Re: [workqueue] d5bff968ea: WARNING:at_kernel/workqueue.c:#process_one_work

[Xing Zhengjun]

On 1/29/2021 2:08 AM, Paul E. McKenney wrote:
> On Thu, Jan 28, 2021 at 05:09:05PM +0800, Hillf Danton wrote:
> > On Thu, 28 Jan 2021 15:52:40 +0800 Xing Zhengjun wrote:
>
> [ . . . ]
>
> > > I test the patch 4 times, no warning appears in the kernel log.
> >
> > Thank you so much Zhengjun!
> >
> > And the overall brain dump so far is
> >
> > 1/ before and after d5bff968ea, changing the allowed ptr at online time
> > is the key to quiesce the warning in process_one_work().
> >
> > 2/ marking pcpu before changing aptr in rebind_workers() is mandatory in
> > regards to cutting the risk of triggering such a warning.
> >
> > 3/ we canot maintain such an order without quiescing the 508 warning for
> > kworkers. And we have a couple of excuses to do so, a) the number of
> > allowed CPUs is no longer checked in is_per_cpu_kthread() instead of
> > PF_NO_SETAFFINITY, b) there is always a followup act to change the aptr
> > in order to fix the number of aCPUs.
> >
> > 4/ same order is maintained also at rescue time.
>
> Just out of curiosity, does this test still fail on current mainline?
>
> 							Thanx, Paul
I test mainline v5.11-rc5, it has no issue. The issue is only for 
d5bff968ea which is in 
https://git.kernel.org/cgit/linux/kernel/git/paulmck/linux-rcu.git 
dev.2021.01.11b.

--
Zhengjun Xing