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(ffffffff819ccee4,ffff8000211b5960,ffff8000210c4270,ffff800000038e80) at __assert+0x24 sys/kern/subr_prf.c:155 _kernel_lock(ffff8000210c4270,ffff8000211b0000) 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,ffff800000cd6000,ffffffffffffffff,0,9,ffff8000210c4270) at alltraps_kern+0x7b ptsignal(16dd,ffff8000210c4270,ffff8000210a8cb8) at ptsignal+0x115 sys/kern/kern_sig.c:944 mi_switch() at mi_switch+0x1fb sys/kern/sched_bsd.c:392 sleep_finish(1,ffff8000211b5bf0) at sleep_finish+0xd3 sys/kern/kern_synch.c:312 sleep_finish_all(ffff8000211b5bf0,32) at sleep_finish_all+0x22 sleep_finish_timeout sys/kern/kern_synch.c:336 [inline] sleep_finish_all(ffff8000211b5bf0,32) at sleep_finish_all+0x22 sys/kern/kern_synch.c:157 tsleep(ffff8000210c4270,3,0,ffff8000210a8d80) at tsleep+0x142 single_thread_set(ffff8000210c4270,ffff8000210c4270,0) at single_thread_set+0x28b single_thread_wait sys/kern/kern_sig.c:2051 [inline] single_thread_set(ffff8000210c4270,ffff8000210c4270,0) at single_thread_set+0x28b sys/kern/kern_sig.c:2042 exit1(ffff8000210c4270,9,0) at exit1+0x84 sys/kern/kern_exit.c:137 end trace frame: 0xffff8000211b5dc0, 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(ffffffff819ccee4,ffff8000211b5960,ffff8000210c4270,ffff800000038e80) at __assert+0x24 sys/kern/subr_prf.c:155 _kernel_lock(ffff8000210c4270,ffff8000211b0000) 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,ffff800000cd6000,ffffffffffffffff,0,9,ffff8000210c4270) at alltraps_kern+0x7b ptsignal(16dd,ffff8000210c4270,ffff8000210a8cb8) at ptsignal+0x115 sys/kern/kern_sig.c:944 mi_switch() at mi_switch+0x1fb sys/kern/sched_bsd.c:392 sleep_finish(1,ffff8000211b5bf0) at sleep_finish+0xd3 sys/kern/kern_synch.c:312 sleep_finish_all(ffff8000211b5bf0,32) at sleep_finish_all+0x22 sleep_finish_timeout sys/kern/kern_synch.c:336 [inline] sleep_finish_all(ffff8000211b5bf0,32) at sleep_finish_all+0x22 sys/kern/kern_synch.c:157 tsleep(ffff8000210c4270,3,0,ffff8000210a8d80) at tsleep+0x142 single_thread_set(ffff8000210c4270,ffff8000210c4270,0) at single_thread_set+0x28b single_thread_wait sys/kern/kern_sig.c:2051 [inline] single_thread_set(ffff8000210c4270,ffff8000210c4270,0) at single_thread_set+0x28b sys/kern/kern_sig.c:2042 exit1(ffff8000210c4270,9,0) at exit1+0x84 sys/kern/kern_exit.c:137 postsig(100,ffff8000210c4270) at postsig+0x3ea sigexit sys/kern/kern_sig.c:1500 [inline] postsig(100,ffff8000210c4270) at postsig+0x3ea sys/kern/kern_sig.c:1432 userret(0) at userret+0x11b sys/kern/kern_sig.c:1882 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(6,58,55549cf6000,53,0,554f8520e20) at Xsyscall+0x128 end of kernel end trace frame: 0x55552780390, count: -18 ddb{1}> show registers rdi 0xffffffff81e4ccd8 kprintf_mutex rsi 0xffffffff811dd9b9 db_enter+0x9 rbp 0xffff8000211b58c0 rbx 0xffff8000211b5960 rdx 0xffff800000cd6000 rcx 0x43cd __ALIGN_SIZE+0x33cd rax 0xffff800000cd6000 r8 0xffff8000211b5890 r9 0x8080808080808080 r10 0xbf5a024ab084b0ec r11 0xffffffff811311c0 x86_bus_space_io_read_1 r12 0x3000000008 r13 0xffff8000211b58d0 r14 0x100 r15 0xffffffff81bf41d6 cmd0646_9_tim_udma+0x205dc rip 0xffffffff811dd9ba db_enter+0xa cs 0x8 rflags 0x202 rsp 0xffff8000211b58c0 ss 0x10 db_enter+0xa: popq %rbp ddb{1}> show proc PROC (syz-executor0) pid=14724 stat=sleep flags process=1000 proc=4002000 pri=50, usrpri=86, nice=20 forw=0x0, list=0xffff8000210c5c38,0xffffffff81ed93f0 process=0xffff8000210a8cb8 user=0xffff8000211b0000, vmspace=0xffffff007f125c60 estcpu=36, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 27952 268183 42845 0 2 0x4081000 syz-executor0 *27952 14724 42845 0 3 0x4003000 suspend syz-executor0 79126 502304 11340 0 2 0 syz-executor1 79126 55896 11340 0 3 0x4000080 ttyout syz-executor1 79126 438035 11340 0 2 0x4000000 syz-executor1 96029 157117 1 0 3 0x100083 ttyin getty 89563 502565 0 0 3 0x14200 bored sosplice 11340 280911 92746 0 3 0x82 nanosleep syz-executor1 42845 331610 92746 0 3 0x82 nanosleep syz-executor0 92746 99217 36247 0 3 0x82 thrsleep syz-fuzzer 92746 59761 36247 0 3 0x4000082 thrsleep syz-fuzzer 92746 509311 36247 0 3 0x4000082 thrsleep syz-fuzzer 92746 150692 36247 0 3 0x4000082 thrsleep syz-fuzzer 92746 131601 36247 0 3 0x4000082 thrsleep syz-fuzzer 92746 59725 36247 0 3 0x4000082 thrsleep syz-fuzzer 92746 372072 36247 0 3 0x4000082 thrsleep syz-fuzzer 92746 286585 36247 0 3 0x4000082 thrsleep syz-fuzzer 92746 50109 36247 0 3 0x4000082 kqread syz-fuzzer 36247 367320 45283 0 3 0x10008a pause ksh 45283 115159 82349 0 3 0x92 select sshd 82349 133041 1 0 3 0x80 select sshd 8834 280564 46236 73 3 0x100090 kqread syslogd 46236 89123 1 0 3 0x100082 netio syslogd 12237 201704 1 77 3 0x100090 poll dhclient 40235 432590 1 0 3 0x80 poll dhclient 4178 50474 0 0 2 0x14200 zerothread 13709 340177 0 0 3 0x14200 aiodoned aiodoned 74813 12579 0 0 3 0x14200 syncer update 68412 519580 0 0 3 0x14200 cleaner cleaner 12500 374159 0 0 3 0x14200 reaper reaper 80265 25260 0 0 3 0x14200 pgdaemon pagedaemon 27144 282472 0 0 3 0x14200 bored crynlk 41808 422808 0 0 3 0x14200 bored crypto 70740 456537 0 0 3 0x40014200 acpi0 acpi0 28547 139131 0 0 3 0x40014200 idle1 14364 134607 0 0 3 0x14200 bored softnet 21277 335552 0 0 3 0x14200 bored systqmp 20632 18916 0 0 3 0x14200 bored systq 67899 30491 0 0 3 0x40014200 bored softclock 55252 430350 0 0 3 0x40014200 idle0 1 212466 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper