[PATCH 5.18 161/181] mm/memory-failure: disable unpoison once hw error happens

From: Greg Kroah-Hartman
Date: Mon Jun 27 2022 - 08:01:43 EST

From: zhenwei pi <pizhenwei@xxxxxxxxxxxxx>

commit 67f22ba7750f940bcd7e1b12720896c505c2d63f upstream.

Currently unpoison_memory(unsigned long pfn) is designed for soft
poison(hwpoison-inject) only. Since 17fae1294ad9d, the KPTE gets cleared
on a x86 platform once hardware memory corrupts.

Unpoisoning a hardware corrupted page puts page back buddy only, the
kernel has a chance to access the page with *NOT PRESENT* KPTE. This
leads BUG during accessing on the corrupted KPTE.

Suggested by David&Naoya, disable unpoison mechanism when a real HW error
happens to avoid BUG like this:

Unpoison: Software-unpoisoned page 0x61234
BUG: unable to handle page fault for address: ffff888061234000
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 2c01067 P4D 2c01067 PUD 107267063 PMD 10382b063 PTE 800fffff9edcb062
Oops: 0002 [#1] PREEMPT SMP NOPTI
CPU: 4 PID: 26551 Comm: stress Kdump: loaded Tainted: G M OE 5.18.0.bm.1-amd64 #7
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) ...
RIP: 0010:clear_page_erms+0x7/0x10
Code: ...
RSP: 0000:ffffc90001107bc8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000901 RCX: 0000000000001000
RDX: ffffea0001848d00 RSI: ffffea0001848d40 RDI: ffff888061234000
RBP: ffffea0001848d00 R08: 0000000000000901 R09: 0000000000001276
R10: 0000000000000003 R11: 0000000000000000 R12: 0000000000000001
R13: 0000000000000000 R14: 0000000000140dca R15: 0000000000000001
FS: 00007fd8b2333740(0000) GS:ffff88813fd00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff888061234000 CR3: 00000001023d2005 CR4: 0000000000770ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
<TASK>
prep_new_page+0x151/0x170
get_page_from_freelist+0xca0/0xe20
? sysvec_apic_timer_interrupt+0xab/0xc0
? asm_sysvec_apic_timer_interrupt+0x1b/0x20
__alloc_pages+0x17e/0x340
__folio_alloc+0x17/0x40
vma_alloc_folio+0x84/0x280
__handle_mm_fault+0x8d4/0xeb0
handle_mm_fault+0xd5/0x2a0
do_user_addr_fault+0x1d0/0x680
? kvm_read_and_reset_apf_flags+0x3b/0x50
exc_page_fault+0x78/0x170
asm_exc_page_fault+0x27/0x30

Link: https://lkml.kernel.org/r/20220615093209.259374-2-pizhenwei@xxxxxxxxxxxxx
Fixes: 847ce401df392 ("HWPOISON: Add unpoisoning support")
Fixes: 17fae1294ad9d ("x86/{mce,mm}: Unmap the entire page if the whole page is affected and poisoned")
Signed-off-by: zhenwei pi <pizhenwei@xxxxxxxxxxxxx>
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
Acked-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Reviewed-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Reviewed-by: Oscar Salvador <osalvador@xxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> [5.8+]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
Documentation/vm/hwpoison.rst | 3 ++-
drivers/base/memory.c | 2 +-
include/linux/mm.h | 1 +
mm/hwpoison-inject.c | 2 +-
mm/madvise.c | 2 +-
mm/memory-failure.c | 12 ++++++++++++
6 files changed, 18 insertions(+), 4 deletions(-)

--- a/Documentation/vm/hwpoison.rst
+++ b/Documentation/vm/hwpoison.rst
@@ -120,7 +120,8 @@ Testing
unpoison-pfn
Software-unpoison page at PFN echoed into this file. This way
a page can be reused again. This only works for Linux
- injected failures, not for real memory failures.
+ injected failures, not for real memory failures. Once any hardware
+ memory failure happens, this feature is disabled.

Note these injection interfaces are not stable and might change between
kernel versions
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -558,7 +558,7 @@ static ssize_t hard_offline_page_store(s
if (kstrtoull(buf, 0, &pfn) < 0)
return -EINVAL;
pfn >>= PAGE_SHIFT;
- ret = memory_failure(pfn, 0);
+ ret = memory_failure(pfn, MF_SW_SIMULATED);
if (ret == -EOPNOTSUPP)
ret = 0;
return ret ? ret : count;
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3188,6 +3188,7 @@ enum mf_flags {
MF_MUST_KILL = 1 << 2,
MF_SOFT_OFFLINE = 1 << 3,
MF_UNPOISON = 1 << 4,
+ MF_SW_SIMULATED = 1 << 5,
};
extern int memory_failure(unsigned long pfn, int flags);
extern void memory_failure_queue(unsigned long pfn, int flags);
--- a/mm/hwpoison-inject.c
+++ b/mm/hwpoison-inject.c
@@ -48,7 +48,7 @@ static int hwpoison_inject(void *data, u

inject:
pr_info("Injecting memory failure at pfn %#lx\n", pfn);
- err = memory_failure(pfn, 0);
+ err = memory_failure(pfn, MF_SW_SIMULATED);
return (err == -EOPNOTSUPP) ? 0 : err;
}

--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -1101,7 +1101,7 @@ static int madvise_inject_error(int beha
} else {
pr_info("Injecting memory failure for pfn %#lx at process virtual address %#lx\n",
pfn, start);
- ret = memory_failure(pfn, MF_COUNT_INCREASED);
+ ret = memory_failure(pfn, MF_COUNT_INCREASED | MF_SW_SIMULATED);
if (ret == -EOPNOTSUPP)
ret = 0;
}
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -68,6 +68,8 @@ int sysctl_memory_failure_recovery __rea

atomic_long_t num_poisoned_pages __read_mostly = ATOMIC_LONG_INIT(0);

+static bool hw_memory_failure __read_mostly = false;
+
static bool __page_handle_poison(struct page *page)
{
int ret;
@@ -1780,6 +1782,9 @@ int memory_failure(unsigned long pfn, in

mutex_lock(&mf_mutex);

+ if (!(flags & MF_SW_SIMULATED))
+ hw_memory_failure = true;
+
p = pfn_to_online_page(pfn);
if (!p) {
res = arch_memory_failure(pfn, flags);
@@ -2138,6 +2143,13 @@ int unpoison_memory(unsigned long pfn)

mutex_lock(&mf_mutex);

+ if (hw_memory_failure) {
+ unpoison_pr_info("Unpoison: Disabled after HW memory failure %#lx\n",
+ pfn, &unpoison_rs);
+ ret = -EOPNOTSUPP;
+ goto unlock_mutex;
+ }
+
if (!PageHWPoison(p)) {
unpoison_pr_info("Unpoison: Page was already unpoisoned %#lx\n",
pfn, &unpoison_rs);