Re: [PATCH 5.10-rt] printk: fix suppressed message print when reboot/panic

From: John Ogness
Date: Mon Mar 21 2022 - 05:31:01 EST


On 2022-03-21, Schspa Shi <schspa@xxxxxxxxx> wrote:
> Update printk_seq for suppressed message.
>
> Affects 5.9-rt and 5.10-rt
>
> When message is suppressed, printk_seq should be updated, otherwise
> this message will be printed when reboot. This problem was introduced
> in commit 3edc0c85d154 ("printk: Rebase on top of new ring buffer").
>
> Signed-off-by: Schspa Shi <schspa@xxxxxxxxx>

Reviewed-by: John Ogness <john.ogness@xxxxxxxxxxxxx>

Nice catch. Thanks.

5.15-rt also has this issue, although the fix is slightly different. For
5.15-rt, writing to con->printk_seq (via latched_seq_write()) requires
the console locked. Would you like to post a patch for 5.15-rt as well,
or would you like me to do it?

5.16 and beyond does not have this issue.

John Ogness