| Message ID | 20211221074908.3910286-1-liushixin2@huawei.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [-next] mm/hwpoison: clear MF_COUNT_INCREASED before retrying get_any_page() | expand |
On Tue, Dec 21, 2021 at 03:49:08PM +0800, Liu Shixin wrote: > Hulk Robot reported a panic in put_page_testzero() when testing madvise() > with MADV_SOFT_OFFLINE. The BUG() is triggered when retrying get_any_page(). > This is because we keep MF_COUNT_INCREASED flag in second try but the refcnt > is not increased. > [...] > > Fixes: b94e02822deb ("mm,hwpoison: try to narrow window race for free pages") > Reported-by: Hulk Robot <hulkci@huawei.com> > Signed-off-by: Liu Shixin <liushixin2@huawei.com> Reviewed-by: Oscar Salvador <osalvador@suse.de>
On Tue, Dec 21, 2021 at 03:49:08PM +0800, Liu Shixin wrote: > Hulk Robot reported a panic in put_page_testzero() when testing madvise() > with MADV_SOFT_OFFLINE. The BUG() is triggered when retrying get_any_page(). > This is because we keep MF_COUNT_INCREASED flag in second try but the refcnt > is not increased. Hi Shixin, Thanks you for the report. I'm not still sure about the logic behind the bug. madvise(MADV_SOFT_OFFLINE) should not work on free pages because madvise_inject_error() pins the target page with get_user_pages_fast() (MF_COUNT_INCREASED means refcount is incremented by the caller). The retry logic can be called when soft_offline_free_page() fails, so the logic assumes that the target page is a free page. So why does clearing MF_COUNT_INCREASED affect and solve the issue? It seems to me that if soft_offline_page() is called on a free page with MF_COUNT_INCREASED set, then it's problematic itself. Thanks, Naoya Horiguchi > > page dumped because: VM_BUG_ON_PAGE(page_ref_count(page) == 0) > ------------[ cut here ]------------ > kernel BUG at include/linux/mm.h:737! > invalid opcode: 0000 [#1] PREEMPT SMP > CPU: 5 PID: 2135 Comm: sshd Tainted: G B 5.16.0-rc6-dirty #373 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 > RIP: 0010:release_pages+0x53f/0x840 > Code: 0c 01 4c 8d 60 ff e9 5b fb ff ff 48 c7 c6 d8 97 0c b3 4c 89 e7 48 83 05 0e 7b 3c 0c 01 e8 89 3d 04 00 48 83 05 11 7b 3c 0c 01 <0f> 0b 48 83 05 0f 7b 3c 0c 01 48 83 05 0f 7b 3c 0c 01 48 83 05f > RSP: 0018:ffffc900015a7bc0 EFLAGS: 00010002 > RAX: 000000000000003e RBX: ffffffffbace04c8 RCX: 0000000000000002 > RDX: 0000000000000000 RSI: 0000000000000001 RDI: 00000000ffffffff > RBP: ffff88817b9acd50 R08: 0000000000000000 R09: c0000000ffefffff > R10: 0000000000000001 R11: ffffc900015a79b0 R12: ffffea0005e1c900 > R13: ffffea0005e1de88 R14: 000000000000001f R15: ffff888100071000 > FS: 0000000000000000(0000) GS:ffff88842fb40000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f305e8de3d4 CR3: 000000017bb6f000 CR4: 00000000000006e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > <TASK> > free_pages_and_swap_cache+0x64/0x80 > tlb_flush_mmu+0x6f/0x220 > unmap_page_range+0xe6c/0x12c0 > unmap_single_vma+0x90/0x170 > unmap_vmas+0xc4/0x180 > exit_mmap+0xde/0x3a0 > mmput+0xa3/0x250 > do_exit+0x564/0x1470 > do_group_exit+0x3b/0x100 > __do_sys_exit_group+0x13/0x20 > __x64_sys_exit_group+0x16/0x20 > do_syscall_64+0x34/0x80 > entry_SYSCALL_64_after_hwframe+0x44/0xae > RIP: 0033:0x7f30625401d9 > Code: Unable to access opcode bytes at RIP 0x7f30625401af. > RSP: 002b:00007ffe391b0c88 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 > RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f30625401d9 > RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000001 > RBP: 00007f306283d838 R08: 000000000000003c R09: 00000000000000e7 > R10: fffffffffffffe30 R11: 0000000000000246 R12: 00007f306283d838 > R13: 00007f3062842e80 R14: 0000000000000000 R15: ffffaa4fb7932430 > </TASK> > Modules linked in: > ---[ end trace e99579b570fe0649 ]--- > RIP: 0010:release_pages+0x53f/0x840 > Code: 0c 01 4c 8d 60 ff e9 5b fb ff ff 48 c7 c6 d8 97 0c b3 4c 89 e7 48 83 05 0e 7b 3c 0c 01 e8 89 3d 04 00 48 83 05 11 7b 3c 0c 01 <0f> 0b 48 83 05 0f 7b 3c 0c 01 48 83 05 0f 7b 3c 0c 01 48 83 05f > RSP: 0018:ffffc900015a7bc0 EFLAGS: 00010002 > RAX: 000000000000003e RBX: ffffffffbace04c8 RCX: 0000000000000002 > RDX: 0000000000000000 RSI: 0000000000000001 RDI: 00000000ffffffff > RBP: ffff88817b9acd50 R08: 0000000000000000 R09: c0000000ffefffff > R10: 0000000000000001 R11: ffffc900015a79b0 R12: ffffea0005e1c900 > R13: ffffea0005e1de88 R14: 000000000000001f R15: ffff888100071000 > FS: 0000000000000000(0000) GS:ffff88842fb40000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f305e8de3d4 CR3: 000000017bb6f000 CR4: 00000000000006e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > Fixes: b94e02822deb ("mm,hwpoison: try to narrow window race for free pages") > Reported-by: Hulk Robot <hulkci@huawei.com> > Signed-off-by: Liu Shixin <liushixin2@huawei.com> > --- > mm/memory-failure.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index 68d9a35f8908..160526f83bcb 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -2288,6 +2288,7 @@ int soft_offline_page(unsigned long pfn, int flags) > } else if (ret == 0) { > if (soft_offline_free_page(page) && try_again) { > try_again = false; > + flags &= ~MF_COUNT_INCREASED; > goto retry; > } > } > -- > 2.25.1 >
On 2021/12/22 8:37, Naoya Horiguchi wrote: > On Tue, Dec 21, 2021 at 03:49:08PM +0800, Liu Shixin wrote: >> Hulk Robot reported a panic in put_page_testzero() when testing madvise() >> with MADV_SOFT_OFFLINE. The BUG() is triggered when retrying get_any_page(). >> This is because we keep MF_COUNT_INCREASED flag in second try but the refcnt >> is not increased. > Hi Shixin, > > Thanks you for the report. > > I'm not still sure about the logic behind the bug. > madvise(MADV_SOFT_OFFLINE) should not work on free pages because > madvise_inject_error() pins the target page with get_user_pages_fast() > (MF_COUNT_INCREASED means refcount is incremented by the caller). > The retry logic can be called when soft_offline_free_page() fails, so > the logic assumes that the target page is a free page. So why does > clearing MF_COUNT_INCREASED affect and solve the issue? > > It seems to me that if soft_offline_page() is called on a free page > with MF_COUNT_INCREASED set, then it's problematic itself. > > Thanks, > Naoya Horiguchi The page is not free when soft_offline_page() is called. In get_any_page(), if MF_COUNT_INCREASED is set and !HWPoisonHandlable(page), put_page() will be called firstly and then goto try_again. The page is freed in this period. Thanks, Liu Shixin >> page dumped because: VM_BUG_ON_PAGE(page_ref_count(page) == 0) >> ------------[ cut here ]------------ >> kernel BUG at include/linux/mm.h:737! >> invalid opcode: 0000 [#1] PREEMPT SMP >> CPU: 5 PID: 2135 Comm: sshd Tainted: G B 5.16.0-rc6-dirty #373 >> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 >> RIP: 0010:release_pages+0x53f/0x840 >> Code: 0c 01 4c 8d 60 ff e9 5b fb ff ff 48 c7 c6 d8 97 0c b3 4c 89 e7 48 83 05 0e 7b 3c 0c 01 e8 89 3d 04 00 48 83 05 11 7b 3c 0c 01 <0f> 0b 48 83 05 0f 7b 3c 0c 01 48 83 05 0f 7b 3c 0c 01 48 83 05f >> RSP: 0018:ffffc900015a7bc0 EFLAGS: 00010002 >> RAX: 000000000000003e RBX: ffffffffbace04c8 RCX: 0000000000000002 >> RDX: 0000000000000000 RSI: 0000000000000001 RDI: 00000000ffffffff >> RBP: ffff88817b9acd50 R08: 0000000000000000 R09: c0000000ffefffff >> R10: 0000000000000001 R11: ffffc900015a79b0 R12: ffffea0005e1c900 >> R13: ffffea0005e1de88 R14: 000000000000001f R15: ffff888100071000 >> FS: 0000000000000000(0000) GS:ffff88842fb40000(0000) knlGS:0000000000000000 >> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> CR2: 00007f305e8de3d4 CR3: 000000017bb6f000 CR4: 00000000000006e0 >> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >> Call Trace: >> <TASK> >> free_pages_and_swap_cache+0x64/0x80 >> tlb_flush_mmu+0x6f/0x220 >> unmap_page_range+0xe6c/0x12c0 >> unmap_single_vma+0x90/0x170 >> unmap_vmas+0xc4/0x180 >> exit_mmap+0xde/0x3a0 >> mmput+0xa3/0x250 >> do_exit+0x564/0x1470 >> do_group_exit+0x3b/0x100 >> __do_sys_exit_group+0x13/0x20 >> __x64_sys_exit_group+0x16/0x20 >> do_syscall_64+0x34/0x80 >> entry_SYSCALL_64_after_hwframe+0x44/0xae >> RIP: 0033:0x7f30625401d9 >> Code: Unable to access opcode bytes at RIP 0x7f30625401af. >> RSP: 002b:00007ffe391b0c88 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 >> RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f30625401d9 >> RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000001 >> RBP: 00007f306283d838 R08: 000000000000003c R09: 00000000000000e7 >> R10: fffffffffffffe30 R11: 0000000000000246 R12: 00007f306283d838 >> R13: 00007f3062842e80 R14: 0000000000000000 R15: ffffaa4fb7932430 >> </TASK> >> Modules linked in: >> ---[ end trace e99579b570fe0649 ]--- >> RIP: 0010:release_pages+0x53f/0x840 >> Code: 0c 01 4c 8d 60 ff e9 5b fb ff ff 48 c7 c6 d8 97 0c b3 4c 89 e7 48 83 05 0e 7b 3c 0c 01 e8 89 3d 04 00 48 83 05 11 7b 3c 0c 01 <0f> 0b 48 83 05 0f 7b 3c 0c 01 48 83 05 0f 7b 3c 0c 01 48 83 05f >> RSP: 0018:ffffc900015a7bc0 EFLAGS: 00010002 >> RAX: 000000000000003e RBX: ffffffffbace04c8 RCX: 0000000000000002 >> RDX: 0000000000000000 RSI: 0000000000000001 RDI: 00000000ffffffff >> RBP: ffff88817b9acd50 R08: 0000000000000000 R09: c0000000ffefffff >> R10: 0000000000000001 R11: ffffc900015a79b0 R12: ffffea0005e1c900 >> R13: ffffea0005e1de88 R14: 000000000000001f R15: ffff888100071000 >> FS: 0000000000000000(0000) GS:ffff88842fb40000(0000) knlGS:0000000000000000 >> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> CR2: 00007f305e8de3d4 CR3: 000000017bb6f000 CR4: 00000000000006e0 >> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >> >> Fixes: b94e02822deb ("mm,hwpoison: try to narrow window race for free pages") >> Reported-by: Hulk Robot <hulkci@huawei.com> >> Signed-off-by: Liu Shixin <liushixin2@huawei.com> >> --- >> mm/memory-failure.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/mm/memory-failure.c b/mm/memory-failure.c >> index 68d9a35f8908..160526f83bcb 100644 >> --- a/mm/memory-failure.c >> +++ b/mm/memory-failure.c >> @@ -2288,6 +2288,7 @@ int soft_offline_page(unsigned long pfn, int flags) >> } else if (ret == 0) { >> if (soft_offline_free_page(page) && try_again) { >> try_again = false; >> + flags &= ~MF_COUNT_INCREASED; >> goto retry; >> } >> } >> -- >> 2.25.1 >> > . >
On Wed, Dec 22, 2021 at 09:49:18AM +0800, Liu Shixin wrote: > > > On 2021/12/22 8:37, Naoya Horiguchi wrote: > > On Tue, Dec 21, 2021 at 03:49:08PM +0800, Liu Shixin wrote: > >> Hulk Robot reported a panic in put_page_testzero() when testing madvise() > >> with MADV_SOFT_OFFLINE. The BUG() is triggered when retrying get_any_page(). > >> This is because we keep MF_COUNT_INCREASED flag in second try but the refcnt > >> is not increased. > > Hi Shixin, > > > > Thanks you for the report. > > > > I'm not still sure about the logic behind the bug. > > madvise(MADV_SOFT_OFFLINE) should not work on free pages because > > madvise_inject_error() pins the target page with get_user_pages_fast() > > (MF_COUNT_INCREASED means refcount is incremented by the caller). > > The retry logic can be called when soft_offline_free_page() fails, so > > the logic assumes that the target page is a free page. So why does > > clearing MF_COUNT_INCREASED affect and solve the issue? > > > > It seems to me that if soft_offline_page() is called on a free page > > with MF_COUNT_INCREASED set, then it's problematic itself. > > > > Thanks, > > Naoya Horiguchi > > The page is not free when soft_offline_page() is called. In get_any_page(), > if MF_COUNT_INCREASED is set and !HWPoisonHandlable(page), put_page() > will be called firstly and then goto try_again. The page is freed in this period. Okay, the logic is clear to me now. > >> > >> Fixes: b94e02822deb ("mm,hwpoison: try to narrow window race for free pages") > >> Reported-by: Hulk Robot <hulkci@huawei.com> > >> Signed-off-by: Liu Shixin <liushixin2@huawei.com> Thank you very much. Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com> > >> --- > >> mm/memory-failure.c | 1 + > >> 1 file changed, 1 insertion(+) > >> > >> diff --git a/mm/memory-failure.c b/mm/memory-failure.c > >> index 68d9a35f8908..160526f83bcb 100644 > >> --- a/mm/memory-failure.c > >> +++ b/mm/memory-failure.c > >> @@ -2288,6 +2288,7 @@ int soft_offline_page(unsigned long pfn, int flags) > >> } else if (ret == 0) { > >> if (soft_offline_free_page(page) && try_again) { > >> try_again = false; > >> + flags &= ~MF_COUNT_INCREASED; > >> goto retry; > >> } > >> } > >> -- > >> 2.25.1 > >> > > . > > >
diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 68d9a35f8908..160526f83bcb 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -2288,6 +2288,7 @@ int soft_offline_page(unsigned long pfn, int flags) } else if (ret == 0) { if (soft_offline_free_page(page) && try_again) { try_again = false; + flags &= ~MF_COUNT_INCREASED; goto retry; } }
Hulk Robot reported a panic in put_page_testzero() when testing madvise() with MADV_SOFT_OFFLINE. The BUG() is triggered when retrying get_any_page(). This is because we keep MF_COUNT_INCREASED flag in second try but the refcnt is not increased. page dumped because: VM_BUG_ON_PAGE(page_ref_count(page) == 0) ------------[ cut here ]------------ kernel BUG at include/linux/mm.h:737! invalid opcode: 0000 [#1] PREEMPT SMP CPU: 5 PID: 2135 Comm: sshd Tainted: G B 5.16.0-rc6-dirty #373 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 RIP: 0010:release_pages+0x53f/0x840 Code: 0c 01 4c 8d 60 ff e9 5b fb ff ff 48 c7 c6 d8 97 0c b3 4c 89 e7 48 83 05 0e 7b 3c 0c 01 e8 89 3d 04 00 48 83 05 11 7b 3c 0c 01 <0f> 0b 48 83 05 0f 7b 3c 0c 01 48 83 05 0f 7b 3c 0c 01 48 83 05f RSP: 0018:ffffc900015a7bc0 EFLAGS: 00010002 RAX: 000000000000003e RBX: ffffffffbace04c8 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 00000000ffffffff RBP: ffff88817b9acd50 R08: 0000000000000000 R09: c0000000ffefffff R10: 0000000000000001 R11: ffffc900015a79b0 R12: ffffea0005e1c900 R13: ffffea0005e1de88 R14: 000000000000001f R15: ffff888100071000 FS: 0000000000000000(0000) GS:ffff88842fb40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f305e8de3d4 CR3: 000000017bb6f000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> free_pages_and_swap_cache+0x64/0x80 tlb_flush_mmu+0x6f/0x220 unmap_page_range+0xe6c/0x12c0 unmap_single_vma+0x90/0x170 unmap_vmas+0xc4/0x180 exit_mmap+0xde/0x3a0 mmput+0xa3/0x250 do_exit+0x564/0x1470 do_group_exit+0x3b/0x100 __do_sys_exit_group+0x13/0x20 __x64_sys_exit_group+0x16/0x20 do_syscall_64+0x34/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f30625401d9 Code: Unable to access opcode bytes at RIP 0x7f30625401af. RSP: 002b:00007ffe391b0c88 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f30625401d9 RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 00007f306283d838 R08: 000000000000003c R09: 00000000000000e7 R10: fffffffffffffe30 R11: 0000000000000246 R12: 00007f306283d838 R13: 00007f3062842e80 R14: 0000000000000000 R15: ffffaa4fb7932430 </TASK> Modules linked in: ---[ end trace e99579b570fe0649 ]--- RIP: 0010:release_pages+0x53f/0x840 Code: 0c 01 4c 8d 60 ff e9 5b fb ff ff 48 c7 c6 d8 97 0c b3 4c 89 e7 48 83 05 0e 7b 3c 0c 01 e8 89 3d 04 00 48 83 05 11 7b 3c 0c 01 <0f> 0b 48 83 05 0f 7b 3c 0c 01 48 83 05 0f 7b 3c 0c 01 48 83 05f RSP: 0018:ffffc900015a7bc0 EFLAGS: 00010002 RAX: 000000000000003e RBX: ffffffffbace04c8 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 00000000ffffffff RBP: ffff88817b9acd50 R08: 0000000000000000 R09: c0000000ffefffff R10: 0000000000000001 R11: ffffc900015a79b0 R12: ffffea0005e1c900 R13: ffffea0005e1de88 R14: 000000000000001f R15: ffff888100071000 FS: 0000000000000000(0000) GS:ffff88842fb40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f305e8de3d4 CR3: 000000017bb6f000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Fixes: b94e02822deb ("mm,hwpoison: try to narrow window race for free pages") Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Liu Shixin <liushixin2@huawei.com> --- mm/memory-failure.c | 1 + 1 file changed, 1 insertion(+)