Re: [syzbot] [serial?] WARNING in register_console

[Tetsuo Handa]

On 2026/08/07 15:45, Jiri Slaby wrote:
>> printk: legacy console [ttyS0] enabled
>> ------------[ cut here ]------------
>> IS_ERR(kt)
> 
> Well, the creation of "pr/legacy" thread failed. Would be nice to see what is actual PTR_ERR(kt).
> 
>> RAX: fffffffffffffffc

fffffffffffffffc = -EINTR

> console_store() is serialized by a mutex. So this should not be a race. I cannot reproduce using:
> while :; do
>   echo 0 >/sys/class/tty/ttyS0/console
>   echo 1 > /sys/class/tty/ttyS0/console
> done
> 
> That's what the reproducer suggests is the cause.

A patch was already posted to
https://lkml.kernel.org/r/76bb4c1c-5d85-4635-b3bb-fc06f292c59e@xxxxxxxxxxxxxxxxxxx
and sashiko's review is available at
https://sashiko.dev/#/patchset/76bb4c1c-5d85-4635-b3bb-fc06f292c59e@xxxxxxxxxxxxxxxxxxx .