Re: [PATCH] watchdog: Force console verbose when reporting lockups

From: Petr Mladek

Date: Mon Oct 26 2026 - 12:21:07 EST


On Wed 2026-10-07 05:17:26, Tzung-Bi Shih wrote:
> When a hard or soft lockup is detected, the watchdog prints a header at
> KERN_EMERG (<0>), followed by diagnostic details (modules, registers,
> and backtraces) at KERN_WARNING/KERN_DEFAULT (<4>) and KERN_INFO (<6>).
> If console_loglevel is quiet (<= 4), the console skips those <4>/<6>
> diagnostic messages before vpanic() has a chance to call
> console_verbose(). With the buddy detector, this leaves only the
> detector CPU's panic stack on the console and nothing about the locked
> CPU:
>
> <0>[ 1535.991833][ C6] watchdog: Watchdog detected hard LOCKUP on cpu 7
> <0>[ 1535.995960][ C6] Kernel panic - not syncing: Hard LOCKUP
> <4>[ 1535.995970][ C6] CPU: 6 UID: 0 PID: 0 Comm: swapper/6 ...
> <4>[ 1535.995997][ C6] Call trace:
> ...
> <4>[ 1535.996063][ C6] watchdog_hardlockup_check+0x1e0/0x288
> <4>[ 1535.996075][ C6] watchdog_buddy_check_hardlockup+0xb4/0xc0
>
> Similar to commit 168e06f7937d ("kernel/hung_task.c: force console
> verbose before panic"), call console_verbose() before printing the
> lockup report so the diagnostic output is not suppressed.
>
> Signed-off-by: Tzung-Bi Shih <tzungbi@xxxxxxxxxx>

Just for record, this looks good to me:

Reviewed-by: Petr Mladek <pmladek@xxxxxxxx>

Best Regards,
Petr