* [PATCH v4] mm/memory-failure: fix VM_BUG_ON_PAGE(PagePoisoned(page)) when unpoison memory
@ 2025-08-28 2:46 Miaohe Lin
2025-08-28 8:59 ` David Hildenbrand
0 siblings, 1 reply; 2+ messages in thread
From: Miaohe Lin @ 2025-08-28 2:46 UTC (permalink / raw)
To: akpm; +Cc: david, nao.horiguchi, linmiaohe, linux-mm, linux-kernel
When I did memory failure tests, below panic occurs:
page dumped because: VM_BUG_ON_PAGE(PagePoisoned(page))
kernel BUG at include/linux/page-flags.h:616!
Oops: invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
CPU: 3 PID: 720 Comm: bash Not tainted 6.10.0-rc1-00195-g148743902568 #40
RIP: 0010:unpoison_memory+0x2f3/0x590
RSP: 0018:ffffa57fc8787d60 EFLAGS: 00000246
RAX: 0000000000000037 RBX: 0000000000000009 RCX: ffff9be25fcdc9c8
RDX: 0000000000000000 RSI: 0000000000000027 RDI: ffff9be25fcdc9c0
RBP: 0000000000300000 R08: ffffffffb4956f88 R09: 0000000000009ffb
R10: 0000000000000284 R11: ffffffffb4926fa0 R12: ffffe6b00c000000
R13: ffff9bdb453dfd00 R14: 0000000000000000 R15: fffffffffffffffe
FS: 00007f08f04e4740(0000) GS:ffff9be25fcc0000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000564787a30410 CR3: 000000010d4e2000 CR4: 00000000000006f0
Call Trace:
<TASK>
unpoison_memory+0x2f3/0x590
simple_attr_write_xsigned.constprop.0.isra.0+0xb3/0x110
debugfs_attr_write+0x42/0x60
full_proxy_write+0x5b/0x80
vfs_write+0xd5/0x540
ksys_write+0x64/0xe0
do_syscall_64+0xb9/0x1d0
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f08f0314887
RSP: 002b:00007ffece710078 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000009 RCX: 00007f08f0314887
RDX: 0000000000000009 RSI: 0000564787a30410 RDI: 0000000000000001
RBP: 0000564787a30410 R08: 000000000000fefe R09: 000000007fffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000009
R13: 00007f08f041b780 R14: 00007f08f0417600 R15: 00007f08f0416a00
</TASK>
Modules linked in: hwpoison_inject
---[ end trace 0000000000000000 ]---
RIP: 0010:unpoison_memory+0x2f3/0x590
RSP: 0018:ffffa57fc8787d60 EFLAGS: 00000246
RAX: 0000000000000037 RBX: 0000000000000009 RCX: ffff9be25fcdc9c8
RDX: 0000000000000000 RSI: 0000000000000027 RDI: ffff9be25fcdc9c0
RBP: 0000000000300000 R08: ffffffffb4956f88 R09: 0000000000009ffb
R10: 0000000000000284 R11: ffffffffb4926fa0 R12: ffffe6b00c000000
R13: ffff9bdb453dfd00 R14: 0000000000000000 R15: fffffffffffffffe
FS: 00007f08f04e4740(0000) GS:ffff9be25fcc0000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000564787a30410 CR3: 000000010d4e2000 CR4: 00000000000006f0
Kernel panic - not syncing: Fatal exception
Kernel Offset: 0x31c00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
---[ end Kernel panic - not syncing: Fatal exception ]---
The root cause is that unpoison_memory() tries to check the PG_HWPoison
flags of an uninitialized page. So VM_BUG_ON_PAGE(PagePoisoned(page)) is
triggered. This can be reproduced by below steps:
1.Offline memory block:
echo offline > /sys/devices/system/memory/memory12/state
2.Get offlined memory pfn:
page-types -b n -rlN
3.Write pfn to unpoison-pfn
echo <pfn> > /sys/kernel/debug/hwpoison/unpoison-pfn
This scene can be identified by pfn_to_online_page() returning NULL.
And ZONE_DEVICE pages are never expected, so we can simply fail if
pfn_to_online_page() == NULL to fix the bug.
Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online")
Suggested-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
---
v2:
Use pfn_to_online_page per David. Thanks.
v3:
Simply fail if pfn_to_online_page() == NULL per David. Thanks.
v4:
Add Fixes tag and remove pfn_valid check per David. Thanks.
---
mm/memory-failure.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index c15ffee7d32b..4af8875b07b6 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -2569,10 +2569,9 @@ int unpoison_memory(unsigned long pfn)
static DEFINE_RATELIMIT_STATE(unpoison_rs, DEFAULT_RATELIMIT_INTERVAL,
DEFAULT_RATELIMIT_BURST);
- if (!pfn_valid(pfn))
- return -ENXIO;
-
- p = pfn_to_page(pfn);
+ p = pfn_to_online_page(pfn);
+ if (!p)
+ return -EIO;
folio = page_folio(p);
mutex_lock(&mf_mutex);
--
2.33.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v4] mm/memory-failure: fix VM_BUG_ON_PAGE(PagePoisoned(page)) when unpoison memory
2025-08-28 2:46 [PATCH v4] mm/memory-failure: fix VM_BUG_ON_PAGE(PagePoisoned(page)) when unpoison memory Miaohe Lin
@ 2025-08-28 8:59 ` David Hildenbrand
0 siblings, 0 replies; 2+ messages in thread
From: David Hildenbrand @ 2025-08-28 8:59 UTC (permalink / raw)
To: Miaohe Lin, akpm; +Cc: nao.horiguchi, linux-mm, linux-kernel
On 28.08.25 04:46, Miaohe Lin wrote:
> When I did memory failure tests, below panic occurs:
>
> page dumped because: VM_BUG_ON_PAGE(PagePoisoned(page))
> kernel BUG at include/linux/page-flags.h:616!
> Oops: invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
> CPU: 3 PID: 720 Comm: bash Not tainted 6.10.0-rc1-00195-g148743902568 #40
> RIP: 0010:unpoison_memory+0x2f3/0x590
> RSP: 0018:ffffa57fc8787d60 EFLAGS: 00000246
> RAX: 0000000000000037 RBX: 0000000000000009 RCX: ffff9be25fcdc9c8
> RDX: 0000000000000000 RSI: 0000000000000027 RDI: ffff9be25fcdc9c0
> RBP: 0000000000300000 R08: ffffffffb4956f88 R09: 0000000000009ffb
> R10: 0000000000000284 R11: ffffffffb4926fa0 R12: ffffe6b00c000000
> R13: ffff9bdb453dfd00 R14: 0000000000000000 R15: fffffffffffffffe
> FS: 00007f08f04e4740(0000) GS:ffff9be25fcc0000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000564787a30410 CR3: 000000010d4e2000 CR4: 00000000000006f0
> Call Trace:
> <TASK>
> unpoison_memory+0x2f3/0x590
> simple_attr_write_xsigned.constprop.0.isra.0+0xb3/0x110
> debugfs_attr_write+0x42/0x60
> full_proxy_write+0x5b/0x80
> vfs_write+0xd5/0x540
> ksys_write+0x64/0xe0
> do_syscall_64+0xb9/0x1d0
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7f08f0314887
> RSP: 002b:00007ffece710078 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
> RAX: ffffffffffffffda RBX: 0000000000000009 RCX: 00007f08f0314887
> RDX: 0000000000000009 RSI: 0000564787a30410 RDI: 0000000000000001
> RBP: 0000564787a30410 R08: 000000000000fefe R09: 000000007fffffff
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000009
> R13: 00007f08f041b780 R14: 00007f08f0417600 R15: 00007f08f0416a00
> </TASK>
> Modules linked in: hwpoison_inject
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:unpoison_memory+0x2f3/0x590
> RSP: 0018:ffffa57fc8787d60 EFLAGS: 00000246
> RAX: 0000000000000037 RBX: 0000000000000009 RCX: ffff9be25fcdc9c8
> RDX: 0000000000000000 RSI: 0000000000000027 RDI: ffff9be25fcdc9c0
> RBP: 0000000000300000 R08: ffffffffb4956f88 R09: 0000000000009ffb
> R10: 0000000000000284 R11: ffffffffb4926fa0 R12: ffffe6b00c000000
> R13: ffff9bdb453dfd00 R14: 0000000000000000 R15: fffffffffffffffe
> FS: 00007f08f04e4740(0000) GS:ffff9be25fcc0000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000564787a30410 CR3: 000000010d4e2000 CR4: 00000000000006f0
> Kernel panic - not syncing: Fatal exception
> Kernel Offset: 0x31c00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
> ---[ end Kernel panic - not syncing: Fatal exception ]---
>
> The root cause is that unpoison_memory() tries to check the PG_HWPoison
> flags of an uninitialized page. So VM_BUG_ON_PAGE(PagePoisoned(page)) is
> triggered. This can be reproduced by below steps:
> 1.Offline memory block:
> echo offline > /sys/devices/system/memory/memory12/state
> 2.Get offlined memory pfn:
> page-types -b n -rlN
> 3.Write pfn to unpoison-pfn
> echo <pfn> > /sys/kernel/debug/hwpoison/unpoison-pfn
>
> This scene can be identified by pfn_to_online_page() returning NULL.
> And ZONE_DEVICE pages are never expected, so we can simply fail if
> pfn_to_online_page() == NULL to fix the bug.
>
> Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online")
> Suggested-by: David Hildenbrand <david@redhat.com>
> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
> ---
Acked-by: David Hildenbrand <david@redhat.com>
--
Cheers
David / dhildenb
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2025-08-28 2:46 [PATCH v4] mm/memory-failure: fix VM_BUG_ON_PAGE(PagePoisoned(page)) when unpoison memory Miaohe Lin
2025-08-28 8:59 ` David Hildenbrand
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