[GIT PULL] MM fixes

From: Ingo Molnar
Date: Sat Oct 22 2016 - 06:45:30 EST

Next message: Boris Brezillon: "Re: [PATCH v3 3/6] pwm: imx: support output polarity inversion"
Previous message: Greg KH: "Re: Linux 4.8.4"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

Linus,

Please pull the latest mm-urgent-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git mm-urgent-for-linus

# HEAD: d17af5056cf9e9fc05e68832f7c15687fcc12281 mm: Change vm_is_stack_for_task() to vm_is_stack_for_current()

This is fallout from CONFIG_HAVE_ARCH_VMAP_STACK=y on x86: stack accesses that
used to be just somewhat questionable are now totally buggy.

These changes try to do it without breaking the ABI: the fields are left there,
they are just reporting zero, or reporting narrower information (the maps file
change).

Thanks,

Ingo

------------------>
Andy Lutomirski (3):
fs/proc: Stop reporting eip and esp in /proc/PID/stat
fs/proc: Stop trying to report thread stacks
mm: Change vm_is_stack_for_task() to vm_is_stack_for_current()

Wei Yongjun (1):
mm/numa: Remove duplicated include from mprotect.c

Documentation/filesystems/proc.txt | 26 --------------------------
fs/proc/array.c | 9 +++++----
fs/proc/task_mmu.c | 29 ++++++++++-------------------
fs/proc/task_nommu.c | 28 ++++++++++------------------
include/linux/mm.h | 2 +-
mm/mprotect.c | 1 -
mm/util.c | 4 +++-
security/selinux/hooks.c | 2 +-
8 files changed, 30 insertions(+), 71 deletions(-)

diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index 219ffd41a911..74329fd0add2 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -395,32 +395,6 @@ The "pathname" shows the name associated file for this mapping. If the mapping

or if empty, the mapping is anonymous.

-The /proc/PID/task/TID/maps is a view of the virtual memory from the viewpoint
-of the individual tasks of a process. In this file you will see a mapping marked
-as [stack] if that task sees it as a stack. Hence, for the example above, the
-task-level map, i.e. /proc/PID/task/TID/maps for thread 1001 will look like this:
-
-08048000-08049000 r-xp 00000000 03:00 8312 /opt/test
-08049000-0804a000 rw-p 00001000 03:00 8312 /opt/test
-0804a000-0806b000 rw-p 00000000 00:00 0 [heap]
-a7cb1000-a7cb2000 ---p 00000000 00:00 0
-a7cb2000-a7eb2000 rw-p 00000000 00:00 0
-a7eb2000-a7eb3000 ---p 00000000 00:00 0
-a7eb3000-a7ed5000 rw-p 00000000 00:00 0 [stack]
-a7ed5000-a8008000 r-xp 00000000 03:00 4222 /lib/libc.so.6
-a8008000-a800a000 r--p 00133000 03:00 4222 /lib/libc.so.6
-a800a000-a800b000 rw-p 00135000 03:00 4222 /lib/libc.so.6
-a800b000-a800e000 rw-p 00000000 00:00 0
-a800e000-a8022000 r-xp 00000000 03:00 14462 /lib/libpthread.so.0
-a8022000-a8023000 r--p 00013000 03:00 14462 /lib/libpthread.so.0
-a8023000-a8024000 rw-p 00014000 03:00 14462 /lib/libpthread.so.0
-a8024000-a8027000 rw-p 00000000 00:00 0
-a8027000-a8043000 r-xp 00000000 03:00 8317 /lib/ld-linux.so.2
-a8043000-a8044000 r--p 0001b000 03:00 8317 /lib/ld-linux.so.2
-a8044000-a8045000 rw-p 0001c000 03:00 8317 /lib/ld-linux.so.2
-aff35000-aff4a000 rw-p 00000000 00:00 0
-ffffe000-fffff000 r-xp 00000000 00:00 0 [vdso]
-
The /proc/PID/smaps is an extension based on maps, showing the memory
consumption for each of the process's mappings. For each of mappings there
is a series of lines such as the following:
diff --git a/fs/proc/array.c b/fs/proc/array.c
index 89600fd5963d..81818adb8e9e 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -412,10 +412,11 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
mm = get_task_mm(task);
if (mm) {
vsize = task_vsize(mm);
- if (permitted) {
- eip = KSTK_EIP(task);
- esp = KSTK_ESP(task);
- }
+ /*
+ * esp and eip are intentionally zeroed out. There is no
+ * non-racy way to read them without freezing the task.
+ * Programs that need reliable values can use ptrace(2).
+ */
}

get_task_comm(tcomm, task);
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 6909582ce5e5..35b92d81692f 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -266,24 +266,15 @@ static int do_maps_open(struct inode *inode, struct file *file,
* /proc/PID/maps that is the stack of the main task.
*/
static int is_stack(struct proc_maps_private *priv,
- struct vm_area_struct *vma, int is_pid)
+ struct vm_area_struct *vma)
{
- int stack = 0;
-
- if (is_pid) {
- stack = vma->vm_start <= vma->vm_mm->start_stack &&
- vma->vm_end >= vma->vm_mm->start_stack;
- } else {
- struct inode *inode = priv->inode;
- struct task_struct *task;
-
- rcu_read_lock();
- task = pid_task(proc_pid(inode), PIDTYPE_PID);
- if (task)
- stack = vma_is_stack_for_task(vma, task);
- rcu_read_unlock();
- }
- return stack;
+ /*
+ * We make no effort to guess what a given thread considers to be
+ * its "stack". It's not even well-defined for programs written
+ * languages like Go.
+ */
+ return vma->vm_start <= vma->vm_mm->start_stack &&
+ vma->vm_end >= vma->vm_mm->start_stack;
}

static void
@@ -354,7 +345,7 @@ show_map_vma(struct seq_file *m, struct vm_area_struct *vma, int is_pid)
goto done;
}

- if (is_stack(priv, vma, is_pid))
+ if (is_stack(priv, vma))
name = "[stack]";
}

@@ -1669,7 +1660,7 @@ static int show_numa_map(struct seq_file *m, void *v, int is_pid)
seq_file_path(m, file, "\n\t= ");
} else if (vma->vm_start <= mm->brk && vma->vm_end >= mm->start_brk) {
seq_puts(m, " heap");
- } else if (is_stack(proc_priv, vma, is_pid)) {
+ } else if (is_stack(proc_priv, vma)) {
seq_puts(m, " stack");
}

diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c
index faacb0c0d857..37175621e890 100644
--- a/fs/proc/task_nommu.c
+++ b/fs/proc/task_nommu.c
@@ -124,25 +124,17 @@ unsigned long task_statm(struct mm_struct *mm,
}

static int is_stack(struct proc_maps_private *priv,
- struct vm_area_struct *vma, int is_pid)
+ struct vm_area_struct *vma)
{
struct mm_struct *mm = vma->vm_mm;
- int stack = 0;
-
- if (is_pid) {
- stack = vma->vm_start <= mm->start_stack &&
- vma->vm_end >= mm->start_stack;
- } else {
- struct inode *inode = priv->inode;
- struct task_struct *task;
-
- rcu_read_lock();
- task = pid_task(proc_pid(inode), PIDTYPE_PID);
- if (task)
- stack = vma_is_stack_for_task(vma, task);
- rcu_read_unlock();
- }
- return stack;
+
+ /*
+ * We make no effort to guess what a given thread considers to be
+ * its "stack". It's not even well-defined for programs written
+ * languages like Go.
+ */
+ return vma->vm_start <= mm->start_stack &&
+ vma->vm_end >= mm->start_stack;
}

/*
@@ -184,7 +176,7 @@ static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma,
if (file) {
seq_pad(m, ' ');
seq_file_path(m, file, "");
- } else if (mm && is_stack(priv, vma, is_pid)) {
+ } else if (mm && is_stack(priv, vma)) {
seq_pad(m, ' ');
seq_printf(m, "[stack]");
}
diff --git a/include/linux/mm.h b/include/linux/mm.h
index e9caec6a51e9..a658a5167bce 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1391,7 +1391,7 @@ static inline int stack_guard_page_end(struct vm_area_struct *vma,
!vma_growsup(vma->vm_next, addr);
}

-int vma_is_stack_for_task(struct vm_area_struct *vma, struct task_struct *t);
+int vma_is_stack_for_current(struct vm_area_struct *vma);

extern unsigned long move_page_tables(struct vm_area_struct *vma,
unsigned long old_addr, struct vm_area_struct *new_vma,
diff --git a/mm/mprotect.c b/mm/mprotect.c
index bcdbe62f3e6d..11936526b08b 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -25,7 +25,6 @@
#include <linux/perf_event.h>
#include <linux/pkeys.h>
#include <linux/ksm.h>
-#include <linux/pkeys.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/cacheflush.h>
diff --git a/mm/util.c b/mm/util.c
index 662cddf914af..c174e8921995 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -230,8 +230,10 @@ void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
}

/* Check if the vma is being used as a stack by this task */
-int vma_is_stack_for_task(struct vm_area_struct *vma, struct task_struct *t)
+int vma_is_stack_for_current(struct vm_area_struct *vma)
{
+ struct task_struct * __maybe_unused t = current;
+
return (vma->vm_start <= KSTK_ESP(t) && vma->vm_end >= KSTK_ESP(t));
}

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 085057936287..09fd6108e421 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3557,7 +3557,7 @@ static int selinux_file_mprotect(struct vm_area_struct *vma,
} else if (!vma->vm_file &&
((vma->vm_start <= vma->vm_mm->start_stack &&
vma->vm_end >= vma->vm_mm->start_stack) ||
- vma_is_stack_for_task(vma, current))) {
+ vma_is_stack_for_current(vma))) {
rc = current_has_perm(current, PROCESS__EXECSTACK);
} else if (vma->vm_file && vma->anon_vma) {
/*

Next message: Boris Brezillon: "Re: [PATCH v3 3/6] pwm: imx: support output polarity inversion"
Previous message: Greg KH: "Re: Linux 4.8.4"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]