Re: ww_mutex.sh hangs since v5.16-rc1

[Peter Zijlstra]

On Wed, Dec 01, 2021 at 09:26:18AM +0800, Li Zhijian wrote:
> Hi Folks
> 
> 
> LKP/0Day found that ww_mutex.sh cannot complete since v5.16-rc1, but
> I'm pretty sorry that we failed to bisect the FBC, instead, the bisection pointed
> to a/below merge commit(91e1c99e17) finally.
> 
> Due to this hang, other tests in the same group are also blocked in 0Day, we
> hope we can fix this hang ASAP.
> 
> So if you have any idea about this, or need more debug information, feel free to let me know :)
> 
> BTW, ww_mutex.sh was failed in v5.15 without hang, and looks it cannot reproduce on a vm.

On real hardware:

root@ivb-ep:/usr/src/linux-2.6/tools/testing/selftests/locking# uname -a
Linux ivb-ep 5.16.0-rc3-00284-g68601c558556 #1 SMP PREEMPT Thu Dec 2 23:03:29 CET 2021 x86_64 GNU/Linux
root@ivb-ep:/usr/src/linux-2.6/tools/testing/selftests/locking# ./ww_mutex.sh
locking/ww_mutex: ok

[ 1907.907801] Beginning ww mutex selftests
[ 1915.700077] All ww mutex selftests passed


What else do I try?