Re: Patched gpsd and /dev/pps0 results in "sleeping thread" kernel panic
Date: Wed, 01 Sep 2021 03:25:08 UTC
On Tue, Aug 31, 2021 at 9:13 PM Ian Lepore <ian@freebsd.org> wrote: > On Tue, 2021-08-31 at 21:07 -0600, Warner Losh wrote: > > On Tue, Aug 31, 2021 at 8:11 PM Craig Leres <leres@freebsd.org> > > wrote: > > > > > > > > On 8/31/21 6:54 PM, Warner Losh wrote: > > > > Can you post a traceback? We recently tightened up the sleeping > > > conditions > > > > and many of the panics are straight forward to fix > > > > > > Is this sufficient? > > > > > > > Maybe. I'm guessing that the pps driver isn't setting driver_mtx for > > the > > pps_state that it keeps, so when we're sleeping in pps_ioctl we're > > not > > dropping the the ppbus lock, which leads to this diagnostic. > > > > Warner > > > > > > > Exactly so, I've just been digging through the code. It's not an easy > fix because the ppbus pps driver doesn't have access to the ppbus mutex > at the point where it's registering to be a pps driver. > I just came to the conclusion that either we'd need to create a call in ppbus to set this mutex, or to return its lock... > Craig, is there any chance you can configure your hardware so that the > PPS signal is connected to either the CTS or DCD pin of a uart (even > the same uart that's communicating with the gps receiver should work if > you use DCD)? You'll get jitter and accuracy performance comparable to > the parallel port pin, and avoid this mutex/sleeping problem. > That's easier, but depending on the hardware might be harder :( Warner > -- Ian > > > > > > Craig > > > > > > toc2 4 # kgdb /boot/kernel/kernel /var/crash/vmcore.1 > > > GNU gdb (GDB) 10.2 [GDB v10.2 for FreeBSD] > > > Copyright (C) 2021 Free Software Foundation, Inc. > > > License GPLv3+: GNU GPL version 3 or later > > > <http://gnu.org/licenses/gpl.html> > > > This is free software: you are free to change and redistribute it. > > > There is NO WARRANTY, to the extent permitted by law. > > > Type "show copying" and "show warranty" for details. > > > This GDB was configured as "x86_64-portbld-freebsd12.2". > > > Type "show configuration" for configuration details. > > > For bug reporting instructions, please see: > > > <https://www.gnu.org/software/gdb/bugs/>. > > > Find the GDB manual and other documentation resources online at: > > > <http://www.gnu.org/software/gdb/documentation/>. > > > > > > For help, type "help". > > > Type "apropos word" to search for commands related to "word"... > > > Reading symbols from /boot/kernel/kernel... > > > Reading symbols from /boot/kernel.LBLNET/kernel.debug... > > > > > > Unread portion of the kernel message buffer: > > > Sleeping thread (tid 101408, pid 2046) owns a non-sleepable lock > > > KDB: stack backtrace of thread 101408: > > > sched_switch() at sched_switch+0x630/frame 0xfffffe0070e4f760 > > > mi_switch() at mi_switch+0xd4/frame 0xfffffe0070e4f790 > > > sleepq_catch_signals() at sleepq_catch_signals+0x403/frame > > > 0xfffffe0070e4f7e0 > > > sleepq_timedwait_sig() at sleepq_timedwait_sig+0x14/frame > > > 0xfffffe0070e4f820 > > > _sleep() at _sleep+0x1b3/frame 0xfffffe0070e4f8a0 > > > pps_ioctl() at pps_ioctl+0x298/frame 0xfffffe0070e4f8f0 > > > ppsioctl() at ppsioctl+0x48/frame 0xfffffe0070e4f920 > > > devfs_ioctl() at devfs_ioctl+0xb0/frame 0xfffffe0070e4f970 > > > VOP_IOCTL_APV() at VOP_IOCTL_APV+0x7b/frame 0xfffffe0070e4f9a0 > > > vn_ioctl() at vn_ioctl+0x16a/frame 0xfffffe0070e4fab0 > > > devfs_ioctl_f() at devfs_ioctl_f+0x1e/frame 0xfffffe0070e4fad0 > > > kern_ioctl() at kern_ioctl+0x2b7/frame 0xfffffe0070e4fb30 > > > sys_ioctl() at sys_ioctl+0xfa/frame 0xfffffe0070e4fc00 > > > amd64_syscall() at amd64_syscall+0x387/frame 0xfffffe0070e4fd30 > > > fast_syscall_common() at fast_syscall_common+0xf8/frame > > > 0xfffffe0070e4fd30 > > > --- syscall (54, FreeBSD ELF64, sys_ioctl), rip = 0x8004c899a, rsp > > > = > > > 0x7fffdfdfc6a8, rbp = 0x7fffdfdfc730 --- > > > panic: sleeping thread > > > cpuid = 8 > > > time = 1630456142 > > > KDB: stack backtrace: > > > db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame > > > 0xfffffe005ab73ab0 > > > vpanic() at vpanic+0x17b/frame 0xfffffe005ab73b00 > > > panic() at panic+0x43/frame 0xfffffe005ab73b60 > > > propagate_priority() at propagate_priority+0x282/frame > > > 0xfffffe005ab73b90 > > > turnstile_wait() at turnstile_wait+0x30c/frame 0xfffffe005ab73be0 > > > __mtx_lock_sleep() at __mtx_lock_sleep+0x199/frame > > > 0xfffffe005ab73c70 > > > ppcintr() at ppcintr+0x2a0/frame 0xfffffe005ab73c90 > > > ithread_loop() at ithread_loop+0x23c/frame 0xfffffe005ab73cf0 > > > fork_exit() at fork_exit+0x7e/frame 0xfffffe005ab73d30 > > > fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe005ab73d30 > > > --- trap 0, rip = 0, rsp = 0, rbp = 0 --- > > > Uptime: 17m20s > > > Dumping 607 out of 12240 > > > MB:..3%..11%..22%..32%..43%..51%..61%..72%..82%..93% > > > > > > __curthread () at /usr/src/sys/amd64/include/pcpu_aux.h:55 > > > 55 /usr/src/sys/amd64/include/pcpu_aux.h: No such file or > > > directory. > > > (kgdb) bt > > > #0 __curthread () at /usr/src/sys/amd64/include/pcpu_aux.h:55 > > > #1 doadump (textdump=1) at ../../../kern/kern_shutdown.c:371 > > > #2 0xffffffff80b83ada in kern_reboot (howto=260) > > > at ../../../kern/kern_shutdown.c:451 > > > #3 0xffffffff80b83f33 in vpanic (fmt=<optimized out>, > > > ap=<optimized out>) > > > at ../../../kern/kern_shutdown.c:880 > > > #4 0xffffffff80b83d53 in panic (fmt=<unavailable>) > > > at ../../../kern/kern_shutdown.c:807 > > > #5 0xffffffff80be7152 in propagate_priority > > > (td=0xfffff80196959740) > > > at ../../../kern/subr_turnstile.c:228 > > > #6 0xffffffff80be7d1c in turnstile_wait (ts=0xfffff8000357a780, > > > owner=<optimized out>, queue=0) at > > > ../../../kern/subr_turnstile.c:785 > > > #7 0xffffffff80b62ca9 in __mtx_lock_sleep (c=0xfffff80003969bd0, > > > v=<optimized out>) at ../../../kern/kern_mutex.c:654 > > > #8 0xffffffff8086fcc0 in ppcintr (arg=0xfffff80003969b00) > > > at ../../../dev/ppc/ppc.c:1546 > > > #9 0xffffffff80b4637c in intr_event_execute_handlers (p=<optimized > > > out>, > > > ie=0xfffff800030d9d00) at ../../../kern/kern_intr.c:1143 > > > #10 ithread_execute_handlers (p=<optimized out>, > > > ie=0xfffff800030d9d00) > > > at ../../../kern/kern_intr.c:1156 > > > #11 ithread_loop (arg=0xfffff800039aa7e0) at > > > ../../../kern/kern_intr.c:1236 > > > #12 0xffffffff80b42e1e in fork_exit ( > > > callout=0xffffffff80b46140 <ithread_loop>, > > > arg=0xfffff800039aa7e0, > > > frame=0xfffffe005ab73d40) at ../../../kern/kern_fork.c:1080 > > > #13 <signal handler called> > > > (kgdb) > > > > > >