Re: [PATCH v5] tty: sysrq: clear the old reset sequence when reset_seq changes

[sashiko-bot@kernel.org]

> From: Zhan Xusheng <zhanxusheng@xiaomi.com>
> 
> Changing reset_seq at runtime does not work on a keyboard that already
> used the old value, because each keyboard adds the new keys to its own
> copy instead of replacing it:
> 
>   echo 56,29,111 > /sys/module/sysrq/parameters/reset_seq # Alt+Ctrl+Del
>   (press any key)
>   echo 59,60 > /sys/module/sysrq/parameters/reset_seq     # F1+F2
> 
> F1+F2 then does nothing; only all five keys together reset.
> 
> Clear the old keys when the copy is rebuilt.  If sysrq_downtime_ms is
> set, also stop a reset the old keys already started, since releasing
> them no longer cancels it.
> 
> A key pressed while reset_seq is being written can see a partial
> sequence.  With this change that can happen on any keyboard, not only
> on ones that never used a sequence, but the window is a few
> microseconds and not worth closing.
> 
> Fixes: 154b7a489a5b ("Input: sysrq - allow specifying alternate reset sequence")
> Cc: stable@vger.kernel.org
> Assisted-by: Kiro:claude-opus-5.5
> Signed-off-by: Zhan Xusheng <zhanxusheng@xiaomi.com>

Sashiko has reviewed this patch and found no issues.

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