Hi all,
After some off-list advice from Patrick to enable MP_LOCKDEBUG in
order to debug the hangs I reported [1], I did exactly that and was
running a self-built kernel for some time. This morning, I wanted to
upgrade to the latest snapshot so I also cvs up'd and rebuilt my
kernel with MP_LOCKDEBUG. However, now I get __mp_lock_spin during
boot:
root on sd2a (a0b80508b6693ba1.a) swap on sd2b dump on sd2b
inteldrm0: 1920x1080, 32bpp
wsdisplay0 at inteldrm0 mux 1
__mp_lock_spin: 0xffffffff822d1120 lock spun out
Stopped at db_enter+0x10: popq %rbp
ddb{1}> trace
db_enter() at db_enter+0x10
__mp_lock(ffffffff822d1120) at __mp_lock+0xa2
__mp_acquire_count(ffffffff822d1120,1) at __mp_acquire_count+0x38
mi_switch() at mi_switch+0x299
sleep_finish(ffff8000226d4f80,1) at sleep_finish+0x11c
msleep(ffff80000011d980,ffff80000011d998,20,ffffffff81e828e3,0) at msleep+0xcc
taskq_next_work(ffff80000011d980,ffff8000226d5040) at taskq_next_work+0x61
taskq_thread(ffff80000011d980) at taskq_thread+0x6c
end trace frame: 0x0, count: -8
Everything was fine with (had MP_LOCKDEBUG enabled):
OpenBSD 7.0 (GENERIC.MP) #17: Tue Sep 14 20:07:14 CEST 2021
[email protected]:/usr/src/sys/arch/amd64/compile/GENERIC.MP
And a kernel that's mere hours newer crashes:
OpenBSD 7.0 (GENERIC.MP) #18: Wed Sep 15 09:26:20 CEST 2021
[email protected]:/usr/src/sys/arch/amd64/compile/GENERIC.MP
I enabled verbose booting to see if anything else was happening, but
no:
inteldrm0: 1920x1080, 32bpp
>>> probing for drm*
>>> drm probe returned 0
>>> probing for intagp*
>>> intagp probe returned 0
>>> probing for wsdisplay*
>>> wsdisplay probe returned 1
>>> probing for wsdisplay0
>>> wsdisplay probe returned 10
>>> wsdisplay probe won
wsdisplay0 at inteldrm0 mux 1
__mp_lock_spin: 0xffffffff822d1120 lock spun out
Stopped at db_enter+0x10: popq %rbp
Looking at the recent commits to CVS I see no obvious reason why this
was crashing. Any suggestions for a commit to revert to see if it is
the cause?
Cheers,
Paul
[1]: https://marc.info/?l=openbsd-bugs&m=163155522416560&w=2
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