freebsd boot error: panic: Assertion in_epoch(net_epoch_preempt) failed at /syzkaller/managers/main/kernel/sys/net/if.c:LINE

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 918670a5 Define macro VM_MAP_ENTRY_FOREACH for enumerating..
git tree: freebsd
console output: https://syzkaller.appspot.com/x/log.txt?x=10db5620e00000
dashboard link: https://syzkaller.appspot.com/bug?extid=1c5b2b0210873ac4f8c3

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+1c5b2b...@syzkaller.appspotmail.com

panic: Assertion in_epoch(net_epoch_preempt) failed at
/syzkaller/managers/main/kernel/sys/net/if.c:3694
cpuid = 1
time = 1570530127
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x47/frame
0xfffffe001a110850
vpanic() at vpanic+0x1e0/frame 0xfffffe001a1108b0
panic() at panic+0x43/frame 0xfffffe001a110910
if_delmulti_ifma_flags() at if_delmulti_ifma_flags+0x1af/frame
0xfffffe001a110950
inm_release_task() at inm_release_task+0x345/frame 0xfffffe001a1109c0
gtaskqueue_run_locked() at gtaskqueue_run_locked+0x13e/frame
0xfffffe001a110a20
gtaskqueue_thread_loop() at gtaskqueue_thread_loop+0xdd/frame
0xfffffe001a110a60
fork_exit() at fork_exit+0xb0/frame 0xfffffe001a110ab0
fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe001a110ab0
--- trap 0, rip = 0, rsp = 0, rbp = 0 ---
KDB: enter: panic
[ thread pid 0 tid 100005 ]
Stopped at kdb_enter+0x6a: movq $0,kdb_why
db>


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.