* [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 [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 2:16 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
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox