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Subject[PATCH] mm/memory-failure: don't allow to unpoison hw corrupted page
Date
Currently unpoison_memory(unsigned long pfn) is designed for soft
poison(hwpoison-inject) only. Unpoisoning a hardware corrupted page
puts page back buddy only, this leads BUG during accessing on the
corrupted KPTE.

Do not allow to unpoison hardware corrupted page in unpoison_memory()
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

Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
---
mm/memory-failure.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index b85661cbdc4a..ec49571924f4 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -2090,6 +2090,7 @@ int unpoison_memory(unsigned long pfn)
{
struct page *page;
struct page *p;
+ pte_t *kpte;
int ret = -EBUSY;
int freeit = 0;
static DEFINE_RATELIMIT_STATE(unpoison_rs, DEFAULT_RATELIMIT_INTERVAL,
@@ -2101,6 +2102,13 @@ int unpoison_memory(unsigned long pfn)
p = pfn_to_page(pfn);
page = compound_head(p);

+ kpte = virt_to_kpte((unsigned long)page_to_virt(p));
+ if (kpte && !pte_present(*kpte)) {
+ unpoison_pr_info("Unpoison: Page was hardware poisoned %#lx\n",
+ pfn, &unpoison_rs);
+ return -EPERM;
+ }
+
mutex_lock(&mf_mutex);

if (!PageHWPoison(p)) {
--
2.20.1
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