panic: _mtx_lock_sleep: recursed on non-recursive mutex rtentry @ /syzkaller/managers/i386/kernel/sys/net/route.c:470

cpuid = 0
time = 1559577095
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x47/frame 0xfffffe0020e6cfa0
vpanic() at vpanic+0x1e0/frame 0xfffffe0020e6d000
panic() at panic+0x43/frame 0xfffffe0020e6d060
__mtx_lock_sleep() at __mtx_lock_sleep+0x71a/frame 0xfffffe0020e6d100
__mtx_lock_flags() at __mtx_lock_flags+0x157/frame 0xfffffe0020e6d160
rtalloc1_fib() at rtalloc1_fib+0x16e/frame 0xfffffe0020e6d270
ifa_ifwithroute() at ifa_ifwithroute+0x136/frame 0xfffffe0020e6d2b0
rt_getifa_fib() at rt_getifa_fib+0x255/frame 0xfffffe0020e6d320
rtrequest1_fib() at rtrequest1_fib+0xe3f/frame 0xfffffe0020e6d440
route_output() at route_output+0x1259/frame 0xfffffe0020e6d6c0
sosend_generic() at sosend_generic+0x73d/frame 0xfffffe0020e6d790
sosend() at sosend+0xc6/frame 0xfffffe0020e6d800
kern_sendit() at kern_sendit+0x35e/frame 0xfffffe0020e6d8b0
sendit() at sendit+0x225/frame 0xfffffe0020e6d910
sys_sendto() at sys_sendto+0x5c/frame 0xfffffe0020e6d970
ia32_syscall() at ia32_syscall+0x452/frame 0xfffffe0020e6dab0
int0x80_syscall_common() at int0x80_syscall_common+0x9c/frame 0x8142e4c
KDB: enter: panic
[ thread pid 788 tid 100096 ]
Stopped at      kdb_enter+0x6a: movq    $0,kdb_why