* [PATCH v3 0/1] mm/memory-failure: don't allow to unpoison hw corrupted page
@ 2022-06-10 11:46 zhenwei pi
2022-06-10 11:46 ` [PATCH v3 1/1] " zhenwei pi
0 siblings, 1 reply; 6+ messages in thread
From: zhenwei pi @ 2022-06-10 11:46 UTC (permalink / raw)
To: pizhenwei, naoya.horiguchi, akpm; +Cc: linux-mm, linux-kernel
v2 -> v3:
- David pointed out that virt_to_kpte() is broken(no pmd_large() test
on a PMD), so drop this API in this patch, walk kmap instead.
v1 -> v2:
- this change gets protected by mf_mutex
- use -EOPNOTSUPP instead of -EPERM
v1:
- check KPTE to avoid to unpoison hardware corrupted page
zhenwei pi (1):
mm/memory-failure: don't allow to unpoison hw corrupted page
mm/memory-failure.c | 59 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 59 insertions(+)
--
2.20.1
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH v3 1/1] mm/memory-failure: don't allow to unpoison hw corrupted page
2022-06-10 11:46 [PATCH v3 0/1] mm/memory-failure: don't allow to unpoison hw corrupted page zhenwei pi
@ 2022-06-10 11:46 ` zhenwei pi
2022-06-10 12:12 ` David Hildenbrand
0 siblings, 1 reply; 6+ messages in thread
From: zhenwei pi @ 2022-06-10 11:46 UTC (permalink / raw)
To: pizhenwei, naoya.horiguchi, akpm
Cc: linux-mm, linux-kernel, David Hildenbrand
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.
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
Fixes: 847ce401df392 ("HWPOISON: Add unpoisoning support")
Fixes: 17fae1294ad9d ("x86/{mce,mm}: Unmap the entire page if the whole page is affected and poisoned")
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
---
mm/memory-failure.c | 59 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 59 insertions(+)
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index b85661cbdc4a..3124f428302c 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -2068,6 +2068,58 @@ static int __init memory_failure_init(void)
}
core_initcall(memory_failure_init);
+/*
+ * Unpoisoning a hardware corrupted page with *NOT PRESENT* KPTE leads panic.
+ * Test a page is valid in the kernel mapping.
+ */
+static bool kmap_valid(struct page *page)
+{
+ unsigned long addr = (unsigned long)page_to_virt(page);
+ pgd_t *pgd;
+ p4d_t *p4d;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte;
+
+ pgd = pgd_offset_k(addr);
+ if (pgd_none(*pgd))
+ return false;
+ if (pgd_leaf(*pgd))
+ return true;
+ if (pgd_bad(*pgd))
+ return false;
+
+ p4d = p4d_offset(pgd, addr);
+ if (p4d_none(*p4d))
+ return false;
+ if (p4d_leaf(*p4d))
+ return true;
+ if (p4d_bad(*p4d))
+ return false;
+
+ pud = pud_offset(p4d, addr);
+ if (pud_none(*pud))
+ return false;
+ if (pud_leaf(*pud))
+ return true;
+ if (pud_bad(*pud))
+ return false;
+
+ pmd = pmd_offset(pud, addr);
+ if (pmd_none(*pmd))
+ return false;
+ if (pmd_leaf(*pmd))
+ return true;
+ if (pmd_bad(*pmd))
+ return false;
+
+ pte = pte_offset_map(pmd, addr);
+ if (pte_none(*pte) || !pte_present(*pte))
+ return false;
+
+ return true;
+}
+
#define unpoison_pr_info(fmt, pfn, rs) \
({ \
if (__ratelimit(rs)) \
@@ -2109,6 +2161,13 @@ int unpoison_memory(unsigned long pfn)
goto unlock_mutex;
}
+ if (!kmap_valid(page)) {
+ unpoison_pr_info("Unpoison: Page was hardware poisoned %#lx\n",
+ pfn, &unpoison_rs);
+ ret = -EOPNOTSUPP;
+ goto unlock_mutex;
+ }
+
if (page_count(page) > 1) {
unpoison_pr_info("Unpoison: Someone grabs the hwpoison page %#lx\n",
pfn, &unpoison_rs);
--
2.20.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH v3 1/1] mm/memory-failure: don't allow to unpoison hw corrupted page
2022-06-10 11:46 ` [PATCH v3 1/1] " zhenwei pi
@ 2022-06-10 12:12 ` David Hildenbrand
2022-06-14 0:22 ` zhenwei pi
2022-06-14 2:16 ` Miaohe Lin
0 siblings, 2 replies; 6+ messages in thread
From: David Hildenbrand @ 2022-06-10 12:12 UTC (permalink / raw)
To: zhenwei pi, naoya.horiguchi, akpm; +Cc: linux-mm, linux-kernel
On 10.06.22 13:46, zhenwei pi wrote:
> 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.
>
> 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
>
> Fixes: 847ce401df392 ("HWPOISON: Add unpoisoning support")
> Fixes: 17fae1294ad9d ("x86/{mce,mm}: Unmap the entire page if the whole page is affected and poisoned")
> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
> Cc: David Hildenbrand <david@redhat.com>
> Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
> ---
> mm/memory-failure.c | 59 +++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 59 insertions(+)
>
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index b85661cbdc4a..3124f428302c 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -2068,6 +2068,58 @@ static int __init memory_failure_init(void)
> }
> core_initcall(memory_failure_init);
>
> +/*
> + * Unpoisoning a hardware corrupted page with *NOT PRESENT* KPTE leads panic.
> + * Test a page is valid in the kernel mapping.
> + */
> +static bool kmap_valid(struct page *page)
> +{
> + unsigned long addr = (unsigned long)page_to_virt(page);
> + pgd_t *pgd;
> + p4d_t *p4d;
> + pud_t *pud;
> + pmd_t *pmd;
> + pte_t *pte;
> +
> + pgd = pgd_offset_k(addr);
> + if (pgd_none(*pgd))
> + return false;
> + if (pgd_leaf(*pgd))
> + return true;
> + if (pgd_bad(*pgd))
> + return false;
> +
> + p4d = p4d_offset(pgd, addr);
> + if (p4d_none(*p4d))
> + return false;
> + if (p4d_leaf(*p4d))
> + return true;
> + if (p4d_bad(*p4d))
> + return false;
> +
> + pud = pud_offset(p4d, addr);
> + if (pud_none(*pud))
> + return false;
> + if (pud_leaf(*pud))
> + return true;
> + if (pud_bad(*pud))
> + return false;
> +
> + pmd = pmd_offset(pud, addr);
> + if (pmd_none(*pmd))
> + return false;
> + if (pmd_leaf(*pmd))
> + return true;
> + if (pmd_bad(*pmd))
> + return false;
> +
> + pte = pte_offset_map(pmd, addr);
> + if (pte_none(*pte) || !pte_present(*pte))
> + return false;
> +
> + return true;
> +}
> +
> #define unpoison_pr_info(fmt, pfn, rs) \
> ({ \
> if (__ratelimit(rs)) \
> @@ -2109,6 +2161,13 @@ int unpoison_memory(unsigned long pfn)
> goto unlock_mutex;
> }
>
> + if (!kmap_valid(page)) {
> + unpoison_pr_info("Unpoison: Page was hardware poisoned %#lx\n",
> + pfn, &unpoison_rs);
> + ret = -EOPNOTSUPP;
> + goto unlock_mutex;
> + }
> +
> if (page_count(page) > 1) {
> unpoison_pr_info("Unpoison: Someone grabs the hwpoison page %#lx\n",
> pfn, &unpoison_rs);
I really prefer just disabling the unpoisioning mechanism in case there
is a real hw injected error.
--
Thanks,
David / dhildenb
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Re: [PATCH v3 1/1] mm/memory-failure: don't allow to unpoison hw corrupted page
2022-06-10 12:12 ` David Hildenbrand
@ 2022-06-14 0:22 ` zhenwei pi
2022-06-14 0:41 ` HORIGUCHI NAOYA(堀口 直也)
2022-06-14 2:16 ` Miaohe Lin
1 sibling, 1 reply; 6+ messages in thread
From: zhenwei pi @ 2022-06-14 0:22 UTC (permalink / raw)
To: naoya.horiguchi, akpm; +Cc: linux-mm, linux-kernel, David Hildenbrand
On 6/10/22 20:12, David Hildenbrand wrote:
> On 10.06.22 13:46, zhenwei pi wrote:
>> 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.
>>
>> 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
>>
>> Fixes: 847ce401df392 ("HWPOISON: Add unpoisoning support")
>> Fixes: 17fae1294ad9d ("x86/{mce,mm}: Unmap the entire page if the whole page is affected and poisoned")
>> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
>> Cc: David Hildenbrand <david@redhat.com>
>> Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
>> ---
>> mm/memory-failure.c | 59 +++++++++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 59 insertions(+)
>>
>> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
>> index b85661cbdc4a..3124f428302c 100644
>> --- a/mm/memory-failure.c
>> +++ b/mm/memory-failure.c
>> @@ -2068,6 +2068,58 @@ static int __init memory_failure_init(void)
>> }
>> core_initcall(memory_failure_init);
>>
>> +/*
>> + * Unpoisoning a hardware corrupted page with *NOT PRESENT* KPTE leads panic.
>> + * Test a page is valid in the kernel mapping.
>> + */
>> +static bool kmap_valid(struct page *page)
>> +{
>> + unsigned long addr = (unsigned long)page_to_virt(page);
>> + pgd_t *pgd;
>> + p4d_t *p4d;
>> + pud_t *pud;
>> + pmd_t *pmd;
>> + pte_t *pte;
>> +
>> + pgd = pgd_offset_k(addr);
>> + if (pgd_none(*pgd))
>> + return false;
>> + if (pgd_leaf(*pgd))
>> + return true;
>> + if (pgd_bad(*pgd))
>> + return false;
>> +
>> + p4d = p4d_offset(pgd, addr);
>> + if (p4d_none(*p4d))
>> + return false;
>> + if (p4d_leaf(*p4d))
>> + return true;
>> + if (p4d_bad(*p4d))
>> + return false;
>> +
>> + pud = pud_offset(p4d, addr);
>> + if (pud_none(*pud))
>> + return false;
>> + if (pud_leaf(*pud))
>> + return true;
>> + if (pud_bad(*pud))
>> + return false;
>> +
>> + pmd = pmd_offset(pud, addr);
>> + if (pmd_none(*pmd))
>> + return false;
>> + if (pmd_leaf(*pmd))
>> + return true;
>> + if (pmd_bad(*pmd))
>> + return false;
>> +
>> + pte = pte_offset_map(pmd, addr);
>> + if (pte_none(*pte) || !pte_present(*pte))
>> + return false;
>> +
>> + return true;
>> +}
>> +
>> #define unpoison_pr_info(fmt, pfn, rs) \
>> ({ \
>> if (__ratelimit(rs)) \
>> @@ -2109,6 +2161,13 @@ int unpoison_memory(unsigned long pfn)
>> goto unlock_mutex;
>> }
>>
>> + if (!kmap_valid(page)) {
>> + unpoison_pr_info("Unpoison: Page was hardware poisoned %#lx\n",
>> + pfn, &unpoison_rs);
>> + ret = -EOPNOTSUPP;
>> + goto unlock_mutex;
>> + }
>> +
>> if (page_count(page) > 1) {
>> unpoison_pr_info("Unpoison: Someone grabs the hwpoison page %#lx\n",
>> pfn, &unpoison_rs);
>
> I really prefer just disabling the unpoisioning mechanism in case there
> is a real hw injected error.
>
Hi, Naoya & Andrew
What is your opinion?
--
zhenwei pi
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Re: [PATCH v3 1/1] mm/memory-failure: don't allow to unpoison hw corrupted page
2022-06-14 0:22 ` zhenwei pi
@ 2022-06-14 0:41 ` HORIGUCHI NAOYA(堀口 直也)
0 siblings, 0 replies; 6+ messages in thread
From: HORIGUCHI NAOYA(堀口 直也) @ 2022-06-14 0:41 UTC (permalink / raw)
To: zhenwei pi; +Cc: akpm, linux-mm, linux-kernel, David Hildenbrand
On Tue, Jun 14, 2022 at 08:22:10AM +0800, zhenwei pi wrote:
>
>
> On 6/10/22 20:12, David Hildenbrand wrote:
> > On 10.06.22 13:46, zhenwei pi wrote:
> > > 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.
> > >
> > > 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
> > >
> > > Fixes: 847ce401df392 ("HWPOISON: Add unpoisoning support")
> > > Fixes: 17fae1294ad9d ("x86/{mce,mm}: Unmap the entire page if the whole page is affected and poisoned")
> > > Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
> > > Cc: David Hildenbrand <david@redhat.com>
> > > Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
> > > ---
> > > mm/memory-failure.c | 59 +++++++++++++++++++++++++++++++++++++++++++++
> > > 1 file changed, 59 insertions(+)
> > >
> > > diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> > > index b85661cbdc4a..3124f428302c 100644
> > > --- a/mm/memory-failure.c
> > > +++ b/mm/memory-failure.c
> > > @@ -2068,6 +2068,58 @@ static int __init memory_failure_init(void)
> > > }
> > > core_initcall(memory_failure_init);
> > > +/*
> > > + * Unpoisoning a hardware corrupted page with *NOT PRESENT* KPTE leads panic.
> > > + * Test a page is valid in the kernel mapping.
> > > + */
> > > +static bool kmap_valid(struct page *page)
> > > +{
> > > + unsigned long addr = (unsigned long)page_to_virt(page);
> > > + pgd_t *pgd;
> > > + p4d_t *p4d;
> > > + pud_t *pud;
> > > + pmd_t *pmd;
> > > + pte_t *pte;
> > > +
> > > + pgd = pgd_offset_k(addr);
> > > + if (pgd_none(*pgd))
> > > + return false;
> > > + if (pgd_leaf(*pgd))
> > > + return true;
> > > + if (pgd_bad(*pgd))
> > > + return false;
> > > +
> > > + p4d = p4d_offset(pgd, addr);
> > > + if (p4d_none(*p4d))
> > > + return false;
> > > + if (p4d_leaf(*p4d))
> > > + return true;
> > > + if (p4d_bad(*p4d))
> > > + return false;
> > > +
> > > + pud = pud_offset(p4d, addr);
> > > + if (pud_none(*pud))
> > > + return false;
> > > + if (pud_leaf(*pud))
> > > + return true;
> > > + if (pud_bad(*pud))
> > > + return false;
> > > +
> > > + pmd = pmd_offset(pud, addr);
> > > + if (pmd_none(*pmd))
> > > + return false;
> > > + if (pmd_leaf(*pmd))
> > > + return true;
> > > + if (pmd_bad(*pmd))
> > > + return false;
> > > +
> > > + pte = pte_offset_map(pmd, addr);
> > > + if (pte_none(*pte) || !pte_present(*pte))
> > > + return false;
> > > +
> > > + return true;
> > > +}
> > > +
> > > #define unpoison_pr_info(fmt, pfn, rs) \
> > > ({ \
> > > if (__ratelimit(rs)) \
> > > @@ -2109,6 +2161,13 @@ int unpoison_memory(unsigned long pfn)
> > > goto unlock_mutex;
> > > }
> > > + if (!kmap_valid(page)) {
> > > + unpoison_pr_info("Unpoison: Page was hardware poisoned %#lx\n",
> > > + pfn, &unpoison_rs);
> > > + ret = -EOPNOTSUPP;
> > > + goto unlock_mutex;
> > > + }
> > > +
> > > if (page_count(page) > 1) {
> > > unpoison_pr_info("Unpoison: Someone grabs the hwpoison page %#lx\n",
> > > pfn, &unpoison_rs);
> >
> > I really prefer just disabling the unpoisioning mechanism in case there
> > is a real hw injected error.
> >
>
> Hi, Naoya & Andrew
>
> What is your opinion?
Disabling unpoison when a real HW error happens is fine to me. When you
write the patch, could you add a few sentences about the new behavior to
the unpoison-pfn section in Documentation/vm/hwpoison.rst?
Thanks,
Naoya Horiguchi
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v3 1/1] mm/memory-failure: don't allow to unpoison hw corrupted page
2022-06-10 12:12 ` David Hildenbrand
2022-06-14 0:22 ` zhenwei pi
@ 2022-06-14 2:16 ` Miaohe Lin
1 sibling, 0 replies; 6+ messages in thread
From: Miaohe Lin @ 2022-06-14 2:16 UTC (permalink / raw)
To: David Hildenbrand
Cc: linux-mm, linux-kernel, zhenwei pi, naoya.horiguchi, akpm
On 2022/6/10 20:12, David Hildenbrand wrote:
>
> I really prefer just disabling the unpoisioning mechanism in case there
> is a real hw injected error.
IMHO, this would be a simple solution that also works on the arches that does not unmap
the kernel mapping when a page is hardware corrupted.
Thanks!
>
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2022-06-14 2:37 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-06-10 11:46 [PATCH v3 0/1] mm/memory-failure: don't allow to unpoison hw corrupted page zhenwei pi
2022-06-10 11:46 ` [PATCH v3 1/1] " zhenwei pi
2022-06-10 12:12 ` David Hildenbrand
2022-06-14 0:22 ` zhenwei pi
2022-06-14 0:41 ` HORIGUCHI NAOYA(堀口 直也)
2022-06-14 2:16 ` Miaohe Lin
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