panic: kernel diagnostic assertion "__mp_lock_held(&sched_lock, curcpu()) == 0" failed: file "/syzkaller/managers/multicore/kernel/sys/kern/kern_lock.c", line 63 Stopped at db_enter+0xa: popq %rbp TID PID UID PRFLAGS PFLAGS CPU COMMAND db_enter() at db_enter+0xa sys/arch/amd64/amd64/db_interface.c:399 panic() at panic+0x147 sys/kern/subr_prf.c:208 __assert(ffffffff81292154,ffff8000211bf590,ffff8000210c44c8,ffff800000038e80) at __assert+0x24 sys/kern/subr_prf.c:155 _kernel_lock(ffff8000210c44c8,ffff8000211ba000) at _kernel_lock+0x125 sys/kern/kern_lock.c:63 pageflttrap() at pageflttrap+0x6c sys/arch/amd64/amd64/trap.c:163 kerntrap(9) at kerntrap+0x8d sys/arch/amd64/amd64/trap.c:294 alltraps_kern(6,ffff800002ad8000,ffffffffffffffff,0,9,ffff8000210c44c8) at alltraps_kern+0x7b ptsignal(1cee,ffff8000210c44c8,ffff8000210a8cd0) at ptsignal+0x115 sys/kern/kern_sig.c:932 mi_switch() at mi_switch+0x1fb sys/kern/sched_bsd.c:392 sleep_finish(1,ffff8000211bf820) at sleep_finish+0xd3 sys/kern/kern_synch.c:312 sleep_finish_all(ffff8000211bf820,32) at sleep_finish_all+0x22 sleep_finish_timeout sys/kern/kern_synch.c:336 [inline] sleep_finish_all(ffff8000211bf820,32) at sleep_finish_all+0x22 sys/kern/kern_synch.c:157 tsleep(ffff8000210c44c8,3,0,ffff8000210a8d98) at tsleep+0x142 single_thread_set(ffff8000210c44c8,ffff8000210c44c8,0) at single_thread_set+0x28b single_thread_wait sys/kern/kern_sig.c:2039 [inline] single_thread_set(ffff8000210c44c8,ffff8000210c44c8,0) at single_thread_set+0x28b sys/kern/kern_sig.c:2030 exit1(ffff8000210c44c8,9,0) at exit1+0x84 sys/kern/kern_exit.c:137 end trace frame: 0xffff8000211bf9f0, count: 0 https://www.openbsd.org/ddb.html describes the minimum info required in bug reports. Insufficient info makes it difficult to find and fix bugs. ddb{1}> ddb{1}> set $lines = 0 ddb{1}> show panic kernel diagnostic assertion "__mp_lock_held(&sched_lock, curcpu()) == 0" failed: file "/syzkaller/managers/multicore/kernel/sys/kern/kern_lock.c", line 63 ddb{1}> trace db_enter() at db_enter+0xa sys/arch/amd64/amd64/db_interface.c:399 panic() at panic+0x147 sys/kern/subr_prf.c:208 __assert(ffffffff81292154,ffff8000211bf590,ffff8000210c44c8,ffff800000038e80) at __assert+0x24 sys/kern/subr_prf.c:155 _kernel_lock(ffff8000210c44c8,ffff8000211ba000) at _kernel_lock+0x125 sys/kern/kern_lock.c:63 pageflttrap() at pageflttrap+0x6c sys/arch/amd64/amd64/trap.c:163 kerntrap(9) at kerntrap+0x8d sys/arch/amd64/amd64/trap.c:294 alltraps_kern(6,ffff800002ad8000,ffffffffffffffff,0,9,ffff8000210c44c8) at alltraps_kern+0x7b ptsignal(1cee,ffff8000210c44c8,ffff8000210a8cd0) at ptsignal+0x115 sys/kern/kern_sig.c:932 mi_switch() at mi_switch+0x1fb sys/kern/sched_bsd.c:392 sleep_finish(1,ffff8000211bf820) at sleep_finish+0xd3 sys/kern/kern_synch.c:312 sleep_finish_all(ffff8000211bf820,32) at sleep_finish_all+0x22 sleep_finish_timeout sys/kern/kern_synch.c:336 [inline] sleep_finish_all(ffff8000211bf820,32) at sleep_finish_all+0x22 sys/kern/kern_synch.c:157 tsleep(ffff8000210c44c8,3,0,ffff8000210a8d98) at tsleep+0x142 single_thread_set(ffff8000210c44c8,ffff8000210c44c8,0) at single_thread_set+0x28b single_thread_wait sys/kern/kern_sig.c:2039 [inline] single_thread_set(ffff8000210c44c8,ffff8000210c44c8,0) at single_thread_set+0x28b sys/kern/kern_sig.c:2030 exit1(ffff8000210c44c8,9,0) at exit1+0x84 sys/kern/kern_exit.c:137 postsig(100,ffff8000210c44c8) at postsig+0x3ea sigexit sys/kern/kern_sig.c:1488 [inline] postsig(100,ffff8000210c44c8) at postsig+0x3ea sys/kern/kern_sig.c:1420 userret(0) at userret+0x11b sys/kern/kern_sig.c:1870 syscall(0) at syscall+0x54d mi_syscall_return sys/sys/syscall_mi.h:122 [inline] syscall(0) at syscall+0x54d sys/arch/amd64/amd64/trap.c:605 Xsyscall(6,58,b875a035e00,53,0,b86d75e7420) at Xsyscall+0x128 end of kernel end trace frame: 0xb86fb3e2f50, count: -18 ddb{1}> show registers rdi 0xffffffff81e232f8 kprintf_mutex rsi 0xffffffff8164bad9 db_enter+0x9 rbp 0xffff8000211bf4f0 rbx 0xffff8000211bf590 rdx 0xffff800002ad8000 rcx 0x40bc __ALIGN_SIZE+0x30bc rax 0xffff800002ad8000 r8 0xffff8000211bf4c0 r9 0x8080808080808080 r10 0x1e542ec03c3ad9ea r11 0xffffffff81622960 x86_bus_space_io_read_1 r12 0x3000000008 r13 0xffff8000211bf500 r14 0x100 r15 0xffffffff81bf21e1 cmd0646_9_tim_udma+0x1c363 rip 0xffffffff8164bada db_enter+0xa cs 0x8 rflags 0x202 rsp 0xffff8000211bf4f0 ss 0x10 db_enter+0xa: popq %rbp ddb{1}> show proc PROC (syz-executor1) pid=179373 stat=sleep flags process=1000 proc=4002000 pri=50, usrpri=82, nice=20 forw=0x0, list=0xffff8000210c4270,0xffff8000210c4028 process=0xffff8000210a8cd0 user=0xffff8000211ba000, vmspace=0xffffff007f124108 estcpu=36, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND *44263 179373 19761 0 3 0x4003000 suspend syz-executor1 44263 262330 19761 0 2 0x4081080 syz-executor1 31768 34730 99145 0 3 0x80 nanosleep syz-executor0 31768 84448 99145 0 3 0x4000080 fifor syz-executor0 31768 252168 99145 0 3 0x4000080 fsleep syz-executor0 50710 514423 1 0 3 0x100083 ttyin getty 43845 121464 0 0 3 0x14200 bored sosplice 19761 392415 28964 0 3 0x82 nanosleep syz-executor1 99145 235314 28964 0 3 0x82 nanosleep syz-executor0 28964 405970 78921 0 3 0x82 kqread syz-fuzzer 28964 110143 78921 0 3 0x4000082 thrsleep syz-fuzzer 28964 471022 78921 0 3 0x4000082 thrsleep syz-fuzzer 28964 426560 78921 0 3 0x4000082 thrsleep syz-fuzzer 28964 181367 78921 0 3 0x4000082 thrsleep syz-fuzzer 28964 42780 78921 0 3 0x4000082 thrsleep syz-fuzzer 28964 101477 78921 0 3 0x4000082 thrsleep syz-fuzzer 28964 241825 78921 0 3 0x4000082 thrsleep syz-fuzzer 28964 228695 78921 0 3 0x4000082 thrsleep syz-fuzzer 78921 148788 94762 0 3 0x10008a pause ksh 94762 161381 38859 0 3 0x92 select sshd 38859 186313 1 0 3 0x80 select sshd 36648 216732 72605 73 3 0x100090 kqread syslogd 72605 105835 1 0 3 0x100082 netio syslogd 50043 150258 1 77 3 0x100090 poll dhclient 20756 171017 1 0 3 0x80 poll dhclient 62711 128234 0 0 3 0x14200 pgzero zerothread 12472 100713 0 0 3 0x14200 aiodoned aiodoned 1579 2431 0 0 3 0x14200 syncer update 1696 441775 0 0 3 0x14200 cleaner cleaner 87394 429827 0 0 3 0x14200 reaper reaper 69165 278019 0 0 3 0x14200 pgdaemon pagedaemon 48798 17253 0 0 3 0x14200 bored crynlk 15501 363470 0 0 3 0x14200 bored crypto 85377 467287 0 0 3 0x40014200 acpi0 acpi0 35903 38182 0 0 3 0x40014200 idle1 94023 209399 0 0 3 0x14200 bored softnet 94308 477961 0 0 3 0x14200 bored systqmp 42200 325274 0 0 3 0x14200 bored systq 94774 162617 0 0 3 0x40014200 bored softclock 38433 384968 0 0 3 0x40014200 idle0 1 407240 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper