Hi Visa, On Sun, Jun 24, 2018 at 05:54:15PM +0000, Visa Hankala wrote: > On Sun, Jun 24, 2018 at 12:37:45PM +0200, Walter Alejandro Iglesias wrote: > > panic: mtx 0xffffffff81c86470: locking against myself > > Stopped at db_enter+0x12: popq %r11 > > TID PID UID PRFLAGS PFLAGS CPU COMMAND > > 104021 96401 1000 0x3 0x4000000 2 mpv > > *402610 50624 1000 0x32 0 0K Xorg > > > > db_enter() at db_enter+0x12 > > panic() at panic+0x138 > > __mtx_enter_try(53b9235709d40154) at __mtx_enter_try+0xb5 > > _mtx_enter(ffffffff81cf3e60,ffffffff81a5d6a2,0) at _mtx_enter+0x5a > > printf(c9ef1007dec621e0) at printf+0x70 > > witness_checkorder(2e4447d1b3cbb9af,ffffffff81c2ac7c,32a,0,ffffffff81da6d00) > > at > > witness_checkorder+0x943 > > ___mp_lock(ffff8000330cd760,d,7) at ___mp_lock+0x70 > > selwakeup(e80faaebded7c1a2) at selwakeup+0x9c > > ptsstart(8ce5939828d5e23) at ptsstart+0x79 > > tputchar(174549bf676e909c,ffff800000afa400) at tputchar+0x85 > > kputchar(75d50501b895e9e4,0,ffffffff81a5d6a2) at kputchar+0x91 > > kprintf() at kprintf+0xe8 > > printf(c9ef1007dec621e0) at printf+0x85 > > witness_checkorder(2e4447d1b3cba2fe,ffffffff81af9df1,298,ffffffff81c8a678,ffffff > > ff81c8a688) at witness_checkorder+0x943 > > end trace frame: 0xffff80003302e978, count: 0 > > If the panic happens again, please run the following commands in ddb(4) > and post the output: > > show locks > show all locks
The true is it happend twice. On the first one fsck(8) couldn't recover my root file system. After rebooting I couldn't even log in (as user or root) and I had to reinstall. That's way I'm not confident about "voluntary" reproducing the bug. :-) But if it happens again take for sure I'll send you the output of those commands (and per cpu traces). > > It is not clear from the stack trace why the system begins to report > a lock order problem in the first place (the first witness_checkorder > and the printf at the end of the stack trace). > > The panic itself is related to the problem of using other kernel > subsystems from WITNESS. I will try to make a fix that should prevent > the panic in most cases. Thanks! Walter