Messages in this thread | | | Date | Tue, 29 Jan 2019 10:45:44 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: WARN_ON_ONCE(!new_owner) within wake_futex_pi() triggered |
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On Tue, 29 Jan 2019, Heiko Carstens wrote: > On Mon, Jan 28, 2019 at 04:53:19PM +0100, Thomas Gleixner wrote: > > Patch below cures that. > > With your patch the kernel warning doesn't occur anymore. So if this > is supposed to be the fix feel free to add:
Yes, it's supposed to be the fix. > > However now I see every now and then the following failure from the > same test case: > > tst-robustpi8: ../nptl/pthread_mutex_lock.c:425: __pthread_mutex_lock_full: Assertion `INTERNAL_SYSCALL_ERRNO (e, __err) != ESRCH || !robust' failed. > > /* ESRCH can happen only for non-robust PI mutexes where > the owner of the lock died. */ > assert (INTERNAL_SYSCALL_ERRNO (e, __err) != ESRCH || !robust); > > I just verified that this happened also without your patch, I just > didn't see it since I started my tests with panic_on_warn=1 and the > warning triggered always earlier. > So, this seems to be something different.
Moo. I ran the test loop all night (simply because I forgot to stop it) and of course this does not trigger here. Could you try to gather a bit more information with lightweight tracing?
Something like the below should give us at least a clue. Stop the tst loop when the assert triggers and then extract the trace.
Thanks,
tglx
8<--------------
#!/bin/sh
# Substitute with your ld comm string if it starts differently C=ld-linux
echo 'comm ~ "$C*"' >/sys/kernel/debug/tracing/events/syscalls/sys_enter_futex/filter echo 'comm ~ "$C*"' >/sys/kernel/debug/tracing/events/syscalls/sys_exit_futex/filter echo 'comm ~ "$C*"' >/sys/kernel/debug/tracing/events/sched/sched_process_exit/filter echo 'prev_comm ~ "$C*" || next_comm ~ "$C*"' >/sys/kernel/debug/tracing/events/sched/sched_switch/filter
echo 1 > /sys/kernel/debug/tracing/events/syscalls/sys_enter_futex/enable echo 1 > /sys/kernel/debug/tracing/events/syscalls/sys_exit_futex/enable echo 1 > /sys/kernel/debug/tracing/events/sched/sched_process_exit/enable echo 1 > /sys/kernel/debug/tracing/events/sched/sched_switch/enable
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