On 18/07/2021 22:22, Matthew Wilcox wrote:

On Sun, Jul 18, 2021 at 11:03:51PM +0200, Oleksandr Natalenko wrote:

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+ stable@vger.kernel.org

On neděle 18. července 2021 23:01:24 CEST Oleksandr Natalenko wrote:

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Hello.

On sobota 17. července 2021 22:22:08 CEST Chris Clayton wrote:

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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 ??:?

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[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.