witness: acquiring duplicate lock of same type: "&sc->sc_lock" 1st wsmuxlk @ /syzkaller/managers/multicore/kernel/sys/dev/wscons/wsmux.c:245 2nd wsmuxlk @ /syzkaller/managers/multicore/kernel/sys/dev/wscons/wsmux.c:245 Starting stack trace... witness_checkorder(ffff80000197dcd0,1,ffffffff81f33463,f5,0) at witness_checkorder+0xe14 witness_debugger sys/kern/subr_witness.c:2650 [inline] witness_checkorder(ffff80000197dcd0,1,ffffffff81f33463,f5,0) at witness_checkorder+0xe14 sys/kern/subr_witness.c:926 _rw_enter_read(ffff80000197dcc0,ffffffff81f33463,f5) at _rw_enter_read+0x80 sys/kern/kern_rwlock.c:102 wsmux_mux_open(ffff80000197dc00,ffff800000026d50) at wsmux_mux_open+0x82 wsmux_do_open sys/dev/wscons/wsmux.c:246 [inline] wsmux_mux_open(ffff80000197dc00,ffff800000026d50) at wsmux_mux_open+0x82 sys/dev/wscons/wsmux.c:228 wsmuxopen(4500,1,2000,ffff800020b439e0) at wsmuxopen+0x179 wsmux_do_open sys/dev/wscons/wsmux.c:258 [inline] wsmuxopen(4500,1,2000,ffff800020b439e0) at wsmuxopen+0x179 sys/dev/wscons/wsmux.c:204 spec_open(ffff800020c3b220) at spec_open+0x217 sys/kern/spec_vnops.c:158 VOP_OPEN(fffffd80707e34f0,1,fffffd807f7c76c0,ffff800020b439e0) at VOP_OPEN+0x76 sys/kern/vfs_vops.c:153 vn_open(ffff800020c3b410,1,0) at vn_open+0x4c6 sys/kern/vfs_vnops.c:174 doopenat(ffff800020b439e0,ffffff9c,200001c0,0,0,ffff800020c3b650) at doopenat+0x2be sys/kern/vfs_syscalls.c:1045 syscall(ffff800020c3b700) at syscall+0x5ac mi_syscall sys/sys/syscall_mi.h:99 [inline] syscall(ffff800020c3b700) at syscall+0x5ac sys/arch/amd64/amd64/trap.c:574 Xsyscall(6,0,ffffffffffffffa8,0,3,299ddbb4010) at Xsyscall+0x128 end of kernel end trace frame: 0x29c4b09d2c0, count: 247 End of stack trace. Stopped at db_enter+0x18: addq $0x8,%rsp