Fatal trap 12: page fault in link_elf_search_symbol

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 23ca26e1 Allow dcons(4) to be unloaded when loaded as a mo..
git tree: freebsd
console output: https://syzkaller.appspot.com/x/log.txt?x=134e6c00a00000
dashboard link: https://syzkaller.appspot.com/bug?extid=9764fd4cb97155115928

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+9764fd...@syzkaller.appspotmail.com

Fatal trap 12: page fault while in kernel mode
cpuid = 1; apic id = 01
fault virtual address = 0x0
fault code = supervisor read data , page not present
instruction pointer = 0x20:0xffffffff818e523d
stack pointer = 0x28:0xfffffe0021272290
frame pointer = 0x28:0xfffffe00212722f0
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 = 807 (syz-executor.3)
trap number = 12
panic: page fault
cpuid = 1
time = 1557488545
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x47/frame
0xfffffe0021271ef0
vpanic() at vpanic+0x1e0/frame 0xfffffe0021271f50
panic() at panic+0x43/frame 0xfffffe0021271fb0
trap_fatal() at trap_fatal+0x4c6/frame 0xfffffe0021272030
trap_pfault() at trap_pfault+0x9f/frame 0xfffffe00212720a0
trap() at trap+0x44d/frame 0xfffffe00212721c0
calltrap() at calltrap+0x8/frame 0xfffffe00212721c0
--- trap 0xc, rip = 0xffffffff818e523d, rsp = 0xfffffe0021272290, rbp =
0xfffffe00212722f0 ---
link_elf_search_symbol() at link_elf_search_symbol+0x7d/frame
0xfffffe00212722f0
linker_ddb_search_symbol() at linker_ddb_search_symbol+0xa7/frame
0xfffffe0021272350
stack_sbuf_print_ddb() at stack_sbuf_print_ddb+0x6a/frame 0xfffffe00212723b0
witness_debugger() at witness_debugger+0xa7/frame 0xfffffe00212724e0
witness_checkorder() at witness_checkorder+0xf72/frame 0xfffffe0021272590
_sx_xlock() at _sx_xlock+0xb3/frame 0xfffffe00212725e0
inp_setmoptions() at inp_setmoptions+0x17c9/frame 0xfffffe00212727c0
ip_ctloutput() at ip_ctloutput+0x80f/frame 0xfffffe0021272810
rip_ctloutput() at rip_ctloutput+0x2c9/frame 0xfffffe0021272850
sosetopt() at sosetopt+0x101/frame 0xfffffe00212728d0
kern_setsockopt() at kern_setsockopt+0x158/frame 0xfffffe0021272950
sys_setsockopt() at sys_setsockopt+0x33/frame 0xfffffe0021272980
amd64_syscall() at amd64_syscall+0x436/frame 0xfffffe0021272ab0
fast_syscall_common() at fast_syscall_common+0x101/frame 0xfffffe0021272ab0
--- syscall (198, FreeBSD ELF64, nosys), rip = 0x41309a, rsp =
0x7fffdfffdf38, rbp = 0x5 ---
KDB: enter: panic
[ thread pid 807 tid 100118 ]
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.