Re: linux-5.13.2: warning from kernel/rcu/tree_plugin.h:359

[Chris Clayton]

On 18/07/2021 22:22, Matthew Wilcox wrote:
> On Sun, Jul 18, 2021 at 11:03:51PM +0200, Oleksandr Natalenko wrote:
>> + stable@xxxxxxxxxxxxxxx
>>
>> On neděle 18. července 2021 23:01:24 CEST Oleksandr Natalenko wrote:
>>> Hello.
>>>
>>> On sobota 17. července 2021 22:22:08 CEST Chris Clayton wrote:
>>>> I checked the output from dmesg yesterday and found the following warning:
>>>>
>>>> [Fri Jul 16 09:15:29 2021] ------------[ cut here ]------------
>>>> [Fri Jul 16 09:15:29 2021] WARNING: CPU: 11 PID: 2701 at
>>>> kernel/rcu/tree_plugin.h:359 rcu_note_context_switch+0x37/0x3d0 [Fri Jul
> 
> Could you run ./scripts/faddr2line vmlinux rcu_note_context_switch+0x37/0x3d0
> 
$ ./scripts/faddr2line vmlinux rcu_note_context_switch+0x37/0x3d0
rcu_note_context_switch+0x37/0x3d0:
rcu_note_context_switch at ??:?

>>>> [Fri Jul 16 09:15:29 2021] Call Trace:
>>>> [Fri Jul 16 09:15:29 2021]  __schedule+0x86/0x810
>>>> [Fri Jul 16 09:15:29 2021]  schedule+0x40/0xe0
>>>> [Fri Jul 16 09:15:29 2021]  io_schedule+0x3d/0x60
>>>> [Fri Jul 16 09:15:29 2021]  wait_on_page_bit_common+0x129/0x390
>>>> [Fri Jul 16 09:15:29 2021]  ? __filemap_set_wb_err+0x10/0x10
>>>> [Fri Jul 16 09:15:29 2021]  __lock_page_or_retry+0x13f/0x1d0
>>>> [Fri Jul 16 09:15:29 2021]  do_swap_page+0x335/0x5b0
>>>> [Fri Jul 16 09:15:29 2021]  __handle_mm_fault+0x444/0xb20
>>>> [Fri Jul 16 09:15:29 2021]  handle_mm_fault+0x5c/0x170
> 
> You were handling a page fault at the time.  The page you wanted was
> on swap and this warning fired as a result of waiting for the page
> to come back in from swap.  There are a number of warnings in that
> function, so it'd be good to track down exactly which one it is.
>