Re: [PATCH] PM / Suspend: Avoid soft lockup warning with suspend_test

From: Florian Fainelli
Date: Thu Sep 23 2021 - 15:29:35 EST


On 9/23/21 11:51 AM, Florian Fainelli wrote:
> When testing with a large (>= 22 seconds) pm_test_delay we can see the
> NMI soft lockup barfing at us because a task has been blocked for too
> long. This can be reproduced with:
>
> echo devices > /sys/power/pm_test
> echo 30 > /sys/module/suspend/parameters/pm_test_delay
>
> Unroll the loop and touch the NMI watchdog every 1s to avoid the lockup
> warnings.
>
> Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx>

Looks like I cannot reproduce the NMI soft lockup warnings with 5.10 and
newer, however I can easily trigger RCU stalls. Let me sleep on it for a
bit and see what needs fixing in 5.15 and newer. Any feedback welcome.
--
Florian