Re: [RFC PATCH 14/16] irq: Add support for core-wide protection of IRQ and softirq

[Thomas Gleixner]

"Li, Aubrey" <aubrey.li@xxxxxxxxxxxxxxx> writes:
> On 2020/7/1 5:32, Vineeth Remanan Pillai wrote:
>
> We saw a lot of soft lockups on the screen when we tested v6.
>
> [  186.527883] watchdog: BUG: soft lockup - CPU#86 stuck for 22s! [uperf:5551]
> [  186.535884] watchdog: BUG: soft lockup - CPU#87 stuck for 22s! [uperf:5444]
> [  186.555883] watchdog: BUG: soft lockup - CPU#89 stuck for 22s! [uperf:5547]
> [  187.547884] rcu: INFO: rcu_sched self-detected stall on CPU
> [  187.553760] rcu: 	40-....: (14997 ticks this GP) idle=49a/1/0x4000000000000002 softirq=1711/1711 fqs=7279 
> [  187.564685] NMI watchdog: Watchdog detected hard LOCKUP on cpu 14
> [  187.564723] NMI watchdog: Watchdog detected hard LOCKUP on cpu 38
>
> The problem is gone when we reverted this patch. We are running multiple
> uperf threads(equal to cpu number) in a cgroup with coresched enabled.
> This is 100% reproducible on our side.

ROTFL. I just predicted that from staring at the patch ....