and efficiently determine the
-root cause of a kmemcheck report. This is therefore also the most efficient
-way to work with kmemcheck.
-
-That said, we (the kmemcheck maintainers) will always be on the lookout for
-false positives that we can annotate and silence. So whatever you find,
-please drop us a note privately! Kernel configs and steps to reproduce (if
-available) are of course a great help too.
-
-Happy hacking!
-
-
-Technical description
----------------------
-
-kmemcheck works by marking memory pages non-present. This means that whenever
-somebody attempts to access the page, a page fault is generated. The page
-fault handler notices that the page was in fact only hidden, and so it calls
-on the kmemcheck code to make further investigations.
-
-When the investigations are completed, kmemcheck "shows" the page by marking
-it present (as it would be under normal circumstances). This way, the
-interrupted code can continue as usual.
-
-But after the instruction has been executed, we should hide the page again, so
-that we can catch the next access too! Now kmemcheck makes use of a debugging
-feature of the processor, namely single-stepping. When the processor has
-finished the one instruction that generated the memory access, a debug
-exception is raised. From here, we simply hide the page again and continue
-execution, this time with the single-stepping feature turned off.
-
-kmemcheck requires some assistance from the memory allocator in order to work.
-The memory allocator needs to
-
-  1. Tell kmemcheck about newly allocated pages and pages that are about to
-     be freed. This allows kmemcheck to set up and tear down the shadow memory
-     for the pages in question. The shadow memory stores the status of each
-     byte in the allocation proper, e.g. whether it is initialized or
-     uninitialized.
-
-  2. Tell kmemcheck which parts of memory should be marked uninitialized.
-     There are actually a few more states, such as "not yet allocated" and
-     "recently freed".
-
-If a slab cache is set up using the SLAB_NOTRACK flag, it will never return
-memory that can take page faults because of kmemcheck.
-
-If a slab cache is NOT set up using the SLAB_NOTRACK flag, callers can still
-request memory with the __GFP_NOTRACK or __GFP_NOTRACK_FALSE_POSITIVE flags.
-This does not prevent the page faults from occurring, however, but marks the
-object in question as being initialized so that no warnings will ever be
-produced for this object.
-
-Currently, the SLAB and SLUB allocators are supported by kmemcheck.
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7670,16 +7670,6 @@ F:	include/linux/kdb.h
 F:	include/linux/kgdb.h
 F:	kernel/debug/
 
-KMEMCHECK
-M:	Vegard Nossum <vegardno@xxxxxxxxxx>
-M:	Pekka Enberg <penberg@xxxxxxxxxx>
-S:	Maintained
-F:	Documentation/dev-tools/kmemcheck.rst
-F:	arch/x86/include/asm/kmemcheck.h
-F:	arch/x86/mm/kmemcheck/
-F:	include/linux/kmemcheck.h
-F:	mm/kmemcheck.c
-
 KMEMLEAK
 M:	Catalin Marinas <catalin.marinas@xxxxxxx>
 S:	Maintained
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -111,7 +111,6 @@ config X86
 	select HAVE_ARCH_JUMP_LABEL
 	select HAVE_ARCH_KASAN			if X86_64
 	select HAVE_ARCH_KGDB
-	select HAVE_ARCH_KMEMCHECK
 	select HAVE_ARCH_MMAP_RND_BITS		if MMU
 	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
 	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
@@ -1443,7 +1442,7 @@ config ARCH_DMA_ADDR_T_64BIT
 
 config X86_DIRECT_GBPAGES
 	def_bool y
-	depends on X86_64 && !DEBUG_PAGEALLOC && !KMEMCHECK
+	depends on X86_64 && !DEBUG_PAGEALLOC
 	---help---
 	  Certain kernel features effectively disable kernel
 	  linear 1 GB mappings (even if the CPU otherwise
--- a/arch/x86/include/asm/kmemcheck.h
+++ b/arch/x86/include/asm/kmemcheck.h
@@ -1,43 +1 @@
 /* SPDX-License-Identifier: GPL-2.0 */
-#ifndef ASM_X86_KMEMCHECK_H
-#define ASM_X86_KMEMCHECK_H
-
-#include <linux/types.h>
-#include <asm/ptrace.h>
-
-#ifdef CONFIG_KMEMCHECK
-bool kmemcheck_active(struct pt_regs *regs);
-
-void kmemcheck_show(struct pt_regs *regs);
-void kmemcheck_hide(struct pt_regs *regs);
-
-bool kmemcheck_fault(struct pt_regs *regs,
-	unsigned long address, unsigned long error_code);
-bool kmemcheck_trap(struct pt_regs *regs);
-#else
-static inline bool kmemcheck_active(struct pt_regs *regs)
-{
-	return false;
-}
-
-static inline void kmemcheck_show(struct pt_regs *regs)
-{
-}
-
-static inline void kmemcheck_hide(struct pt_regs *regs)
-{
-}
-
-static inline bool kmemcheck_fault(struct pt_regs *regs,
-	unsigned long address, unsigned long error_code)
-{
-	return false;
-}
-
-static inline bool kmemcheck_trap(struct pt_regs *regs)
-{
-	return false;
-}
-#endif /* CONFIG_KMEMCHECK */
-
-#endif
--- a/arch/x86/include/asm/string_32.h
+++ b/arch/x86/include/asm/string_32.h
@@ -179,8 +179,6 @@ static inline void *__memcpy3d(void *to,
  *	No 3D Now!
  */
 
-#ifndef CONFIG_KMEMCHECK
-
 #if (__GNUC__ >= 4)
 #define memcpy(t, f, n) __builtin_memcpy(t, f, n)
 #else
@@ -189,13 +187,6 @@ static inline void *__memcpy3d(void *to,
 	 ? __constant_memcpy((t), (f), (n))	\
 	 : __memcpy((t), (f), (n)))
 #endif
-#else
-/*
- * kmemcheck becomes very happy if we use the REP instructions unconditionally,
- * because it means that we know both memory operands in advance.
- */
-#define memcpy(t, f, n) __memcpy((t), (f), (n))
-#endif
 
 #endif
 #endif /* !CONFIG_FORTIFY_SOURCE */
--- a/arch/x86/include/asm/string_64.h
+++ b/arch/x86/include/asm/string_64.h
@@ -33,7 +33,6 @@ extern void *memcpy(void *to, const void
 extern void *__memcpy(void *to, const void *from, size_t len);
 
 #ifndef CONFIG_FORTIFY_SOURCE
-#ifndef CONFIG_KMEMCHECK
 #if (__GNUC__ == 4 && __GNUC_MINOR__ < 3) || __GNUC__ < 4
 #define memcpy(dst, src, len)					\
 ({								\
@@ -46,13 +45,6 @@ extern void *__memcpy(void *to, const vo
 	__ret;							\
 })
 #endif
-#else
-/*
- * kmemcheck becomes very happy if we use the REP instructions unconditionally,
- * because it means that we know both memory operands in advance.
- */
-#define memcpy(dst, src, len) __inline_memcpy((dst), (src), (len))
-#endif
 #endif /* !CONFIG_FORTIFY_SOURCE */
 
 #define __HAVE_ARCH_MEMSET
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -250,21 +250,6 @@ static void early_init_intel(struct cpui
 	if (c->x86 == 6 && c->x86_model < 15)
 		clear_cpu_cap(c, X86_FEATURE_PAT);
 
-#ifdef CONFIG_KMEMCHECK
-	/*
-	 * P4s have a "fast strings" feature which causes single-
-	 * stepping REP instructions to only generate a #DB on
-	 * cache-line boundaries.
-	 *
-	 * Ingo Molnar reported a Pentium D (model 6) and a Xeon
-	 * (model 2) with the same problem.
-	 */
-	if (c->x86 == 15)
-		if (msr_clear_bit(MSR_IA32_MISC_ENABLE,
-				  MSR_IA32_MISC_ENABLE_FAST_STRING_BIT) > 0)
-			pr_info("kmemcheck: Disabling fast string operations\n");
-#endif
-
 	/*
 	 * If fast string is not enabled in IA32_MISC_ENABLE for any reason,
 	 * clear the fast string and enhanced fast string CPU capabilities.
--- a/arch/x86/mm/Makefile
+++ b/arch/x86/mm/Makefile
@@ -29,8 +29,6 @@ obj-$(CONFIG_X86_PTDUMP)	+= debug_pageta
 
 obj-$(CONFIG_HIGHMEM)		+= highmem_32.o
 
-obj-$(CONFIG_KMEMCHECK)		+= kmemcheck/
-
 KASAN_SANITIZE_kasan_init_$(BITS).o := n
 obj-$(CONFIG_KASAN)		+= kasan_init_$(BITS).o
 
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -170,12 +170,11 @@ static void enable_global_pages(void)
 static void __init probe_page_size_mask(void)
 {
 	/*
-	 * For CONFIG_KMEMCHECK or pagealloc debugging, identity mapping will
-	 * use small pages.
+	 * For pagealloc debugging, identity mapping will use small pages.
 	 * This will simplify cpa(), which otherwise needs to support splitting
 	 * large pages into small in interrupt context, etc.
 	 */
-	if (boot_cpu_has(X86_FEATURE_PSE) && !debug_pagealloc_enabled() && !IS_ENABLED(CONFIG_KMEMCHECK))
+	if (boot_cpu_has(X86_FEATURE_PSE) && !debug_pagealloc_enabled())
 		page_size_mask |= 1 << PG_LEVEL_2M;
 	else
 		direct_gbpages = 0;
--- a/arch/x86/mm/kmemcheck/Makefile
+++ /dev/null
@@ -1 +0,0 @@
-obj-y := error.o kmemcheck.o opcode.o pte.o selftest.o shadow.o
--- a/arch/x86/mm/kmemcheck/error.c
+++ b/arch/x86/mm/kmemcheck/error.c
@@ -1,228 +1 @@
 // SPDX-License-Identifier: GPL-2.0
-#include <linux/interrupt.h>
-#include <linux/kdebug.h>
-#include <linux/kmemcheck.h>
-#include <linux/kernel.h>
-#include <linux/types.h>
-#include <linux/ptrace.h>
-#include <linux/stacktrace.h>
-#include <linux/string.h>
-
-#include "error.h"
-#include "shadow.h"
-
-enum kmemcheck_error_type {
-	KMEMCHECK_ERROR_INVALID_ACCESS,
-	KMEMCHECK_ERROR_BUG,
-};
-
-#define SHADOW_COPY_SIZE (1 << CONFIG_KMEMCHECK_SHADOW_COPY_SHIFT)
-
-struct kmemcheck_error {
-	enum kmemcheck_error_type type;
-
-	union {
-		/* KMEMCHECK_ERROR_INVALID_ACCESS */
-		struct {
-			/* Kind of access that caused the error */
-			enum kmemcheck_shadow state;
-			/* Address and size of the erroneous read */
-			unsigned long	address;
-			unsigned int	size;
-		};
-	};
-
-	struct pt_regs		regs;
-	struct stack_trace	trace;
-	unsigned long		trace_entries[32];
-
-	/* We compress it to a char. */
-	unsigned char		shadow_copy[SHADOW_COPY_SIZE];
-	unsigned char		memory_copy[SHADOW_COPY_SIZE];
-};
-
-/*
- * Create a ring queue of errors to output. We can't call printk() directly
- * from the kmemcheck traps, since this may call the console drivers and
- * result in a recursive fault.
- */
-static struct kmemcheck_error error_fifo[CONFIG_KMEMCHECK_QUEUE_SIZE];
-static unsigned int error_count;
-static unsigned int error_rd;
-static unsigned int error_wr;
-static unsigned int error_missed_count;
-
-static struct kmemcheck_error *error_next_wr(void)
-{
-	struct kmemcheck_error *e;
-
-	if (error_count == ARRAY_SIZE(error_fifo)) {
-		++error_missed_count;
-		return NULL;
-	}
-
-	e = &error_fifo[error_wr];
-	if (++error_wr == ARRAY_SIZE(error_fifo))
-		error_wr = 0;
-	++error_count;
-	return e;
-}
-
-static struct kmemcheck_error *error_next_rd(void)
-{
-	struct kmemcheck_error *e;
-
-	if (error_count == 0)
-		return NULL;
-
-	e = &error_fifo[error_rd];
-	if (++error_rd == ARRAY_SIZE(error_fifo))
-		error_rd = 0;
-	--error_count;
-	return e;
-}
-
-void kmemcheck_error_recall(void)
-{
-	static const char *desc[] = {
-		[KMEMCHECK_SHADOW_UNALLOCATED]		= "unallocated",
-		[KMEMCHECK_SHADOW_UNINITIALIZED]	= "uninitialized",
-		[KMEMCHECK_SHADOW_INITIALIZED]		= "initialized",
-		[KMEMCHECK_SHADOW_FREED]		= "freed",
-	};
-
-	static const char short_desc[] = {
-		[KMEMCHECK_SHADOW_UNALLOCATED]		= 'a',
-		[KMEMCHECK_SHADOW_UNINITIALIZED]	= 'u',
-		[KMEMCHECK_SHADOW_INITIALIZED]		= 'i',
-		[KMEMCHECK_SHADOW_FREED]		= 'f',
-	};
-
-	struct kmemcheck_error *e;
-	unsigned int i;
-
-	e = error_next_rd();
-	if (!e)
-		return;
-
-	switch (e->type) {
-	case KMEMCHECK_ERROR_INVALID_ACCESS:
-		printk(KERN_WARNING "WARNING: kmemcheck: Caught %d-bit read from %s memory (%p)\n",
-			8 * e->size, e->state < ARRAY_SIZE(desc) ?
-				desc[e->state] : "(invalid shadow state)",
-			(void *) e->address);
-
-		printk(KERN_WARNING);
-		for (i = 0; i < SHADOW_COPY_SIZE; ++i)
-			printk(KERN_CONT "%02x", e->memory_copy[i]);
-		printk(KERN_CONT "\n");
-
-		printk(KERN_WARNING);
-		for (i = 0; i < SHADOW_COPY_SIZE; ++i) {
-			if (e->shadow_copy[i] < ARRAY_SIZE(short_desc))
-				printk(KERN_CONT " %c", short_desc[e->shadow_copy[i]]);
-			else
-				printk(KERN_CONT " ?");
-		}
-		printk(KERN_CONT "\n");
-		printk(KERN_WARNING "%*c\n", 2 + 2
-			* (int) (e->address & (SHADOW_COPY_SIZE - 1)), '^');
-		break;
-	case KMEMCHECK_ERROR_BUG:
-		printk(KERN_EMERG "ERROR: kmemcheck: Fatal error\n");
-		break;
-	}
-
-	__show_regs(&e->regs, 1);
-	print_stack_trace(&e->trace, 0);
-}
-
-static void do_wakeup(unsigned long data)
-{
-	while (error_count > 0)
-		kmemcheck_error_recall();
-
-	if (error_missed_count > 0) {
-		printk(KERN_WARNING "kmemcheck: Lost %d error reports because "
-			"the queue was too small\n", error_missed_count);
-		error_missed_count = 0;
-	}
-}
-
-static DECLARE_TASKLET(kmemcheck_tasklet, &do_wakeup, 0);
-
-/*
- * Save the context of an error report.
- */
-void kmemcheck_error_save(enum kmemcheck_shadow state,
-	unsigned long address, unsigned int size, struct pt_regs *regs)
-{
-	static unsigned long prev_ip;
-
-	struct kmemcheck_error *e;
-	void *shadow_copy;
-	void *memory_copy;
-
-	/* Don't report several adjacent errors from the same EIP. */
-	if (regs->ip == prev_ip)
-		return;
-	prev_ip = regs->ip;
-
-	e = error_next_wr();
-	if (!e)
-		return;
-
-	e->type = KMEMCHECK_ERROR_INVALID_ACCESS;
-
-	e->state = state;
-	e->address = address;
-	e->size = size;
-
-	/* Save regs */
-	memcpy(&e->regs, regs, sizeof(*regs));
-
-	/* Save stack trace */
-	e->trace.nr_entries = 0;
-	e->trace.entries = e->trace_entries;
-	e->trace.max_entries = ARRAY_SIZE(e->trace_entries);
-	e->trace.skip = 0;
-	save_stack_trace_regs(regs, &e->trace);
-
-	/* Round address down to nearest 16 bytes */
-	shadow_copy = kmemcheck_shadow_lookup(address
-		& ~(SHADOW_COPY_SIZE - 1));
-	BUG_ON(!shadow_copy);
-
-	memcpy(e->shadow_copy, shadow_copy, SHADOW_COPY_SIZE);
-
-	kmemcheck_show_addr(address);
-	memory_copy = (void *) (address & ~(SHADOW_COPY_SIZE - 1));
-	memcpy(e->memory_copy, memory_copy, SHADOW_COPY_SIZE);
-	kmemcheck_hide_addr(address);
-
-	tasklet_hi_schedule_first(&kmemcheck_tasklet);
-}
-
-/*
- * Save the context of a kmemcheck bug.
- */
-void kmemcheck_error_save_bug(struct pt_regs *regs)
-{
-	struct kmemcheck_error *e;
-
-	e = error_next_wr();
-	if (!e)
-		return;
-
-	e->type = KMEMCHECK_ERROR_BUG;
-
-	memcpy(&e->regs, regs, sizeof(*regs));
-
-	e->trace.nr_entries = 0;
-	e->trace.entries = e->trace_entries;
-	e->trace.max_entries = ARRAY_SIZE(e->trace_entries);
-	e->trace.skip = 1;
-	save_stack_trace(&e->trace);
-
-	tasklet_hi_schedule_first(&kmemcheck_tasklet);
-}
--- a/arch/x86/mm/kmemcheck/error.h
+++ b/arch/x86/mm/kmemcheck/error.h
@@ -1,16 +1 @@
 /* SPDX-License-Identifier: GPL-2.0 */
-#ifndef ARCH__X86__MM__KMEMCHECK__ERROR_H
-#define ARCH__X86__MM__KMEMCHECK__ERROR_H
-
-#include <linux/ptrace.h>
-
-#include "shadow.h"
-
-void kmemcheck_error_save(enum kmemcheck_shadow state,
-	unsigned long address, unsigned int size, struct pt_regs *regs);
-
-void kmemcheck_error_save_bug(struct pt_regs *regs);
-
-void kmemcheck_error_recall(void);
-
-#endif
--- a/arch/x86/mm/kmemcheck/kmemcheck.c
+++ /dev/null
@@ -1,658 +0,0 @@
-/**
- * kmemcheck - a heavyweight memory checker for the linux kernel
- * Copyright (C) 2007, 2008  Vegard Nossum <vegardno@xxxxxxxxxx>
- * (With a lot of help from Ingo Molnar and Pekka Enberg.)
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License (version 2) as
- * published by the Free Software Foundation.
- */
-
-#include <linux/init.h>
-#include <linux/interrupt.h>
-#include <linux/kallsyms.h>
-#include <linux/kernel.h>
-#include <linux/kmemcheck.h>
-#include <linux/mm.h>
-#include <linux/page-flags.h>
-#include <linux/percpu.h>
-#include <linux/ptrace.h>
-#include <linux/string.h>
-#include <linux/types.h>
-
-#include <asm/cacheflush.h>
-#include <asm/kmemcheck.h>
-#include <asm/pgtable.h>
-#include <asm/tlbflush.h>
-
-#include "error.h"
-#include "opcode.h"
-#include "pte.h"
-#include "selftest.h"
-#include "shadow.h"
-
-
-#ifdef CONFIG_KMEMCHECK_DISABLED_BY_DEFAULT
-#  define KMEMCHECK_ENABLED 0
-#endif
-
-#ifdef CONFIG_KMEMCHECK_ENABLED_BY_DEFAULT
-#  define KMEMCHECK_ENABLED 1
-#endif
-
-#ifdef CONFIG_KMEMCHECK_ONESHOT_BY_DEFAULT
-#  define KMEMCHECK_ENABLED 2
-#endif
-
-int kmemcheck_enabled = KMEMCHECK_ENABLED;
-
-int __init kmemcheck_init(void)
-{
-#ifdef CONFIG_SMP
-	/*
-	 * Limit SMP to use a single CPU. We rely on the fact that this code
-	 * runs before SMP is set up.
-	 */
-	if (setup_max_cpus > 1) {
-		printk(KERN_INFO
-			"kmemcheck: Limiting number of CPUs to 1.\n");
-		setup_max_cpus = 1;
-	}
-#endif
-
-	if (!kmemcheck_selftest()) {
-		printk(KERN_INFO "kmemcheck: self-tests failed; disabling\n");
-		kmemcheck_enabled = 0;
-		return -EINVAL;
-	}
-
-	printk(KERN_INFO "kmemcheck: Initialized\n");
-	return 0;
-}
-
-early_initcall(kmemcheck_init);
-
-/*
- * We need to parse the kmemcheck= option before any memory is allocated.
- */
-static int __init param_kmemcheck(char *str)
-{
-	int val;
-	int ret;
-
-	if (!str)
-		return -EINVAL;
-
-	ret = kstrtoint(str, 0, &val);
-	if (ret)
-		return ret;
-	kmemcheck_enabled = val;
-	return 0;
-}
-
-early_param("kmemcheck", param_kmemcheck);
-
-int kmemcheck_show_addr(unsigned long address)
-{
-	pte_t *pte;
-
-	pte = kmemcheck_pte_lookup(address);
-	if (!pte)
-		return 0;
-
-	set_pte(pte, __pte(pte_val(*pte) | _PAGE_PRESENT));
-	__flush_tlb_one(address);
-	return 1;
-}
-
-int kmemcheck_hide_addr(unsigned long address)
-{
-	pte_t *pte;
-
-	pte = kmemcheck_pte_lookup(address);
-	if (!pte)
-		return 0;
-
-	set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_PRESENT));
-	__flush_tlb_one(address);
-	return 1;
-}
-
-struct kmemcheck_context {
-	bool busy;
-	int balance;
-
-	/*
-	 * There can be at most two memory operands to an instruction, but
-	 * each address can cross a page boundary -- so we may need up to
-	 * four addresses that must be hidden/revealed for each fault.
-	 */
-	unsigned long addr[4];
-	unsigned long n_addrs;
-	unsigned long flags;
-
-	/* Data size of the instruction that caused a fault. */
-	unsigned int size;
-};
-
-static DEFINE_PER_CPU(struct kmemcheck_context, kmemcheck_context);
-
-bool kmemcheck_active(struct pt_regs *regs)
-{
-	struct kmemcheck_context *data = this_cpu_ptr(&kmemcheck_context);
-
-	return data->balance > 0;
-}
-
-/* Save an address that needs to be shown/hidden */
-static void kmemcheck_save_addr(unsigned long addr)
-{
-	struct kmemcheck_context *data = this_cpu_ptr(&kmemcheck_context);
-
-	BUG_ON(data->n_addrs >= ARRAY_SIZE(data->addr));
-	data->addr[data->n_addrs++] = addr;
-}
-
-static unsigned int kmemcheck_show_all(void)
-{
-	struct kmemcheck_context *data = this_cpu_ptr(&kmemcheck_context);
-	unsigned int i;
-	unsigned int n;
-
-	n = 0;
-	for (i = 0; i < data->n_addrs; ++i)
-		n += kmemcheck_show_addr(data->addr[i]);
-
-	return n;
-}
-
-static unsigned int kmemcheck_hide_all(void)
-{
-	struct kmemcheck_context *data = this_cpu_ptr(&kmemcheck_context);
-	unsigned int i;
-	unsigned int n;
-
-	n = 0;
-	for (i = 0; i < data->n_addrs; ++i)
-		n += kmemcheck_hide_addr(data->addr[i]);
-
-	return n;
-}
-
-/*
- * Called from the #PF handler.
- */
-void kmemcheck_show(struct pt_regs *regs)
-{
-	struct kmemcheck_context *data = this_cpu_ptr(&kmemcheck_context);
-
-	BUG_ON(!irqs_disabled());
-
-	if (unlikely(data->balance != 0)) {
-		kmemcheck_show_all();
-		kmemcheck_error_save_bug(regs);
-		data->balance = 0;
-		return;
-	}
-
-	/*
-	 * None of the addresses actually belonged to kmemcheck. Note that
-	 * this is not an error.
-	 */
-	if (kmemcheck_show_all() == 0)
-		return;
-
-	++data->balance;
-
-	/*
-	 * The IF needs to be cleared as well, so that the faulting
-	 * instruction can run "uninterrupted". Otherwise, we might take
-	 * an interrupt and start executing that before we've had a chance
-	 * to hide the page again.
-	 *
-	 * NOTE: In the rare case of multiple faults, we must not override
-	 * the original flags:
-	 */
-	if (!(regs->flags & X86_EFLAGS_TF))
-		data->flags = regs->flags;
-
-	regs->flags |= X86_EFLAGS_TF;
-	regs->flags &= ~X86_EFLAGS_IF;
-}
-
-/*
- * Called from the #DB handler.
- */
-void kmemcheck_hide(struct pt_regs *regs)
-{
-	struct kmemcheck_context *data = this_cpu_ptr(&kmemcheck_context);
-	int n;
-
-	BUG_ON(!irqs_disabled());
-
-	if (unlikely(data->balance != 1)) {
-		kmemcheck_show_all();
-		kmemcheck_error_save_bug(regs);
-		data->n_addrs = 0;
-		data->balance = 0;
-
-		if (!(data->flags & X86_EFLAGS_TF))
-			regs->flags &= ~X86_EFLAGS_TF;
-		if (data->flags & X86_EFLAGS_IF)
-			regs->flags |= X86_EFLAGS_IF;
-		return;
-	}
-
-	if (kmemcheck_enabled)
-		n = kmemcheck_hide_all();
-	else
-		n = kmemcheck_show_all();
-
-	if (n == 0)
-		return;
-
-	--data->balance;
-
-	data->n_addrs = 0;
-
-	if (!(data->flags & X86_EFLAGS_TF))
-		regs->flags &= ~X86_EFLAGS_TF;
-	if (data->flags & X86_EFLAGS_IF)
-		regs->flags |= X86_EFLAGS_IF;
-}
-
-void kmemcheck_show_pages(struct page *p, unsigned int n)
-{
-	unsigned int i;
-
-	for (i = 0; i < n; ++i) {
-		unsigned long address;
-		pte_t *pte;
-		unsigned int level;
-
-		address = (unsigned long) page_address(&p[i]);
-		pte = lookup_address(address, &level);
-		BUG_ON(!pte);
-		BUG_ON(level != PG_LEVEL_4K);
-
-		set_pte(pte, __pte(pte_val(*pte) | _PAGE_PRESENT));
-		set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_HIDDEN));
-		__flush_tlb_one(address);
-	}
-}
-
-bool kmemcheck_page_is_tracked(struct page *p)
-{
-	/* This will also check the "hidden" flag of the PTE. */
-	return kmemcheck_pte_lookup((unsigned long) page_address(p));
-}
-
-void kmemcheck_hide_pages(struct page *p, unsigned int n)
-{
-	unsigned int i;
-
-	for (i = 0; i < n; ++i) {
-		unsigned long address;
-		pte_t *pte;
-		unsigned int level;
-
-		address = (unsigned long) page_address(&p[i]);
-		pte = lookup_address(address, &level);
-		BUG_ON(!pte);
-		BUG_ON(level != PG_LEVEL_4K);
-
-		set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_PRESENT));
-		set_pte(pte, __pte(pte_val(*pte) | _PAGE_HIDDEN));
-		__flush_tlb_one(address);
-	}
-}
-
-/* Access may NOT cross page boundary */
-static void kmemcheck_read_strict(struct pt_regs *regs,
-	unsigned long addr, unsigned int size)
-{
-	void *shadow;
-	enum kmemcheck_shadow status;
-
-	shadow = kmemcheck_shadow_lookup(addr);
-	if (!shadow)
-		return;
-
-	kmemcheck_save_addr(addr);
-	status = kmemcheck_shadow_test(shadow, size);
-	if (status == KMEMCHECK_SHADOW_INITIALIZED)
-		return;
-
-	if (kmemcheck_enabled)
-		kmemcheck_error_save(status, addr, size, regs);
-
-	if (kmemcheck_enabled == 2)
-		kmemcheck_enabled = 0;
-
-	/* Don't warn about it again. */
-	kmemcheck_shadow_set(shadow, size);
-}
-
-bool kmemcheck_is_obj_initialized(unsigned long addr, size_t size)
-{
-	enum kmemcheck_shadow status;
-	void *shadow;
-
-	shadow = kmemcheck_shadow_lookup(addr);
-	if (!shadow)
-		return true;
-
-	status = kmemcheck_shadow_test_all(shadow, size);
-
-	return status == KMEMCHECK_SHADOW_INITIALIZED;
-}
-
-/* Access may cross page boundary */
-static void kmemcheck_read(struct pt_regs *regs,
-	unsigned long addr, unsigned int size)
-{
-	unsigned long page = addr & PAGE_MASK;
-	unsigned long next_addr = addr + size - 1;
-	unsigned long next_page = next_addr & PAGE_MASK;
-
-	if (likely(page == next_page)) {
-		kmemcheck_read_strict(regs, addr, size);
-		return;
-	}
-
-	/*
-	 * What we do is basically to split the access across the
-	 * two pages and handle each part separately. Yes, this means
-	 * that we may now see reads that are 3 + 5 bytes, for
-	 * example (and if both are uninitialized, there will be two
-	 * reports), but it makes the code a lot simpler.
-	 */
-	kmemcheck_read_strict(regs, addr, next_page - addr);
-	kmemcheck_read_strict(regs, next_page, next_addr - next_page);
-}
-
-static void kmemcheck_write_strict(struct pt_regs *regs,
-	unsigned long addr, unsigned int size)
-{
-	void *shadow;
-
-	shadow = kmemcheck_shadow_lookup(addr);
-	if (!shadow)
-		return;
-
-	kmemcheck_save_addr(addr);
-	kmemcheck_shadow_set(shadow, size);
-}
-
-static void kmemcheck_write(struct pt_regs *regs,
-	unsigned long addr, unsigned int size)
-{
-	unsigned long page = addr & PAGE_MASK;
-	unsigned long next_addr = addr + size - 1;
-	unsigned long next_page = next_addr & PAGE_MASK;
-
-	if (likely(page == next_page)) {
-		kmemcheck_write_strict(regs, addr, size);
-		return;
-	}
-
-	/* See comment in kmemcheck_read(). */
-	kmemcheck_write_strict(regs, addr, next_page - addr);
-	kmemcheck_write_strict(regs, next_page, next_addr - next_page);
-}
-
-/*
- * Copying is hard. We have two addresses, each of which may be split across
- * a page (and each page will have different shadow addresses).
- */
-static void kmemcheck_copy(struct pt_regs *regs,
-	unsigned long src_addr, unsigned long dst_addr, unsigned int size)
-{
-	uint8_t shadow[8];
-	enum kmemcheck_shadow status;
-
-	unsigned long page;
-	unsigned long next_addr;
-	unsigned long next_page;
-
-	uint8_t *x;
-	unsigned int i;
-	unsigned int n;
-
-	BUG_ON(size > sizeof(shadow));
-
-	page = src_addr & PAGE_MASK;
-	next_addr = src_addr + size - 1;
-	next_page = next_addr & PAGE_MASK;
-
-	if (likely(page == next_page)) {
-		/* Same page */
-		x = kmemcheck_shadow_lookup(src_addr);
-		if (x) {
-			kmemcheck_save_addr(src_addr);
-			for (i = 0; i < size; ++i)
-				shadow[i] = x[i];
-		} else {
-			for (i = 0; i < size; ++i)
-				shadow[i] = KMEMCHECK_SHADOW_INITIALIZED;
-		}
-	} else {
-		n = next_page - src_addr;
-		BUG_ON(n > sizeof(shadow));
-
-		/* First page */
-		x = kmemcheck_shadow_lookup(src_addr);
-		if (x) {
-			kmemcheck_save_addr(src_addr);
-			for (i = 0; i < n; ++i)
-				shadow[i] = x[i];
-		} else {
-			/* Not tracked */
-			for (i = 0; i < n; ++i)
-				shadow[i] = KMEMCHECK_SHADOW_INITIALIZED;
-		}
-
-		/* Second page */
-		x = kmemcheck_shadow_lookup(next_page);
-		if (x) {
-			kmemcheck_save_addr(next_page);
-			for (i = n; i < size; ++i)
-				shadow[i] = x[i - n];
-		} else {
-			/* Not tracked */
-			for (i = n; i < size; ++i)
-				shadow[i] = KMEMCHECK_SHADOW_INITIALIZED;
-		}
-	}
-
-	page = dst_addr & PAGE_MASK;
-	next_addr = dst_addr + size - 1;
-	next_page = next_addr & PAGE_MASK;
-
-	if (likely(page == next_page)) {
-		/* Same page */
-		x = kmemcheck_shadow_lookup(dst_addr);
-		if (x) {
-			kmemcheck_save_addr(dst_addr);
-			for (i = 0; i < size; ++i) {
-				x[i] = shadow[i];
-				shadow[i] = KMEMCHECK_SHADOW_INITIALIZED;
-			}
-		}
-	} else {
-		n = next_page - dst_addr;
-		BUG_ON(n > sizeof(shadow));
-
-		/* First page */
-		x = kmemcheck_shadow_lookup(dst_addr);
-		if (x) {
-			kmemcheck_save_addr(dst_addr);
-			for (i = 0; i < n; ++i) {
-				x[i] = shadow[i];
-				shadow[i] = KMEMCHECK_SHADOW_INITIALIZED;
-			}
-		}
-
-		/* Second page */
-		x = kmemcheck_shadow_lookup(next_page);
-		if (x) {
-			kmemcheck_save_addr(next_page);
-			for (i = n; i < size; ++i) {
-				x[i - n] = shadow[i];
-				shadow[i] = KMEMCHECK_SHADOW_INITIALIZED;
-			}
-		}
-	}
-
-	status = kmemcheck_shadow_test(shadow, size);
-	if (status == KMEMCHECK_SHADOW_INITIALIZED)
-		return;
-
-	if (kmemcheck_enabled)
-		kmemcheck_error_save(status, src_addr, size, regs);
-
-	if (kmemcheck_enabled == 2)
-		kmemcheck_enabled = 0;
-}
-
-enum kmemcheck_method {
-	KMEMCHECK_READ,
-	KMEMCHECK_WRITE,
-};
-
-static void kmemcheck_access(struct pt_regs *regs,
-	unsigned long fallback_address, enum kmemcheck_method fallback_method)
-{
-	const uint8_t *insn;
-	const uint8_t *insn_primary;
-	unsigned int size;
-
-	struct kmemcheck_context *data = this_cpu_ptr(&kmemcheck_context);
-
-	/* Recursive fault -- ouch. */
-	if (data->busy) {
-		kmemcheck_show_addr(fallback_address);
-		kmemcheck_error_save_bug(regs);
-		return;
-	}
-
-	data->busy = true;
-
-	insn = (const uint8_t *) regs->ip;
-	insn_primary = kmemcheck_opcode_get_primary(insn);
-
-	kmemcheck_opcode_decode(insn, &size);
-
-	switch (insn_primary[0]) {
-#ifdef CONFIG_KMEMCHECK_BITOPS_OK
-		/* AND, OR, XOR */
-		/*
-		 * Unfortunately, these instructions have to be excluded from
-		 * our regular checking since they access only some (and not
-		 * all) bits. This clears out "bogus" bitfield-access warnings.
-		 */
-	case 0x80:
-	case 0x81:
-	case 0x82:
-	case 0x83:
-		switch ((insn_primary[1] >> 3) & 7) {
-			/* OR */
-		case 1:
-			/* AND */
-		case 4:
-			/* XOR */
-		case 6:
-			kmemcheck_write(regs, fallback_address, size);
-			goto out;
-
-			/* ADD */
-		case 0:
-			/* ADC */
-		case 2:
-			/* SBB */
-		case 3:
-			/* SUB */
-		case 5:
-			/* CMP */
-		case 7:
-			break;
-		}
-		break;
-#endif
-
-		/* MOVS, MOVSB, MOVSW, MOVSD */
-	case 0xa4:
-	case 0xa5:
-		/*
-		 * These instructions are special because they take two
-		 * addresses, but we only get one page fault.
-		 */
-		kmemcheck_copy(regs, regs->si, regs->di, size);
-		goto out;
-
-		/* CMPS, CMPSB, CMPSW, CMPSD */
-	case 0xa6:
-	case 0xa7:
-		kmemcheck_read(regs, regs->si, size);
-		kmemcheck_read(regs, regs->di, size);
-		goto out;
-	}
-
-	/*
-	 * If the opcode isn't special in any way, we use the data from the
-	 * page fault handler to determine the address and type of memory
-	 * access.
-	 */
-	switch (fallback_method) {
-	case KMEMCHECK_READ:
-		kmemcheck_read(regs, fallback_address, size);
-		goto out;
-	case KMEMCHECK_WRITE:
-		kmemcheck_write(regs, fallback_address, size);
-		goto out;
-	}
-
-out:
-	data->busy = false;
-}
-
-bool kmemcheck_fault(struct pt_regs *regs, unsigned long address,
-	unsigned long error_code)
-{
-	pte_t *pte;
-
-	/*
-	 * XXX: Is it safe to assume that memory accesses from virtual 86
-	 * mode or non-kernel code segments will _never_ access kernel
-	 * memory (e.g. tracked pages)? For now, we need this to avoid
-	 * invoking kmemcheck for PnP BIOS calls.
-	 */
-	if (regs->flags & X86_VM_MASK)
-		return false;
-	if (regs->cs != __KERNEL_CS)
-		return false;
-
-	pte = kmemcheck_pte_lookup(address);
-	if (!pte)
-		return false;
-
-	WARN_ON_ONCE(in_nmi());
-
-	if (error_code & 2)
-		kmemcheck_access(regs, address, KMEMCHECK_WRITE);
-	else
-		kmemcheck_access(regs, address, KMEMCHECK_READ);
-
-	kmemcheck_show(regs);
-	return true;
-}
-
-bool kmemcheck_trap(struct pt_regs *regs)
-{
-	if (!kmemcheck_active(regs))
-		return false;
-
-	/* We're done. */
-	kmemcheck_hide(regs);
-	return true;
-}
--- a/arch/x86/mm/kmemcheck/opcode.c
+++ b/arch/x86/mm/kmemcheck/opcode.c
@@ -1,107 +1 @@
 // SPDX-License-Identifier: GPL-2.0
-#include <linux/types.h>
-
-#include "opcode.h"
-
-static bool opcode_is_prefix(uint8_t b)
-{
-	return
-		/* Group 1 */
-		b == 0xf0 || b == 0xf2 || b == 0xf3
-		/* Group 2 */
-		|| b == 0x2e || b == 0x36 || b == 0x3e || b == 0x26
-		|| b == 0x64 || b == 0x65
-		/* Group 3 */
-		|| b == 0x66
-		/* Group 4 */
-		|| b == 0x67;
-}
-
-#ifdef CONFIG_X86_64
-static bool opcode_is_rex_prefix(uint8_t b)
-{
-	return (b & 0xf0) == 0x40;
-}
-#else
-static bool opcode_is_rex_prefix(uint8_t b)
-{
-	return false;
-}
-#endif
-
-#define REX_W (1 << 3)
-
-/*
- * This is a VERY crude opcode decoder. We only need to find the size of the
- * load/store that caused our #PF and this should work for all the opcodes
- * that we care about. Moreover, the ones who invented this instruction set
- * should be shot.
- */
-void kmemcheck_opcode_decode(const uint8_t *op, unsigned int *size)
-{
-	/* Default operand size */
-	int operand_size_override = 4;
-
-	/* prefixes */
-	for (; opcode_is_prefix(*op); ++op) {
-		if (*op == 0x66)
-			operand_size_override = 2;
-	}
-
-	/* REX prefix */
-	if (opcode_is_rex_prefix(*op)) {
-		uint8_t rex = *op;
-
-		++op;
-		if (rex & REX_W) {
-			switch (*op) {
-			case 0x63:
-				*size = 4;
-				return;
-			case 0x0f:
-				++op;
-
-				switch (*op) {
-				case 0xb6:
-				case 0xbe:
-					*size = 1;
-					return;
-				case 0xb7:
-				case 0xbf:
-					*size = 2;
-					return;
-				}
-
-				break;
-			}
-
-			*size = 8;
-			return;
-		}
-	}
-
-	/* escape opcode */
-	if (*op == 0x0f) {
-		++op;
-
-		/*
-		 * This is move with zero-extend and sign-extend, respectively;
-		 * we don't have to think about 0xb6/0xbe, because this is
-		 * already handled in the conditional below.
-		 */
-		if (*op == 0xb7 || *op == 0xbf)
-			operand_size_override = 2;
-	}
-
-	*size = (*op & 1) ? operand_size_override : 1;
-}
-
-const uint8_t *kmemcheck_opcode_get_primary(const uint8_t *op)
-{
-	/* skip prefixes */
-	while (opcode_is_prefix(*op))
-		++op;
-	if (opcode_is_rex_prefix(*op))
-		++op;
-	return op;
-}
--- a/arch/x86/mm/kmemcheck/opcode.h
+++ b/arch/x86/mm/kmemcheck/opcode.h
@@ -1,10 +1 @@
 /* SPDX-License-Identifier: GPL-2.0 */
-#ifndef ARCH__X86__MM__KMEMCHECK__OPCODE_H
-#define ARCH__X86__MM__KMEMCHECK__OPCODE_H
-
-#include <linux/types.h>
-
-void kmemcheck_opcode_decode(const uint8_t *op, unsigned int *size);
-const uint8_t *kmemcheck_opcode_get_primary(const uint8_t *op);
-
-#endif
--- a/arch/x86/mm/kmemcheck/pte.c
+++ b/arch/x86/mm/kmemcheck/pte.c
@@ -1,23 +1 @@
 // SPDX-License-Identifier: GPL-2.0
-#include <linux/mm.h>
-
-#include <asm/pgtable.h>
-
-#include "pte.h"
-
-pte_t *kmemcheck_pte_lookup(unsigned long address)
-{
-	pte_t *pte;
-	unsigned int level;
-
-	pte = lookup_address(address, &level);
-	if (!pte)
-		return NULL;
-	if (level != PG_LEVEL_4K)
-		return NULL;
-	if (!pte_hidden(*pte))
-		return NULL;
-
-	return pte;
-}
-
--- a/arch/x86/mm/kmemcheck/pte.h
+++ b/arch/x86/mm/kmemcheck/pte.h
@@ -1,11 +1 @@
 /* SPDX-License-Identifier: GPL-2.0 */
-#ifndef ARCH__X86__MM__KMEMCHECK__PTE_H
-#define ARCH__X86__MM__KMEMCHECK__PTE_H
-
-#include <linux/mm.h>
-
-#include <asm/pgtable.h>
-
-pte_t *kmemcheck_pte_lookup(unsigned long address);
-
-#endif
--- a/arch/x86/mm/kmemcheck/selftest.c
+++ b/arch/x86/mm/kmemcheck/selftest.c
@@ -1,71 +1 @@
 // SPDX-License-Identifier: GPL-2.0
-#include <linux/bug.h>
-#include <linux/kernel.h>
-
-#include "opcode.h"
-#include "selftest.h"
-
-struct selftest_opcode {
-	unsigned int expected_size;
-	const uint8_t *insn;
-	const char *desc;
-};
-
-static const struct selftest_opcode selftest_opcodes[] = {
-	/* REP MOVS */
-	{1, "\xf3\xa4", 		"rep movsb <mem8>, <mem8>"},
-	{4, "\xf3\xa5",			"rep movsl <mem32>, <mem32>"},
-
-	/* MOVZX / MOVZXD */
-	{1, "\x66\x0f\xb6\x51\xf8",	"movzwq <mem8>, <reg16>"},
-	{1, "\x0f\xb6\x51\xf8",		"movzwq <mem8>, <reg32>"},
-
-	/* MOVSX / MOVSXD */
-	{1, "\x66\x0f\xbe\x51\xf8",	"movswq <mem8>, <reg16>"},
-	{1, "\x0f\xbe\x51\xf8",		"movswq <mem8>, <reg32>"},
-
-#ifdef CONFIG_X86_64
-	/* MOVZX / MOVZXD */
-	{1, "\x49\x0f\xb6\x51\xf8",	"movzbq <mem8>, <reg64>"},
-	{2, "\x49\x0f\xb7\x51\xf8",	"movzbq <mem16>, <reg64>"},
-
-	/* MOVSX / MOVSXD */
-	{1, "\x49\x0f\xbe\x51\xf8",	"movsbq <mem8>, <reg64>"},
-	{2, "\x49\x0f\xbf\x51\xf8",	"movsbq <mem16>, <reg64>"},
-	{4, "\x49\x63\x51\xf8",		"movslq <mem32>, <reg64>"},
-#endif
-};
-
-static bool selftest_opcode_one(const struct selftest_opcode *op)
-{
-	unsigned size;
-
-	kmemcheck_opcode_decode(op->insn, &size);
-
-	if (size == op->expected_size)
-		return true;
-
-	printk(KERN_WARNING "kmemcheck: opcode %s: expected size %d, got %d\n",
-		op->desc, op->expected_size, size);
-	return false;
-}
-
-static bool selftest_opcodes_all(void)
-{
-	bool pass = true;
-	unsigned int i;
-
-	for (i = 0; i < ARRAY_SIZE(selftest_opcodes); ++i)
-		pass = pass && selftest_opcode_one(&selftest_opcodes[i]);
-
-	return pass;
-}
-
-bool kmemcheck_selftest(void)
-{
-	bool pass = true;
-
-	pass = pass && selftest_opcodes_all();
-
-	return pass;
-}
--- a/arch/x86/mm/kmemcheck/selftest.h
+++ b/arch/x86/mm/kmemcheck/selftest.h
@@ -1,7 +1 @@
 /* SPDX-License-Identifier: GPL-2.0 */
-#ifndef ARCH_X86_MM_KMEMCHECK_SELFTEST_H
-#define ARCH_X86_MM_KMEMCHECK_SELFTEST_H
-
-bool kmemcheck_selftest(void);
-
-#endif
--- a/arch/x86/mm/kmemcheck/shadow.c
+++ /dev/null
@@ -1,173 +0,0 @@
-#include <linux/kmemcheck.h>
-#include <linux/export.h>
-#include <linux/mm.h>
-
-#include <asm/page.h>
-#include <asm/pgtable.h>
-
-#include "pte.h"
-#include "shadow.h"
-
-/*
- * Return the shadow address for the given address. Returns NULL if the
- * address is not tracked.
- *
- * We need to be extremely careful not to follow any invalid pointers,
- * because this function can be called for *any* possible address.
- */
-void *kmemcheck_shadow_lookup(unsigned long address)
-{
-	pte_t *pte;
-	struct page *page;
-
-	if (!virt_addr_valid(address))
-		return NULL;
-
-	pte = kmemcheck_pte_lookup(address);
-	if (!pte)
-		return NULL;
-
-	page = virt_to_page(address);
-	if (!page->shadow)
-		return NULL;
-	return page->shadow + (address & (PAGE_SIZE - 1));
-}
-
-static void mark_shadow(void *address, unsigned int n,
-	enum kmemcheck_shadow status)
-{
-	unsigned long addr = (unsigned long) address;
-	unsigned long last_addr = addr + n - 1;
-	unsigned long page = addr & PAGE_MASK;
-	unsigned long last_page = last_addr & PAGE_MASK;
-	unsigned int first_n;
-	void *shadow;
-
-	/* If the memory range crosses a page boundary, stop there. */
-	if (page == last_page)
-		first_n = n;
-	else
-		first_n = page + PAGE_SIZE - addr;
-
-	shadow = kmemcheck_shadow_lookup(addr);
-	if (shadow)
-		memset(shadow, status, first_n);
-
-	addr += first_n;
-	n -= first_n;
-
-	/* Do full-page memset()s. */
-	while (n >= PAGE_SIZE) {
-		shadow = kmemcheck_shadow_lookup(addr);
-		if (shadow)
-			memset(shadow, status, PAGE_SIZE);
-
-		addr += PAGE_SIZE;
-		n -= PAGE_SIZE;
-	}
-
-	/* Do the remaining page, if any. */
-	if (n > 0) {
-		shadow = kmemcheck_shadow_lookup(addr);
-		if (shadow)
-			memset(shadow, status, n);
-	}
-}
-
-void kmemcheck_mark_unallocated(void *address, unsigned int n)
-{
-	mark_shadow(address, n, KMEMCHECK_SHADOW_UNALLOCATED);
-}
-
-void kmemcheck_mark_uninitialized(void *address, unsigned int n)
-{
-	mark_shadow(address, n, KMEMCHECK_SHADOW_UNINITIALIZED);
-}
-
-/*
- * Fill the shadow memory of the given address such that the memory at that
- * address is marked as being initialized.
- */
-void kmemcheck_mark_initialized(void *address, unsigned int n)
-{
-	mark_shadow(address, n, KMEMCHECK_SHADOW_INITIALIZED);
-}
-EXPORT_SYMBOL_GPL(kmemcheck_mark_initialized);
-
-void kmemcheck_mark_freed(void *address, unsigned int n)
-{
-	mark_shadow(address, n, KMEMCHECK_SHADOW_FREED);
-}
-
-void kmemcheck_mark_unallocated_pages(struct page *p, unsigned int n)
-{
-	unsigned int i;
-
-	for (i = 0; i < n; ++i)
-		kmemcheck_mark_unallocated(page_address(&p[i]), PAGE_SIZE);
-}
-
-void kmemcheck_mark_uninitialized_pages(struct page *p, unsigned int n)
-{
-	unsigned int i;
-
-	for (i = 0; i < n; ++i)
-		kmemcheck_mark_uninitialized(page_address(&p[i]), PAGE_SIZE);
-}
-
-void kmemcheck_mark_initialized_pages(struct page *p, unsigned int n)
-{
-	unsigned int i;
-
-	for (i = 0; i < n; ++i)
-		kmemcheck_mark_initialized(page_address(&p[i]), PAGE_SIZE);
-}
-
-enum kmemcheck_shadow kmemcheck_shadow_test(void *shadow, unsigned int size)
-{
-#ifdef CONFIG_KMEMCHECK_PARTIAL_OK
-	uint8_t *x;
-	unsigned int i;
-
-	x = shadow;
-
-	/*
-	 * Make sure _some_ bytes are initialized. Gcc frequently generates
-	 * code to access neighboring bytes.
-	 */
-	for (i = 0; i < size; ++i) {
-		if (x[i] == KMEMCHECK_SHADOW_INITIALIZED)
-			return x[i];
-	}
-
-	return x[0];
-#else
-	return kmemcheck_shadow_test_all(shadow, size);
-#endif
-}
-
-enum kmemcheck_shadow kmemcheck_shadow_test_all(void *shadow, unsigned int size)
-{
-	uint8_t *x;
-	unsigned int i;
-
-	x = shadow;
-
-	/* All bytes must be initialized. */
-	for (i = 0; i < size; ++i) {
-		if (x[i] != KMEMCHECK_SHADOW_INITIALIZED)
-			return x[i];
-	}
-
-	return x[0];
-}
-
-void kmemcheck_shadow_set(void *shadow, unsigned int size)
-{
-	uint8_t *x;
-	unsigned int i;
-
-	x = shadow;
-	for (i = 0; i < size; ++i)
-		x[i] = KMEMCHECK_SHADOW_INITIALIZED;
-}
--- a/arch/x86/mm/kmemcheck/shadow.h
+++ b/arch/x86/mm/kmemcheck/shadow.h
@@ -1,19 +1 @@
 /* SPDX-License-Identifier: GPL-2.0 */
-#ifndef ARCH__X86__MM__KMEMCHECK__SHADOW_H
-#define ARCH__X86__MM__KMEMCHECK__SHADOW_H
-
-enum kmemcheck_shadow {
-	KMEMCHECK_SHADOW_UNALLOCATED,
-	KMEMCHECK_SHADOW_UNINITIALIZED,
-	KMEMCHECK_SHADOW_INITIALIZED,
-	KMEMCHECK_SHADOW_FREED,
-};
-
-void *kmemcheck_shadow_lookup(unsigned long address);
-
-enum kmemcheck_shadow kmemcheck_shadow_test(void *shadow, unsigned int size);
-enum kmemcheck_shadow kmemcheck_shadow_test_all(void *shadow,
-						unsigned int size);
-void kmemcheck_shadow_set(void *shadow, unsigned int size);
-
-#endif
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -594,21 +594,6 @@ static inline void tasklet_hi_schedule(s
 		__tasklet_hi_schedule(t);
 }
 
-extern void __tasklet_hi_schedule_first(struct tasklet_struct *t);
-
-/*
- * This version avoids touching any other tasklets. Needed for kmemcheck
- * in order not to take any page faults while enqueueing this tasklet;
- * consider VERY carefully whether you really need this or
- * tasklet_hi_schedule()...
- */
-static inline void tasklet_hi_schedule_first(struct tasklet_struct *t)
-{
-	if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
-		__tasklet_hi_schedule_first(t);
-}
-
-
 static inline void tasklet_disable_nosync(struct tasklet_struct *t)
 {
 	atomic_inc(&t->count);
--- a/include/linux/kmemcheck.h
+++ b/include/linux/kmemcheck.h
@@ -1,172 +1 @@
 /* SPDX-License-Identifier: GPL-2.0 */
-#ifndef LINUX_KMEMCHECK_H
-#define LINUX_KMEMCHECK_H
-
-#include <linux/mm_types.h>
-#include <linux/types.h>
-
-#ifdef CONFIG_KMEMCHECK
-extern int kmemcheck_enabled;
-
-/* The slab-related functions. */
-void kmemcheck_alloc_shadow(struct page *page, int order, gfp_t flags, int node);
-void kmemcheck_free_shadow(struct page *page, int order);
-void kmemcheck_slab_alloc(struct kmem_cache *s, gfp_t gfpflags, void *object,
-			  size_t size);
-void kmemcheck_slab_free(struct kmem_cache *s, void *object, size_t size);
-
-void kmemcheck_pagealloc_alloc(struct page *p, unsigned int order,
-			       gfp_t gfpflags);
-
-void kmemcheck_show_pages(struct page *p, unsigned int n);
-void kmemcheck_hide_pages(struct page *p, unsigned int n);
-
-bool kmemcheck_page_is_tracked(struct page *p);
-
-void kmemcheck_mark_unallocated(void *address, unsigned int n);
-void kmemcheck_mark_uninitialized(void *address, unsigned int n);
-void kmemcheck_mark_initialized(void *address, unsigned int n);
-void kmemcheck_mark_freed(void *address, unsigned int n);
-
-void kmemcheck_mark_unallocated_pages(struct page *p, unsigned int n);
-void kmemcheck_mark_uninitialized_pages(struct page *p, unsigned int n);
-void kmemcheck_mark_initialized_pages(struct page *p, unsigned int n);
-
-int kmemcheck_show_addr(unsigned long address);
-int kmemcheck_hide_addr(unsigned long address);
-
-bool kmemcheck_is_obj_initialized(unsigned long addr, size_t size);
-
-/*
- * Bitfield annotations
- *
- * How to use: If you have a struct using bitfields, for example
- *
- *     struct a {
- *             int x:8, y:8;
- *     };
- *
- * then this should be rewritten as
- *
- *     struct a {
- *             kmemcheck_bitfield_begin(flags);
- *             int x:8, y:8;
- *             kmemcheck_bitfield_end(flags);
- *     };
- *
- * Now the "flags_begin" and "flags_end" members may be used to refer to the
- * beginning and end, respectively, of the bitfield (and things like
- * &x.flags_begin is allowed). As soon as the struct is allocated, the bit-
- * fields should be annotated:
- *
- *     struct a *a = kmalloc(sizeof(struct a), GFP_KERNEL);
- *     kmemcheck_annotate_bitfield(a, flags);
- */
-#define kmemcheck_bitfield_begin(name)	\
-	int name##_begin[0];
-
-#define kmemcheck_bitfield_end(name)	\
-	int name##_end[0];
-
-#define kmemcheck_annotate_bitfield(ptr, name)				\
-	do {								\
-		int _n;							\
-									\
-		if (!ptr)						\
-			break;						\
-									\
-		_n = (long) &((ptr)->name##_end)			\
-			- (long) &((ptr)->name##_begin);		\
-		BUILD_BUG_ON(_n < 0);					\
-									\
-		kmemcheck_mark_initialized(&((ptr)->name##_begin), _n);	\
-	} while (0)
-
-#define kmemcheck_annotate_variable(var)				\
-	do {								\
-		kmemcheck_mark_initialized(&(var), sizeof(var));	\
-	} while (0)							\
-
-#else
-#define kmemcheck_enabled 0
-
-static inline void
-kmemcheck_alloc_shadow(struct page *page, int order, gfp_t flags, int node)
-{
-}
-
-static inline void
-kmemcheck_free_shadow(struct page *page, int order)
-{
-}
-
-static inline void
-kmemcheck_slab_alloc(struct kmem_cache *s, gfp_t gfpflags, void *object,
-		     size_t size)
-{
-}
-
-static inline void kmemcheck_slab_free(struct kmem_cache *s, void *object,
-				       size_t size)
-{
-}
-
-static inline void kmemcheck_pagealloc_alloc(struct page *p,
-	unsigned int order, gfp_t gfpflags)
-{
-}
-
-static inline bool kmemcheck_page_is_tracked(struct page *p)
-{
-	return false;
-}
-
-static inline void kmemcheck_mark_unallocated(void *address, unsigned int n)
-{
-}
-
-static inline void kmemcheck_mark_uninitialized(void *address, unsigned int n)
-{
-}
-
-static inline void kmemcheck_mark_initialized(void *address, unsigned int n)
-{
-}
-
-static inline void kmemcheck_mark_freed(void *address, unsigned int n)
-{
-}
-
-static inline void kmemcheck_mark_unallocated_pages(struct page *p,
-						    unsigned int n)
-{
-}
-
-static inline void kmemcheck_mark_uninitialized_pages(struct page *p,
-						      unsigned int n)
-{
-}
-
-static inline void kmemcheck_mark_initialized_pages(struct page *p,
-						    unsigned int n)
-{
-}
-
-static inline bool kmemcheck_is_obj_initialized(unsigned long addr, size_t size)
-{
-	return true;
-}
-
-#define kmemcheck_bitfield_begin(name)
-#define kmemcheck_bitfield_end(name)
-#define kmemcheck_annotate_bitfield(ptr, name)	\
-	do {					\
-	} while (0)
-
-#define kmemcheck_annotate_variable(var)	\
-	do {					\
-	} while (0)
-
-#endif /* CONFIG_KMEMCHECK */
-
-#endif /* LINUX_KMEMCHECK_H */
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -486,16 +486,6 @@ void __tasklet_hi_schedule(struct taskle
 }
 EXPORT_SYMBOL(__tasklet_hi_schedule);
 
-void __tasklet_hi_schedule_first(struct tasklet_struct *t)
-{
-	BUG_ON(!irqs_disabled());
-
-	t->next = __this_cpu_read(tasklet_hi_vec.head);
-	__this_cpu_write(tasklet_hi_vec.head, t);
-	__raise_softirq_irqoff(HI_SOFTIRQ);
-}
-EXPORT_SYMBOL(__tasklet_hi_schedule_first);
-
 static __latent_entropy void tasklet_action(struct softirq_action *a)
 {
 	struct tasklet_struct *list;
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -30,7 +30,6 @@
 #include <linux/proc_fs.h>
 #include <linux/security.h>
 #include <linux/ctype.h>
-#include <linux/kmemcheck.h>
 #include <linux/kmemleak.h>
 #include <linux/fs.h>
 #include <linux/init.h>
@@ -1174,15 +1173,6 @@ static struct ctl_table kern_table[] = {
 		.extra2		= &one_thousand,
 	},
 #endif
-#ifdef CONFIG_KMEMCHECK
-	{
-		.procname	= "kmemcheck",
-		.data		= &kmemcheck_enabled,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec,
-	},
-#endif
 	{
 		.procname	= "panic_on_warn",
 		.data		= &panic_on_warn,
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -504,7 +504,7 @@ config DEBUG_OBJECTS_ENABLE_DEFAULT
 
 config DEBUG_SLAB
 	bool "Debug slab memory allocations"
-	depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
+	depends on DEBUG_KERNEL && SLAB
 	help
 	  Say Y here to have the kernel do limited verification on memory
 	  allocation as well as poisoning memory on free to catch use of freed
@@ -516,7 +516,7 @@ config DEBUG_SLAB_LEAK
 
 config SLUB_DEBUG_ON
 	bool "SLUB debugging on by default"
-	depends on SLUB && SLUB_DEBUG && !KMEMCHECK
+	depends on SLUB && SLUB_DEBUG
 	default n
 	help
 	  Boot with debugging on by default. SLUB boots by default with
@@ -730,8 +730,6 @@ config DEBUG_STACKOVERFLOW
 
 	  If in doubt, say "N".
 
-source "lib/Kconfig.kmemcheck"
-
 source "lib/Kconfig.kasan"
 
 endmenu # "Memory Debugging"
--- a/lib/Kconfig.kmemcheck
+++ /dev/null
@@ -1,94 +0,0 @@
-config HAVE_ARCH_KMEMCHECK
-	bool
-
-if HAVE_ARCH_KMEMCHECK
-
-menuconfig KMEMCHECK
-	bool "kmemcheck: trap use of uninitialized memory"
-	depends on DEBUG_KERNEL
-	depends on !X86_USE_3DNOW
-	depends on SLUB || SLAB
-	depends on !CC_OPTIMIZE_FOR_SIZE
-	depends on !FUNCTION_TRACER
-	select FRAME_POINTER
-	select STACKTRACE
-	default n
-	help
-	  This option enables tracing of dynamically allocated kernel memory
-	  to see if memory is used before it has been given an initial value.
-	  Be aware that this requires half of your memory for bookkeeping and
-	  will insert extra code at *every* read and write to tracked memory
-	  thus slow down the kernel code (but user code is unaffected).
-
-	  The kernel may be started with kmemcheck=0 or kmemcheck=1 to disable
-	  or enable kmemcheck at boot-time. If the kernel is started with
-	  kmemcheck=0, the large memory and CPU overhead is not incurred.
-
-choice
-	prompt "kmemcheck: default mode at boot"
-	depends on KMEMCHECK
-	default KMEMCHECK_ONESHOT_BY_DEFAULT
-	help
-	  This option controls the default behaviour of kmemcheck when the
-	  kernel boots and no kmemcheck= parameter is given.
-
-config KMEMCHECK_DISABLED_BY_DEFAULT
-	bool "disabled"
-	depends on KMEMCHECK
-
-config KMEMCHECK_ENABLED_BY_DEFAULT
-	bool "enabled"
-	depends on KMEMCHECK
-
-config KMEMCHECK_ONESHOT_BY_DEFAULT
-	bool "one-shot"
-	depends on KMEMCHECK
-	help
-	  In one-shot mode, only the first error detected is reported before
-	  kmemcheck is disabled.
-
-endchoice
-
-config KMEMCHECK_QUEUE_SIZE
-	int "kmemcheck: error queue size"
-	depends on KMEMCHECK
-	default 64
-	help
-	  Select the maximum number of errors to store in the queue. Since
-	  errors can occur virtually anywhere and in any context, we need a
-	  temporary storage area which is guarantueed not to generate any
-	  other faults. The queue will be emptied as soon as a tasklet may
-	  be scheduled. If the queue is full, new error reports will be
-	  lost.
-
-config KMEMCHECK_SHADOW_COPY_SHIFT
-	int "kmemcheck: shadow copy size (5 => 32 bytes, 6 => 64 bytes)"
-	depends on KMEMCHECK
-	range 2 8
-	default 5
-	help
-	  Select the number of shadow bytes to save along with each entry of
-	  the queue. These bytes indicate what parts of an allocation are
-	  initialized, uninitialized, etc. and will be displayed when an
-	  error is detected to help the debugging of a particular problem.
-
-config KMEMCHECK_PARTIAL_OK
-	bool "kmemcheck: allow partially uninitialized memory"
-	depends on KMEMCHECK
-	default y
-	help
-	  This option works around certain GCC optimizations that produce
-	  32-bit reads from 16-bit variables where the upper 16 bits are
-	  thrown away afterwards. This may of course also hide some real
-	  bugs.
-
-config KMEMCHECK_BITOPS_OK
-	bool "kmemcheck: allow bit-field manipulation"
-	depends on KMEMCHECK
-	default n
-	help
-	  This option silences warnings that would be generated for bit-field
-	  accesses where not all the bits are initialized at the same time.
-	  This may also hide some real bugs.
-
-endif
--- a/mm/Kconfig.debug
+++ b/mm/Kconfig.debug
@@ -11,7 +11,6 @@ config DEBUG_PAGEALLOC
 	bool "Debug page memory allocations"
 	depends on DEBUG_KERNEL
 	depends on !HIBERNATION || ARCH_SUPPORTS_DEBUG_PAGEALLOC && !PPC && !SPARC
-	depends on !KMEMCHECK
 	select PAGE_EXTENSION
 	select PAGE_POISONING if !ARCH_SUPPORTS_DEBUG_PAGEALLOC
 	---help---
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -17,7 +17,6 @@ KCOV_INSTRUMENT_slub.o := n
 KCOV_INSTRUMENT_page_alloc.o := n
 KCOV_INSTRUMENT_debug-pagealloc.o := n
 KCOV_INSTRUMENT_kmemleak.o := n
-KCOV_INSTRUMENT_kmemcheck.o := n
 KCOV_INSTRUMENT_memcontrol.o := n
 KCOV_INSTRUMENT_mmzone.o := n
 KCOV_INSTRUMENT_vmstat.o := n
@@ -70,7 +69,6 @@ obj-$(CONFIG_KSM) += ksm.o
 obj-$(CONFIG_PAGE_POISONING) += page_poison.o
 obj-$(CONFIG_SLAB) += slab.o
 obj-$(CONFIG_SLUB) += slub.o
-obj-$(CONFIG_KMEMCHECK) += kmemcheck.o
 obj-$(CONFIG_KASAN)	+= kasan/
 obj-$(CONFIG_FAILSLAB) += failslab.o
 obj-$(CONFIG_MEMORY_HOTPLUG) += memory_hotplug.o
--- a/mm/kmemcheck.c
+++ b/mm/kmemcheck.c
@@ -1,126 +1 @@
 // SPDX-License-Identifier: GPL-2.0
-#include <linux/gfp.h>
-#include <linux/mm_types.h>
-#include <linux/mm.h>
-#include <linux/slab.h>
-#include "slab.h"
-#include <linux/kmemcheck.h>
-
-void kmemcheck_alloc_shadow(struct page *page, int order, gfp_t flags, int node)
-{
-	struct page *shadow;
-	int pages;
-	int i;
-
-	pages = 1 << order;
-
-	/*
-	 * With kmemcheck enabled, we need to allocate a memory area for the
-	 * shadow bits as well.
-	 */
-	shadow = alloc_pages_node(node, flags, order);
-	if (!shadow) {
-		if (printk_ratelimit())
-			pr_err("kmemcheck: failed to allocate shadow bitmap\n");
-		return;
-	}
-
-	for(i = 0; i < pages; ++i)
-		page[i].shadow = page_address(&shadow[i]);
-
-	/*
-	 * Mark it as non-present for the MMU so that our accesses to
-	 * this memory will trigger a page fault and let us analyze
-	 * the memory accesses.
-	 */
-	kmemcheck_hide_pages(page, pages);
-}
-
-void kmemcheck_free_shadow(struct page *page, int order)
-{
-	struct page *shadow;
-	int pages;
-	int i;
-
-	if (!kmemcheck_page_is_tracked(page))
-		return;
-
-	pages = 1 << order;
-
-	kmemcheck_show_pages(page, pages);
-
-	shadow = virt_to_page(page[0].shadow);
-
-	for(i = 0; i < pages; ++i)
-		page[i].shadow = NULL;
-
-	__free_pages(shadow, order);
-}
-
-void kmemcheck_slab_alloc(struct kmem_cache *s, gfp_t gfpflags, void *object,
-			  size_t size)
-{
-	if (unlikely(!object)) /* Skip object if allocation failed */
-		return;
-
-	/*
-	 * Has already been memset(), which initializes the shadow for us
-	 * as well.
-	 */
-	if (gfpflags & __GFP_ZERO)
-		return;
-
-	/* No need to initialize the shadow of a non-tracked slab. */
-	if (s->flags & SLAB_NOTRACK)
-		return;
-
-	if (!kmemcheck_enabled || gfpflags & __GFP_NOTRACK) {
-		/*
-		 * Allow notracked objects to be allocated from
-		 * tracked caches. Note however that these objects
-		 * will still get page faults on access, they just
-		 * won't ever be flagged as uninitialized. If page
-		 * faults are not acceptable, the slab cache itself
-		 * should be marked NOTRACK.
-		 */
-		kmemcheck_mark_initialized(object, size);
-	} else if (!s->ctor) {
-		/*
-		 * New objects should be marked uninitialized before
-		 * they're returned to the called.
-		 */
-		kmemcheck_mark_uninitialized(object, size);
-	}
-}
-
-void kmemcheck_slab_free(struct kmem_cache *s, void *object, size_t size)
-{
-	/* TODO: RCU freeing is unsupported for now; hide false positives. */
-	if (!s->ctor && !(s->flags & SLAB_TYPESAFE_BY_RCU))
-		kmemcheck_mark_freed(object, size);
-}
-
-void kmemcheck_pagealloc_alloc(struct page *page, unsigned int order,
-			       gfp_t gfpflags)
-{
-	int pages;
-
-	if (gfpflags & (__GFP_HIGHMEM | __GFP_NOTRACK))
-		return;
-
-	pages = 1 << order;
-
-	/*
-	 * NOTE: We choose to track GFP_ZERO pages too; in fact, they
-	 * can become uninitialized by copying uninitialized memory
-	 * into them.
-	 */
-
-	/* XXX: Can use zone->node for node? */
-	kmemcheck_alloc_shadow(page, order, gfpflags, -1);
-
-	if (gfpflags & __GFP_ZERO)
-		kmemcheck_mark_initialized_pages(page, pages);
-	else
-		kmemcheck_mark_uninitialized_pages(page, pages);
-}
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1369,7 +1369,7 @@ static inline void *slab_free_hook(struc
 	 * So in order to make the debug calls that expect irqs to be
 	 * disabled we need to disable interrupts temporarily.
 	 */
-#if defined(CONFIG_KMEMCHECK) || defined(CONFIG_LOCKDEP)
+#ifdef CONFIG_LOCKDEP
 	{
 		unsigned long flags;
 
@@ -1397,8 +1397,7 @@ static inline void slab_free_freelist_ho
  * Compiler cannot detect this function can be removed if slab_free_hook()
  * evaluates to nothing.  Thus, catch all relevant config debug options here.
  */
-#if defined(CONFIG_KMEMCHECK) ||		\
-	defined(CONFIG_LOCKDEP)	||		\
+#if defined(CONFIG_LOCKDEP)	||		\
 	defined(CONFIG_DEBUG_KMEMLEAK) ||	\
 	defined(CONFIG_DEBUG_OBJECTS_FREE) ||	\
 	defined(CONFIG_KASAN)
--- a/scripts/kernel-doc
+++ b/scripts/kernel-doc
@@ -2182,8 +2182,6 @@ sub dump_struct($$) {
 	# strip comments:
 	$members =~ s/\/\*.*?\*\///gos;
 	$nested =~ s/\/\*.*?\*\///gos;
-	# strip kmemcheck_bitfield_{begin,end}.*;
-	$members =~ s/kmemcheck_bitfield_.*?;//gos;
 	# strip attributes
 	$members =~ s/__attribute__\s*\(\([a-z,_\*\s\(\)]*\)\)//i;
 	$members =~ s/__aligned\s*\([^;]*\)//gos;
--- a/tools/include/linux/kmemcheck.h
+++ b/tools/include/linux/kmemcheck.h
@@ -1,9 +1 @@
 /* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _LIBLOCKDEP_LINUX_KMEMCHECK_H_
-#define _LIBLOCKDEP_LINUX_KMEMCHECK_H_
-
-static inline void kmemcheck_mark_initialized(void *address, unsigned int n)
-{
-}
-
-#endif