Fatal trap 9: general protection fault in memcmp

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 8d42a256 powerpc64: Fix switch panic from cpu_throw()
git tree: freebsd
console output: https://syzkaller.appspot.com/x/log.txt?x=14489050a00000
dashboard link: https://syzkaller.appspot.com/bug?extid=4ba2fabecb5e1e2e05df

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+4ba2fa...@syzkaller.appspotmail.com

Fatal trap 9: general protection fault while in kernel mode
cpuid = 1; apic id = 01
instruction pointer = 0x20:0xffffffff81715bb1
stack pointer = 0x28:0xfffffe002d8b3540
frame pointer = 0x28:0xfffffe002d8b3540
code segment = base 0x0, limit 0xfffff, type 0x1b
= DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags = interrupt enabled, resume, IOPL = 0
current process = 13556 (syz-executor.1)
trap number = 9
panic: general protection fault
cpuid = 1
time = 91
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x47/frame
0xfffffe002d8b3210
vpanic() at vpanic+0x1e0/frame 0xfffffe002d8b3270
panic() at panic+0x43/frame 0xfffffe002d8b32d0
trap_fatal() at trap_fatal+0x4c6/frame 0xfffffe002d8b3350
trap() at trap+0xba/frame 0xfffffe002d8b3470
calltrap() at calltrap+0x8/frame 0xfffffe002d8b3470
--- trap 0x9, rip = 0xffffffff81715bb1, rsp = 0xfffffe002d8b3540, rbp =
0xfffffe002d8b3540 ---
memcmp() at memcmp+0xa1/frame 0xfffffe002d8b3540
authunix_create() at authunix_create+0x25b/frame 0xfffffe002d8b3800
sys_nlm_syscall() at sys_nlm_syscall+0xed/frame 0xfffffe002d8b3980
amd64_syscall() at amd64_syscall+0x436/frame 0xfffffe002d8b3ab0
fast_syscall_common() at fast_syscall_common+0x101/frame 0xfffffe002d8b3ab0
--- syscall (154, FreeBSD ELF64, sys_nlm_syscall), rip = 0x20000010, rsp =
0x7fffdfffdeb8, rbp = 0x81 ---
KDB: enter: panic
[ thread pid 13556 tid 101469 ]
Stopped at kdb_enter+0x6a: movq $0,kdb_why


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[syzbot]

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