panic: sx_xlock() of destroyed sx @ /syzkaller/managers/i386/kernel/sys/kern/uipc_sockbuf.c:285
cpuid = 0
time = 1559705166
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x47/frame 0xfffffe0020f265d0
vpanic() at vpanic+0x1e0/frame 0xfffffe0020f26630
panic() at panic+0x43/frame 0xfffffe0020f26690
_sx_xlock() at _sx_xlock+0x1c9/frame 0xfffffe0020f266e0
sosend_generic() at sosend_generic+0x1a0/frame 0xfffffe0020f267b0
sosend() at sosend+0xc6/frame 0xfffffe0020f26820
soo_write() at soo_write+0x61/frame 0xfffffe0020f26860
dofilewrite() at dofilewrite+0xfd/frame 0xfffffe0020f268c0
kern_writev() at kern_writev+0x66/frame 0xfffffe0020f26900
sys_write() at sys_write+0xd2/frame 0xfffffe0020f26970
ia32_syscall() at ia32_syscall+0x452/frame 0xfffffe0020f26ab0
int0x80_syscall_common() at int0x80_syscall_common+0x9c/frame 0x8143413
KDB: enter: panic
[ thread pid 18578 tid 100769 ]
Stopped at      kdb_enter+0x6a: movq    $0,kdb_why