Messages in this thread | | | From | Lai Jiangshan <> | Date | Mon, 1 Aug 2022 11:56:50 +0800 | Subject | Re: [PATCH] workqueue: Use active mask for new worker when pool is DISASSOCIATED |
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On Sat, Jul 30, 2022 at 12:19 PM Schspa Shi <schspa@gmail.com> wrote: > > > Peter Zijlstra <peterz@infradead.org> writes: > > > On Wed, Jul 13, 2022 at 05:52:58PM +0800, Lai Jiangshan wrote: > >> > >> > >> CC Peter. > >> Peter has changed the CPU binding code in workqueue.c. > > > > [ 1622.829091] WARNING: CPU: 3 PID: 31 at kernel/sched/core.c:7756 sched_cpu_dying+0x74/0x204 > > [ 1622.829374] CPU: 3 PID: 31 Comm: migration/3 Tainted: P O 5.10.59-rt52 #2 > > ^^^^^^^^^^^^^^^^^^^^^ > > > > I think we can ignore this as being some ancient kernel. Please try > > something recent. > > Hi peter: > > I spent a few days writing a test case and reproduced the problem on > kernel 5.19. I think it's time for us to review the V3 patch for a fix. > > The V3 patch is at > https://lore.kernel.org/all/20220714031645.28004-1-schspa@gmail.com/ > Please help to review it.
Because of the implementation of is_cpu_allowed(), I am still suspicious about how the newly created worker can be woken up in the dying cpu since it has no KTHREAD_IS_PER_CPU set.
Is it a dying cpu when onlining a CPU fails? I think balance_push is not set in this case when it fails at some point during online. But I haven't looked into the details and linked the clues.
> > Test branch as: > https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git/tag/?h=v5.19-rc8-rt8 >
Can it only be triggered in the rt kernel?
> I think this code is new enough to demonstrate that the problem persists. > > The log as fellowing: > > [ 3103.198684] ------------[ cut here ]------------ > [ 3103.198684] Dying CPU not properly vacated! > [ 3103.198684] WARNING: CPU: 1 PID: 23 at kernel/sched/core.c:9575 sched_cpu_dying.cold+0xc/0xc3 > [ 3103.198684] Modules linked in: work_test(O)
Could you give me the code of this module?
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