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(ffffffff81520c94,ffff8000211b16c0,ffff8000210b7090,ffff80000002f180) at __assert+0x24 sys/kern/subr_prf.c:155 _kernel_lock(ffff8000210b7090,ffff8000211ac000) 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,ffff8000210b7090) at alltraps_kern+0x7b ptsignal(1889,ffff8000210b7090,ffff8000210a3960) at ptsignal+0x115 sys/kern/kern_sig.c:944 mi_switch() at mi_switch+0x1fb sys/kern/sched_bsd.c:392 sleep_finish(1,ffff8000211b1950) at sleep_finish+0xd3 sys/kern/kern_synch.c:312 sleep_finish_all(ffff8000211b1950,32) at sleep_finish_all+0x22 sleep_finish_timeout sys/kern/kern_synch.c:336 [inline] sleep_finish_all(ffff8000211b1950,32) at sleep_finish_all+0x22 sys/kern/kern_synch.c:157 tsleep(ffff8000210b7090,3,0,ffff8000210a3a28) at tsleep+0x142 single_thread_set(ffff8000210b7090,ffff8000210b7090,0) at single_thread_set+0x28b single_thread_wait sys/kern/kern_sig.c:2051 [inline] single_thread_set(ffff8000210b7090,ffff8000210b7090,0) at single_thread_set+0x28b sys/kern/kern_sig.c:2042 exit1(ffff8000210b7090,9,0) at exit1+0x84 sys/kern/kern_exit.c:137 end trace frame: 0xffff8000211b1b20, 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{0}> ddb{0}> set $lines = 0 ddb{0}> 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{0}> 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(ffffffff81520c94,ffff8000211b16c0,ffff8000210b7090,ffff80000002f180) at __assert+0x24 sys/kern/subr_prf.c:155 _kernel_lock(ffff8000210b7090,ffff8000211ac000) 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,ffff8000210b7090) at alltraps_kern+0x7b ptsignal(1889,ffff8000210b7090,ffff8000210a3960) at ptsignal+0x115 sys/kern/kern_sig.c:944 mi_switch() at mi_switch+0x1fb sys/kern/sched_bsd.c:392 sleep_finish(1,ffff8000211b1950) at sleep_finish+0xd3 sys/kern/kern_synch.c:312 sleep_finish_all(ffff8000211b1950,32) at sleep_finish_all+0x22 sleep_finish_timeout sys/kern/kern_synch.c:336 [inline] sleep_finish_all(ffff8000211b1950,32) at sleep_finish_all+0x22 sys/kern/kern_synch.c:157 tsleep(ffff8000210b7090,3,0,ffff8000210a3a28) at tsleep+0x142 single_thread_set(ffff8000210b7090,ffff8000210b7090,0) at single_thread_set+0x28b single_thread_wait sys/kern/kern_sig.c:2051 [inline] single_thread_set(ffff8000210b7090,ffff8000210b7090,0) at single_thread_set+0x28b sys/kern/kern_sig.c:2042 exit1(ffff8000210b7090,9,0) at exit1+0x84 sys/kern/kern_exit.c:137 postsig(100,ffff8000210b7090) at postsig+0x3ea sigexit sys/kern/kern_sig.c:1500 [inline] postsig(100,ffff8000210b7090) 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(6,58,8baa9c2d600,53,0,8ba9152b1e0) at Xsyscall+0x128 end of kernel end trace frame: 0x8ba87be2ae0, count: -18 ddb{0}> show registers rdi 0xffffffff81e29608 kprintf_mutex rsi 0xffffffff816861a9 db_enter+0x9 rbp 0xffff8000211b1620 rbx 0xffff8000211b16c0 rdx 0xffff800000cd6000 rcx 0x4176 __ALIGN_SIZE+0x3176 rax 0xffff800000cd6000 r8 0xffff8000211b15f0 r9 0x8080808080808080 r10 0x2b935a153e7a8388 r11 0xffffffff818ad7f0 x86_bus_space_io_read_1 r12 0x3000000008 r13 0xffff8000211b1630 r14 0x100 r15 0xffffffff81bf2b31 cmd0646_9_tim_udma+0x1d799 rip 0xffffffff816861aa db_enter+0xa cs 0x8 rflags 0x202 rsp 0xffff8000211b1620 ss 0x10 db_enter+0xa: popq %rbp ddb{0}> show proc PROC (syz-executor0) pid=227450 stat=sleep flags process=1000 proc=4002000 pri=50, usrpri=81, nice=20 forw=0x0, list=0xffff8000210b6280,0xffff8000210b7550 process=0xffff8000210a3960 user=0xffff8000211ac000, vmspace=0xffffff007f124528 estcpu=31, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 47629 398769 82125 0 2 0 syz-executor1 47629 210354 82125 0 2 0x4000000 syz-executor1 38997 249493 85596 0 2 0x4081000 syz-executor0 *38997 227450 85596 0 3 0x4003000 suspend syz-executor0 89968 39613 1 0 3 0x100083 ttyin getty 11981 424403 0 0 3 0x14200 bored sosplice 82125 476574 25718 0 3 0x82 nanosleep syz-executor1 85596 139909 25718 0 3 0x82 wait syz-executor0 25718 118159 26401 0 3 0x82 kqread syz-fuzzer 25718 164200 26401 0 3 0x4000082 nanosleep syz-fuzzer 25718 3915 26401 0 3 0x4000082 thrsleep syz-fuzzer 25718 308083 26401 0 3 0x4000082 thrsleep syz-fuzzer 25718 338473 26401 0 3 0x4000082 thrsleep syz-fuzzer 25718 229298 26401 0 3 0x4000082 thrsleep syz-fuzzer 25718 370949 26401 0 3 0x4000082 thrsleep syz-fuzzer 25718 398405 26401 0 3 0x4000082 thrsleep syz-fuzzer 25718 278682 26401 0 3 0x4000082 thrsleep syz-fuzzer 25718 26025 26401 0 2 0x4000082 syz-fuzzer 26401 161929 75144 0 3 0x10008a pause ksh 75144 453885 48949 0 3 0x92 select sshd 48949 50019 1 0 3 0x80 select sshd 90782 113309 86937 73 3 0x100010 ffs_fsync syslogd 86937 242025 1 0 3 0x100082 netio syslogd 95355 474010 1 77 3 0x100090 poll dhclient 51641 316271 1 0 3 0x80 poll dhclient 2772 29779 0 0 2 0x14200 zerothread 21113 164971 0 0 3 0x14200 aiodoned aiodoned 88481 380773 0 0 3 0x14200 syncer update 87144 1354 0 0 3 0x14200 cleaner cleaner 45585 359247 0 0 3 0x14200 reaper reaper 88418 290514 0 0 3 0x14200 pgdaemon pagedaemon 13000 366578 0 0 3 0x14200 bored crynlk 49780 358539 0 0 3 0x14200 bored crypto 23238 99339 0 0 3 0x40014200 acpi0 acpi0 17425 409663 0 0 3 0x40014200 idle1 47407 219150 0 0 3 0x14200 bored softnet 77763 202687 0 0 3 0x14200 bored systqmp 22215 65437 0 0 3 0x14200 bored systq 33727 99078 0 0 3 0x40014200 bored softclock 44603 484823 0 0 3 0x40014200 idle0 1 355027 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper