panic: Assertion in_epoch(net_epoch_preempt) failed at ... src/sys/net/if.c:3694

[David Wolfskill]

On Tue, Oct 08, 2019 at 05:15:19AM -0700, David Wolfskill wrote:
> This was on my laptop (build machine, which was updated in parallel,
> but uses a different NIC, had no issues) after a src update from
> r353176 to r353298; laptop's NIC is wlan(4) (which is iwn(4), in
> this case).

After restoring the /boot/*.old set, I was able to reboot & update from
r353298 to r353336.  The subsequent reboot seemed OK ... until the
keyboard & mouse were enabled (under X11; I use xdm on the laptop).

Then I got a slightly different panic:

panic: Assertion in_epoch(net_epoch_preempt) failed at /usr/src/sys/net/if.c:356

Backtrace:

panic: Assertion in_epoch(net_epoch_preempt) failed at /usr/src/sys/net/if.c:356
cpuid = 0
time = 1570621553
KDB: stack backtrace:
db_trace_self_wrapper() at 0xffffffff8049ebab = db_trace_self_wrapper+0x2b/frame 0xfffffe1072956580
vpanic() at 0xffffffff80b978fd = vpanic+0x19d/frame 0xfffffe10729565d0
panic() at 0xffffffff80b97693 = panic+0x43/frame 0xfffffe1072956630
if_ref() at 0xffffffff80ca1b10 = if_ref/frame 0xfffffe1072956650
sysctl_ifdata() at 0xffffffff80cb247d = sysctl_ifdata+0x4d/frame 0xfffffe1072956760
sysctl_root_handler_locked() at 0xffffffff80ba714b = sysctl_root_handler_locked+0x7b/frame 0xfffffe10729567a0
sysctl_root() at 0xffffffff80ba64dc = sysctl_root+0x20c/frame 0xfffffe1072956820
userland_sysctl() at 0xffffffff80ba6bab = userland_sysctl+0x17b/frame 0xfffffe10729568d0
sys___sysctl() at 0xffffffff80ba69ef = sys___sysctl+0x5f/frame 0xfffffe1072956980
amd64_syscall() at 0xffffffff810480f4 = amd64_syscall+0x2d4/frame 0xfffffe1072956ab0
fast_syscall_common() at 0xffffffff8101eaa0 = fast_syscall_common+0x101/frame 0xfffffe1072956ab0
--- syscall (202, FreeBSD ELF64, sys___sysctl), rip = 0x8014d4d2a, rsp = 0x7fffffffeaa8, rbp = 0x7fffffffeae0 ---
KDB: enter: panic

> The ddb "dump" command recorded a dump, which I managed to capture; the
> information may be found at
> http://www.catwhisker.org/~david/FreeBSD/head/r353298/

This one is at http://www.catwhisker.org/~david/FreeBSD/head/r353336

As before, the (headless) build machine had no issues that I could see.

Peace,
david
-- 
David H. Wolfskill				david at catwhisker.org
I am amazed that anyone would condone what Trunp has publicly admitted he did.

See http://www.catwhisker.org/~david/publickey.gpg for my public key.
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