Re: at SVN r347375, terminating/restarting openvpn on tap causes panic

  Michael,

On Thu, May 09, 2019 at 10:25:37AM -0500, Kyle Evans wrote:
K> > #0  doadump () at src/sys/amd64/include/pcpu.h:241
K> > #1  0xffffffff808393c8 in kern_reboot (howto=260) at
K> > /usr/src/sys/kern/kern_shutdown.c:470
K> > #2  0xffffffff80839826 in vpanic (fmt=<value optimized out>, ap=<value
K> > optimized out>) at /usr/src/sys/kern/kern_shutdown.c:896
K> > #3  0xffffffff80839663 in panic (fmt=<value optimized out>) at
K> > /usr/src/sys/kern/kern_shutdown.c:823
K> > #4  0xffffffff80c318a6 in trap_fatal (frame=0xfffffe0072b14510, eva=156)
K> > at /usr/src/sys/amd64/amd64/trap.c:946
K> > #5  0xffffffff80c31c59 in trap_pfault (frame=0xfffffe0072b14510,
K> > usermode=0) at src/sys/amd64/include/cpufunc.h:423
K> > #6  0xffffffff80c30fde in trap (frame=0xfffffe0072b14510) at
K> > /usr/src/sys/amd64/amd64/trap.c:441
K> > #7  0xffffffff80c0d4b5 in calltrap () at
K> > /usr/src/sys/amd64/amd64/exception.S:232
K> > #8  0xffffffff80a15377 in ip_output (m=<value optimized out>, opt=<value
K> > optimized out>, ro=0x0, flags=0, imo=0xfffffe0072b14780, inp=0x0) at
K> > /usr/src/sys/netinet/ip_output.c:362
K> > #9  0xffffffff809ffea4 in igmp_intr (m=<value optimized out>) at
K> > /usr/src/sys/netinet/igmp.c:3455
K> > #10 0xffffffff80975a0f in netisr_dispatch_src (proto=2, source=<value
K> > optimized out>, m=<value optimized out>) at /usr/src/sys/net/netisr.c:1122
K> > #11 0xffffffff809fe07a in igmp_fasttimo () at
K> > /usr/src/sys/netinet/igmp.c:496
K> > #12 0xffffffff808c5854 in pffasttimo (arg=<value optimized out>) at
K> > /usr/src/sys/kern/uipc_domain.c:521
K> > #13 0xffffffff80853df3 in softclock_call_cc (c=0xffffffff813f7f48,
K> > cc=0xffffffff814c9ac0, direct=0) at /usr/src/sys/kern/kern_timeout.c:731
K> > #14 0xffffffff808542b9 in softclock (arg=0xffffffff814c9ac0) at
K> > /usr/src/sys/kern/kern_timeout.c:869
K> > #15 0xffffffff807fd0c4 in ithread_loop (arg=<value optimized out>) at
K> > /usr/src/sys/kern/kern_intr.c:1129
K> > #16 0xffffffff807f9f33 in fork_exit (callout=0xffffffff807fcef0
K> > <ithread_loop>, arg=0xfffff800025f10a0, frame=0xfffffe0072b14ac0) at
K> > /usr/src/sys/kern/kern_fork.c:1058
K> > #17 0xffffffff80c0e4ae in fork_trampoline () at
K> > /usr/src/sys/amd64/amd64/exception.S:995
K> > #18 0x0000000000000000 in ?? ()
K> >
K> 
K> Ah, I misread your backtrace (and forgot the proper tap detachment
K> from my previous patch, so that's fixed/committed anyways). CC'ing
K> Gleb for further triage as committer of r347375 that touched things in
K> this path.

Michael, can you please dump a core and look at it in kgdb? Line 362 in
ip_output() really belongs to part that had minimal change with r347375.
So I need more details. Can you please print out in kgdb the following
variables: imo, ifp, ia?

-- 
Gleb Smirnoff