On Wed, Dec 11, 2024 at 12:57:26PM -1000, Tejun Heo wrote: > Hello, Dave. > > Sorry about the really late reply. > > On Fri, Nov 22, 2024 at 11:38:19AM +1100, Dave Chinner wrote: > > Hi Tejun, > > > > I just upgraded my test VMs from 6.12.0 to a current TOT kernel and > > I got several of these warnings whilst running fstests whilst > > running CPU hotplug online/offline concurrently with various tests: > > > > [ 2508.109594] ------------[ cut here ]------------ > > [ 2508.115669] WARNING: CPU: 23 PID: 133 at kernel/kthread.c:76 kthread_set_per_cpu+0x33/0x50 > ... > > [ 2508.253909] <TASK> > > [ 2508.311972] unbind_worker+0x1b/0x70 > > [ 2508.315444] workqueue_offline_cpu+0xd8/0x1f0 > > [ 2508.319554] cpuhp_invoke_callback+0x13e/0x4f0 > > [ 2508.328936] cpuhp_thread_fun+0xda/0x120 > > [ 2508.332746] smpboot_thread_fn+0x132/0x1d0 > > [ 2508.336645] kthread+0x147/0x170 > > [ 2508.347646] ret_from_fork+0x3e/0x50 > > [ 2508.353845] ret_from_fork_asm+0x1a/0x30 > > [ 2508.357773] </TASK> > > [ 2508.357776] ---[ end trace 0000000000000000 ]--- > > So, this is kthread saying that the thread passed to it doesn't have > PF_KTHREAD set. There hasn't been any related changes and the flag is never > cleared once set, so I don't see how that could be for a kworker. .... > > I didn't see these on 6.12.0, so I'm guessing that there is > > something in the merge window that has started triggering this. > > I tried a few mixtures of stress-ng + continuous hot [un]plugging but can't > reproduce in the current linus#master. Do you still see this happening? I don't know. The machine that I was using to reproduce this has been down with hardware failure for the last two weeks. I might have it back up today, and then I'll be able to start exercising this again. -Dave. -- Dave Chinner david@xxxxxxxxxxxxx
