On Wed, Mar 08, 2017 at 09:00:17PM -0800, Bryan Drewery wrote: > I'm on r314708. I hit ^C while running 'kyua test' in /usr/tests/bin/pwait. > > > panic: tdsendsignal: ksi on queue > > cpuid = 10 > > > #10 kdb_enter (why=0xffffffff814488f5 "panic", msg=<optimized out>) at > > /usr/src/sys/kern/subr_kdb.c:444 > > #11 0xffffffff80a577f3 in vpanic (fmt=<optimized out>, > > ap=0xfffffe35601a3620) at /usr/src/sys/kern/kern_shutdown.c:772 > > #12 0xffffffff80a5764f in _kassert_panic (fatal=1, fmt=0xffffffff81448fd7 > > "%s: ksi on queue") at /usr/src/sys/kern/kern_shutdown.c:669 > > #13 0xffffffff80a5c843 in tdsendsignal (p=0xfffff80c39389a80, td=0x0, > > sig=20, ksi=0xfffff803888a2bd0) at /usr/src/sys/kern/kern_sig.c:2095 > > #14 0xffffffff80a13828 in exit1 (td=<optimized out>, rval=<optimized out>, > > signo=<optimized out>) at /usr/src/sys/kern/kern_exit.c:459 > > #15 0xffffffff80a5b28c in sigexit (td=0xfffff802f0bee000, sig=9) at > > /usr/src/sys/kern/kern_sig.c:3081 > > #16 0xffffffff80a5b88e in postsig (sig=9) at > > /usr/src/sys/kern/kern_sig.c:2992 > > #17 0xffffffff80a5b56b in kern_sigsuspend (td=0xfffff802f0bee000, mask=...) > > at /usr/src/sys/kern/kern_sig.c:1515 > > #18 0xffffffff80a5b441 in sys_sigsuspend (td=0xfffff802f0bee000, > > uap=<optimized out>) at /usr/src/sys/kern/kern_sig.c:1479 > > #19 0xffffffff80ee04da in syscallenter (td=0xfffff802f0bee000, > > sa=<optimized out>) at > > /usr/src/sys/amd64/amd64/../../kern/subr_syscall.c:135 > > #20 amd64_syscall (td=0xfffff802f0bee000, traced=0) at > > /usr/src/sys/amd64/amd64/trap.c:902 > > > > (kgdb) frame 18 > > #18 0xffffffff80a5b441 in sys_sigsuspend (td=0xfffff802f0bee000, > > uap=<optimized out>) at /usr/src/sys/kern/kern_sig.c:1479 > > 1479 return (kern_sigsuspend(td, mask)); > > > (kgdb) p td->td_proc->p_comm > > $3 = "timeout", '\000' <repeats 12 times> > > > (kgdb) frame 13 > > #13 0xffffffff80a5c843 in tdsendsignal (p=0xfffff80c39389a80, td=0x0, > > sig=20, ksi=0xfffff803888a2bd0) at /usr/src/sys/kern/kern_sig.c:2095 > > 2095 KASSERT(ksi == NULL || !KSI_ONQ(ksi), ("%s: ksi on queue", > > __func__)); > > (kgdb) p *ksi > > $4 = {ksi_link = {tqe_next = 0x0, tqe_prev = 0xfffff80c39389c58}, ksi_info > > = {si_signo = 20, si_errno = 0, si_code = 2, si_pid = 90903, si_uid = 0, > > si_status = 9, si_addr = 0x0, si_value = { > > sival_int = 0, sival_ptr = 0x0, sigval_int = 0, sigval_ptr = 0x0}, > > _reason = {_fault = {_trapno = 0}, _timer = {_timerid = 0, _overrun = 0}, > > _mesgq = {_mqd = 0}, _poll = {_band = 0}, __spare__ = { > > __spare1__ = 0, __spare2__ = {0, 0, 0, 0, 0, 0, 0}}}}, ksi_flags = > > 6, ksi_sigq = 0xfffff80c39389c28} > > > (kgdb) p *ksi->ksi_sigq > > $6 = {sq_signals = {__bits = {524288, 0, 0, 0}}, sq_kill = {__bits = {0, 0, > > 0, 0}}, sq_ptrace = {__bits = {0, 0, 0, 0}}, sq_list = {tqh_first = > > 0xfffff803888a2bd0, tqh_last = 0xfffff803888a2bd0},
Yes, there is a race, apparently, with the child zombie still not finishing sending the SIGCHLD to the parent and parent exiting. The following should fix the issue, but I do not think that reproducing the problem is easy. diff --git a/sys/kern/kern_exit.c b/sys/kern/kern_exit.c index c524fe5df37..ba5ff84e9de 100644 --- a/sys/kern/kern_exit.c +++ b/sys/kern/kern_exit.c @@ -189,6 +189,7 @@ exit1(struct thread *td, int rval, int signo) { struct proc *p, *nq, *q, *t; struct thread *tdt; + ksiginfo_t ksi; mtx_assert(&Giant, MA_NOTOWNED); KASSERT(rval == 0 || signo == 0, ("exit1 rv %d sig %d", rval, signo)); @@ -456,7 +457,12 @@ exit1(struct thread *td, int rval, int signo) proc_reparent(q, q->p_reaper); if (q->p_state == PRS_ZOMBIE) { PROC_LOCK(q->p_reaper); - pksignal(q->p_reaper, SIGCHLD, q->p_ksi); + if (q->p_ksi != NULL) { + ksiginfo_init(&ksi); + ksiginfo_copy(q->p_ksi, &ksi); + } + pksignal(q->p_reaper, SIGCHLD, q->p_ksi != + NULL ? &ksi : NULL); PROC_UNLOCK(q->p_reaper); } } else { _______________________________________________ freebsd-current@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"