| Message ID | 20200413010342.771-1-longpeng2@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v5] mm/hugetlb: fix a addressing exception caused by huge_pte_offset | expand |
On 4/12/20 6:03 PM, Longpeng(Mike) wrote: > From: Longpeng <longpeng2@huawei.com> > > Our machine encountered a panic(addressing exception) after run > for a long time and the calltrace is: > RIP: 0010:[<ffffffff9dff0587>] [<ffffffff9dff0587>] hugetlb_fault+0x307/0xbe0 > RSP: 0018:ffff9567fc27f808 EFLAGS: 00010286 > RAX: e800c03ff1258d48 RBX: ffffd3bb003b69c0 RCX: e800c03ff1258d48 > RDX: 17ff3fc00eda72b7 RSI: 00003ffffffff000 RDI: e800c03ff1258d48 > RBP: ffff9567fc27f8c8 R08: e800c03ff1258d48 R09: 0000000000000080 > R10: ffffaba0704c22a8 R11: 0000000000000001 R12: ffff95c87b4b60d8 > R13: 00005fff00000000 R14: 0000000000000000 R15: ffff9567face8074 > FS: 00007fe2d9ffb700(0000) GS:ffff956900e40000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: ffffd3bb003b69c0 CR3: 000000be67374000 CR4: 00000000003627e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > [<ffffffff9df9b71b>] ? unlock_page+0x2b/0x30 > [<ffffffff9dff04a2>] ? hugetlb_fault+0x222/0xbe0 > [<ffffffff9dff1405>] follow_hugetlb_page+0x175/0x540 > [<ffffffff9e15b825>] ? cpumask_next_and+0x35/0x50 > [<ffffffff9dfc7230>] __get_user_pages+0x2a0/0x7e0 > [<ffffffff9dfc648d>] __get_user_pages_unlocked+0x15d/0x210 > [<ffffffffc068cfc5>] __gfn_to_pfn_memslot+0x3c5/0x460 [kvm] > [<ffffffffc06b28be>] try_async_pf+0x6e/0x2a0 [kvm] > [<ffffffffc06b4b41>] tdp_page_fault+0x151/0x2d0 [kvm] > ... > [<ffffffffc06a6f90>] kvm_arch_vcpu_ioctl_run+0x330/0x490 [kvm] > [<ffffffffc068d919>] kvm_vcpu_ioctl+0x309/0x6d0 [kvm] > [<ffffffff9deaa8c2>] ? dequeue_signal+0x32/0x180 > [<ffffffff9deae34d>] ? do_sigtimedwait+0xcd/0x230 > [<ffffffff9e03aed0>] do_vfs_ioctl+0x3f0/0x540 > [<ffffffff9e03b0c1>] SyS_ioctl+0xa1/0xc0 > [<ffffffff9e53879b>] system_call_fastpath+0x22/0x27 > > For 1G hugepages, huge_pte_offset() wants to return NULL or pudp, but it > may return a wrong 'pmdp' if there is a race. Please look at the following > code snippet: > ... > pud = pud_offset(p4d, addr); > if (sz != PUD_SIZE && pud_none(*pud)) > return NULL; > /* hugepage or swap? */ > if (pud_huge(*pud) || !pud_present(*pud)) > return (pte_t *)pud; > > pmd = pmd_offset(pud, addr); > if (sz != PMD_SIZE && pmd_none(*pmd)) > return NULL; > /* hugepage or swap? */ > if (pmd_huge(*pmd) || !pmd_present(*pmd)) > return (pte_t *)pmd; > ... > > The following sequence would trigger this bug: > 1. CPU0: sz = PUD_SIZE and *pud = 0 , continue > 1. CPU0: "pud_huge(*pud)" is false > 2. CPU1: calling hugetlb_no_page and set *pud to xxxx8e7(PRESENT) > 3. CPU0: "!pud_present(*pud)" is false, continue > 4. CPU0: pmd = pmd_offset(pud, addr) and maybe return a wrong pmdp > However, we want CPU0 to return NULL or pudp in this case. > > We must make sure there is exactly one dereference of pud and pmd. > > Cc: Mike Kravetz <mike.kravetz@oracle.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Jason Gunthorpe <jgg@ziepe.ca> > Cc: Matthew Wilcox <willy@infradead.org> > Cc: Sean Christopherson <sean.j.christopherson@intel.com> > Cc: stable@vger.kernel.org > Signed-off-by: Longpeng <longpeng2@huawei.com> Thank you for continuing to work this! Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
On Mon, Apr 13, 2020 at 09:03:42AM +0800, Longpeng(Mike) wrote: > From: Longpeng <longpeng2@huawei.com> > > Our machine encountered a panic(addressing exception) after run > for a long time and the calltrace is: > RIP: 0010:[<ffffffff9dff0587>] [<ffffffff9dff0587>] hugetlb_fault+0x307/0xbe0 > RSP: 0018:ffff9567fc27f808 EFLAGS: 00010286 > RAX: e800c03ff1258d48 RBX: ffffd3bb003b69c0 RCX: e800c03ff1258d48 > RDX: 17ff3fc00eda72b7 RSI: 00003ffffffff000 RDI: e800c03ff1258d48 > RBP: ffff9567fc27f8c8 R08: e800c03ff1258d48 R09: 0000000000000080 > R10: ffffaba0704c22a8 R11: 0000000000000001 R12: ffff95c87b4b60d8 > R13: 00005fff00000000 R14: 0000000000000000 R15: ffff9567face8074 > FS: 00007fe2d9ffb700(0000) GS:ffff956900e40000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: ffffd3bb003b69c0 CR3: 000000be67374000 CR4: 00000000003627e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > [<ffffffff9df9b71b>] ? unlock_page+0x2b/0x30 > [<ffffffff9dff04a2>] ? hugetlb_fault+0x222/0xbe0 > [<ffffffff9dff1405>] follow_hugetlb_page+0x175/0x540 > [<ffffffff9e15b825>] ? cpumask_next_and+0x35/0x50 > [<ffffffff9dfc7230>] __get_user_pages+0x2a0/0x7e0 > [<ffffffff9dfc648d>] __get_user_pages_unlocked+0x15d/0x210 > [<ffffffffc068cfc5>] __gfn_to_pfn_memslot+0x3c5/0x460 [kvm] > [<ffffffffc06b28be>] try_async_pf+0x6e/0x2a0 [kvm] > [<ffffffffc06b4b41>] tdp_page_fault+0x151/0x2d0 [kvm] > ... > [<ffffffffc06a6f90>] kvm_arch_vcpu_ioctl_run+0x330/0x490 [kvm] > [<ffffffffc068d919>] kvm_vcpu_ioctl+0x309/0x6d0 [kvm] > [<ffffffff9deaa8c2>] ? dequeue_signal+0x32/0x180 > [<ffffffff9deae34d>] ? do_sigtimedwait+0xcd/0x230 > [<ffffffff9e03aed0>] do_vfs_ioctl+0x3f0/0x540 > [<ffffffff9e03b0c1>] SyS_ioctl+0xa1/0xc0 > [<ffffffff9e53879b>] system_call_fastpath+0x22/0x27 > > For 1G hugepages, huge_pte_offset() wants to return NULL or pudp, but it > may return a wrong 'pmdp' if there is a race. Please look at the following > code snippet: > ... > pud = pud_offset(p4d, addr); > if (sz != PUD_SIZE && pud_none(*pud)) > return NULL; > /* hugepage or swap? */ > if (pud_huge(*pud) || !pud_present(*pud)) > return (pte_t *)pud; > > pmd = pmd_offset(pud, addr); > if (sz != PMD_SIZE && pmd_none(*pmd)) > return NULL; > /* hugepage or swap? */ > if (pmd_huge(*pmd) || !pmd_present(*pmd)) > return (pte_t *)pmd; > ... > > The following sequence would trigger this bug: > 1. CPU0: sz = PUD_SIZE and *pud = 0 , continue > 1. CPU0: "pud_huge(*pud)" is false > 2. CPU1: calling hugetlb_no_page and set *pud to xxxx8e7(PRESENT) > 3. CPU0: "!pud_present(*pud)" is false, continue > 4. CPU0: pmd = pmd_offset(pud, addr) and maybe return a wrong pmdp > However, we want CPU0 to return NULL or pudp in this case. > > We must make sure there is exactly one dereference of pud and pmd. > > Cc: Mike Kravetz <mike.kravetz@oracle.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Jason Gunthorpe <jgg@ziepe.ca> > Cc: Matthew Wilcox <willy@infradead.org> > Cc: Sean Christopherson <sean.j.christopherson@intel.com> > Cc: stable@vger.kernel.org > Signed-off-by: Longpeng <longpeng2@huawei.com> > --- > v4 -> v5: > fix a bug of on i386 > v3 -> v4: > fix a typo s/p4g/p4d. [Jason] > v2 -> v3: > make sure p4d/pud/pmd be dereferenced once. [Jason] > > --- > mm/hugetlb.c | 14 ++++++++------ > 1 file changed, 8 insertions(+), 6 deletions(-) Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Jason
Hi
[This is an automated email]
This commit has been processed because it contains a -stable tag.
The stable tag indicates that it's relevant for the following trees: all
The bot has tested the following trees: v5.6.5, v5.5.18, v5.4.33, v4.19.116, v4.14.176, v4.9.219, v4.4.219.
v5.6.5: Build OK!
v5.5.18: Build OK!
v5.4.33: Build OK!
v4.19.116: Build OK!
v4.14.176: Build OK!
v4.9.219: Failed to apply! Possible dependencies:
166f61b9435a ("mm: codgin-style fixes")
505a60e22560 ("asm-generic: introduce 5level-fixup.h")
82b0f8c39a38 ("mm: join struct fault_env and vm_fault")
953c66c2b22a ("mm: THP page cache support for ppc64")
c2febafc6773 ("mm: convert generic code to 5-level paging")
fd60775aea80 ("mm, thp: avoid unlikely branches for split_huge_pmd")
v4.4.219: Failed to apply! Possible dependencies:
01c8f1c44b83 ("mm, dax, gpu: convert vm_insert_mixed to pfn_t")
0e749e54244e ("dax: increase granularity of dax_clear_blocks() operations")
166f61b9435a ("mm: codgin-style fixes")
34c0fd540e79 ("mm, dax, pmem: introduce pfn_t")
505a60e22560 ("asm-generic: introduce 5level-fixup.h")
52db400fcd50 ("pmem, dax: clean up clear_pmem()")
5c6a84a3f455 ("mm/kasan: Switch to using __pa_symbol and lm_alias")
82b0f8c39a38 ("mm: join struct fault_env and vm_fault")
9973c98ecfda ("dax: add support for fsync/sync")
aac453635549 ("mm, oom: introduce oom reaper")
ac401cc78242 ("dax: New fault locking")
b2e0d1625e19 ("dax: fix lifetime of in-kernel dax mappings with dax_map_atomic()")
bae473a423f6 ("mm: introduce fault_env")
bc2466e42573 ("dax: Use radix tree entry lock to protect cow faults")
c2febafc6773 ("mm: convert generic code to 5-level paging")
e4b274915863 ("DAX: move RADIX_DAX_ definitions to dax.c")
f9fe48bece3a ("dax: support dirty DAX entries in radix tree")
NOTE: The patch will not be queued to stable trees until it is upstream.
How should we proceed with this patch?
This bug was introduced by commit 9b19df292c666b57c407fed2496827c6aba05be2
("mm/hugetlb.c: make huge_pte_offset() consistent and document behaviour"), but
v4.4.219 and v4.9.219 haven't included it, so we needn't to apply my patch to
these two stable trees.
On 2020/4/22 3:56, Sasha Levin wrote:
> Hi
>
> [This is an automated email]
>
> This commit has been processed because it contains a -stable tag.
> The stable tag indicates that it's relevant for the following trees: all
>
> The bot has tested the following trees: v5.6.5, v5.5.18, v5.4.33, v4.19.116, v4.14.176, v4.9.219, v4.4.219.
>
> v5.6.5: Build OK!
> v5.5.18: Build OK!
> v5.4.33: Build OK!
> v4.19.116: Build OK!
> v4.14.176: Build OK!
> v4.9.219: Failed to apply! Possible dependencies:
> 166f61b9435a ("mm: codgin-style fixes")
> 505a60e22560 ("asm-generic: introduce 5level-fixup.h")
> 82b0f8c39a38 ("mm: join struct fault_env and vm_fault")
> 953c66c2b22a ("mm: THP page cache support for ppc64")
> c2febafc6773 ("mm: convert generic code to 5-level paging")
> fd60775aea80 ("mm, thp: avoid unlikely branches for split_huge_pmd")
>
> v4.4.219: Failed to apply! Possible dependencies:
> 01c8f1c44b83 ("mm, dax, gpu: convert vm_insert_mixed to pfn_t")
> 0e749e54244e ("dax: increase granularity of dax_clear_blocks() operations")
> 166f61b9435a ("mm: codgin-style fixes")
> 34c0fd540e79 ("mm, dax, pmem: introduce pfn_t")
> 505a60e22560 ("asm-generic: introduce 5level-fixup.h")
> 52db400fcd50 ("pmem, dax: clean up clear_pmem()")
> 5c6a84a3f455 ("mm/kasan: Switch to using __pa_symbol and lm_alias")
> 82b0f8c39a38 ("mm: join struct fault_env and vm_fault")
> 9973c98ecfda ("dax: add support for fsync/sync")
> aac453635549 ("mm, oom: introduce oom reaper")
> ac401cc78242 ("dax: New fault locking")
> b2e0d1625e19 ("dax: fix lifetime of in-kernel dax mappings with dax_map_atomic()")
> bae473a423f6 ("mm: introduce fault_env")
> bc2466e42573 ("dax: Use radix tree entry lock to protect cow faults")
> c2febafc6773 ("mm: convert generic code to 5-level paging")
> e4b274915863 ("DAX: move RADIX_DAX_ definitions to dax.c")
> f9fe48bece3a ("dax: support dirty DAX entries in radix tree")
>
>
> NOTE: The patch will not be queued to stable trees until it is upstream.
>
> How should we proceed with this patch?
>
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index cd45915..bcabbe0 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -5365,8 +5365,8 @@ pte_t *huge_pte_offset(struct mm_struct *mm, { pgd_t *pgd; p4d_t *p4d; - pud_t *pud; - pmd_t *pmd; + pud_t *pud, pud_entry; + pmd_t *pmd, pmd_entry; pgd = pgd_offset(mm, addr); if (!pgd_present(*pgd)) @@ -5376,17 +5376,19 @@ pte_t *huge_pte_offset(struct mm_struct *mm, return NULL; pud = pud_offset(p4d, addr); - if (sz != PUD_SIZE && pud_none(*pud)) + pud_entry = READ_ONCE(*pud); + if (sz != PUD_SIZE && pud_none(pud_entry)) return NULL; /* hugepage or swap? */ - if (pud_huge(*pud) || !pud_present(*pud)) + if (pud_huge(pud_entry) || !pud_present(pud_entry)) return (pte_t *)pud; pmd = pmd_offset(pud, addr); - if (sz != PMD_SIZE && pmd_none(*pmd)) + pmd_entry = READ_ONCE(*pmd); + if (sz != PMD_SIZE && pmd_none(pmd_entry)) return NULL; /* hugepage or swap? */ - if (pmd_huge(*pmd) || !pmd_present(*pmd)) + if (pmd_huge(pmd_entry) || !pmd_present(pmd_entry)) return (pte_t *)pmd; return NULL;