On 2024-05-23 23:03:52 [+0200], Vlastimil Babka wrote: > I'm puzzled by this. We use local_lock_irqsave() on !PREEMPT_RT everywhere. > IIUC this warning says we did the irqsave() and then found out somebody else > already set the owner? But that means they also did that irqsave() and set > themselves as l->owner. Does that mey there would be a spurious irq enable > that didn't go through local_unlock_irqrestore()? correct. > > Also this particular stack is from the work, which is scheduled by > queue_work_on() in flush_all_cpus_locked(), which also has a > lockdep_assert_cpus_held() so it should fullfill the "the caller must ensure > the cpu doesn't go away" property. But I think even if this ended up on the > wrong cpu (for the full duration or migrated while processing the work item) > somehow, it wouldn't be able to cause such warning, but rather corrupt > something else Based on > >> CPU: 3 PID: 5221 Comm: kworker/3:3 Not tainted 6.9.0-syzkaller-10713-g2a8120d7b482 #0 the code was invoked on CPU3 and the kworker was made for CPU3. This is all fine. All access for the lock in question is within a few lines so there is no unbalance lock/ unlock or IRQ-unlock which could explain it. Sebastian
