Re: [PATCH] mm/memory-failure: fix VM_BUG_ON_PAGE(PagePoisoned(page)) when unpoison memory

[Andrew Morton]

On Fri, 12 Jul 2024 14:42:49 +0800 Miaohe Lin <linmiaohe@xxxxxxxxxx> wrote:

> When I did memory failure tests recently, 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.

I'm not seeing the call path.  Is this BUG happening via

static __always_inline void __ClearPage##uname(struct page *page)	\
{									\
	VM_BUG_ON_PAGE(!Page##uname(page), page);			\
	page->page_type |= PG_##lname;					\
}

?

If so, where's the callsite?

> 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
> 

I guess cc:stable.  It looks old?  Can you help to identify the Fixes:
target?

Thanks.