panic: kernel diagnostic assertion "__mp_lock_held(&sched_lock, curcpu()) == 0" failed: file "/syzkaller/managers/setuid/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(ffffffff81866be4,ffff8000211c7660,ffff8000210a2018,ffff80000002f180) at __assert+0x24 sys/kern/subr_prf.c:155 _kernel_lock(ffff8000210a2018,ffff8000211c2000) 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,ffff800000ad6000,ffffffffffffffff,0,9,ffff8000210a2018) at alltraps_kern+0x7b ptsignal(2210,ffff8000210a2018,ffff8000210cb308) at ptsignal+0x115 sys/kern/kern_sig.c:944 mi_switch() at mi_switch+0x1fb sys/kern/sched_bsd.c:392 sleep_finish(1,ffff8000211c78f0) at sleep_finish+0xd3 sys/kern/kern_synch.c:312 sleep_finish_all(ffff8000211c78f0,32) at sleep_finish_all+0x22 sleep_finish_timeout sys/kern/kern_synch.c:336 [inline] sleep_finish_all(ffff8000211c78f0,32) at sleep_finish_all+0x22 sys/kern/kern_synch.c:157 tsleep(ffff8000210a2018,3,0,ffff8000210cb3d0) at tsleep+0x142 single_thread_set(ffff8000210a2018,ffff8000210a2018,0) at single_thread_set+0x28b single_thread_wait sys/kern/kern_sig.c:2051 [inline] single_thread_set(ffff8000210a2018,ffff8000210a2018,0) at single_thread_set+0x28b sys/kern/kern_sig.c:2042 exit1(ffff8000210a2018,9,0) at exit1+0x84 sys/kern/kern_exit.c:137 end trace frame: 0xffff8000211c7ac0, 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/setuid/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(ffffffff81866be4,ffff8000211c7660,ffff8000210a2018,ffff80000002f180) at __assert+0x24 sys/kern/subr_prf.c:155 _kernel_lock(ffff8000210a2018,ffff8000211c2000) 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,ffff800000ad6000,ffffffffffffffff,0,9,ffff8000210a2018) at alltraps_kern+0x7b ptsignal(2210,ffff8000210a2018,ffff8000210cb308) at ptsignal+0x115 sys/kern/kern_sig.c:944 mi_switch() at mi_switch+0x1fb sys/kern/sched_bsd.c:392 sleep_finish(1,ffff8000211c78f0) at sleep_finish+0xd3 sys/kern/kern_synch.c:312 sleep_finish_all(ffff8000211c78f0,32) at sleep_finish_all+0x22 sleep_finish_timeout sys/kern/kern_synch.c:336 [inline] sleep_finish_all(ffff8000211c78f0,32) at sleep_finish_all+0x22 sys/kern/kern_synch.c:157 tsleep(ffff8000210a2018,3,0,ffff8000210cb3d0) at tsleep+0x142 single_thread_set(ffff8000210a2018,ffff8000210a2018,0) at single_thread_set+0x28b single_thread_wait sys/kern/kern_sig.c:2051 [inline] single_thread_set(ffff8000210a2018,ffff8000210a2018,0) at single_thread_set+0x28b sys/kern/kern_sig.c:2042 exit1(ffff8000210a2018,9,0) at exit1+0x84 sys/kern/kern_exit.c:137 postsig(100,ffff8000210a2018) at postsig+0x3ea sigexit sys/kern/kern_sig.c:1500 [inline] postsig(100,ffff8000210a2018) 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(6,58,4b39f518200,53,0,4b48475a0c0) at Xsyscall+0x128 end of kernel end trace frame: 0x4b3cd73a0d0, count: -18 ddb{0}> show registers rdi 0xffffffff81e46760 kprintf_mutex rsi 0xffffffff81aee3b9 db_enter+0x9 rbp 0xffff8000211c75c0 rbx 0xffff8000211c7660 rdx 0xffff800000ad6000 rcx 0x40e8 __ALIGN_SIZE+0x30e8 rax 0xffff800000ad6000 r8 0xffff8000211c7590 r9 0x8080808080808080 r10 0xbc5b9be8a05b3954 r11 0xffffffff81112fe0 x86_bus_space_io_read_1 r12 0x3000000008 r13 0xffff8000211c75d0 r14 0x100 r15 0xffffffff81bf55e1 cmd0646_9_tim_udma+0x1dacc rip 0xffffffff81aee3ba db_enter+0xa cs 0x8 rflags 0x206 rsp 0xffff8000211c75c0 ss 0x10 db_enter+0xa: popq %rbp ddb{0}> show proc PROC (syz-executor1) pid=498603 stat=sleep flags process=1010 proc=4002000 pri=50, usrpri=86, nice=20 forw=0x0, list=0xffff8000210a32d8,0xffff8000210a24d8 process=0xffff8000210cb308 user=0xffff8000211c2000, vmspace=0xffffff0069b34218 estcpu=36, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND *63822 498603 86285 65534 3 0x4003010 suspend syz-executor1 63822 24345 86285 65534 2 0x4081090 syz-executor1 39967 461309 45667 65534 2 0x10 syz-executor0 39967 291462 45667 65534 3 0x4000090 fsleep syz-executor0 39967 420929 45667 65534 2 0x4000010 syz-executor0 86285 461130 20612 65534 3 0x90 nanosleep syz-executor1 20612 199170 36653 0 3 0x82 wait syz-executor1 45667 329417 88634 65534 3 0x90 nanosleep syz-executor0 88634 443434 36653 0 3 0x82 wait syz-executor0 90785 434877 0 0 3 0x14200 bored sosplice 36653 336201 92455 0 3 0x82 thrsleep syz-fuzzer 36653 33367 92455 0 3 0x4000082 thrsleep syz-fuzzer 36653 465311 92455 0 3 0x4000082 thrsleep syz-fuzzer 36653 379459 92455 0 3 0x4000082 thrsleep syz-fuzzer 36653 105111 92455 0 3 0x4000082 thrsleep syz-fuzzer 36653 251422 92455 0 3 0x4000082 thrsleep syz-fuzzer 36653 69106 92455 0 3 0x4000082 thrsleep syz-fuzzer 36653 233969 92455 0 3 0x4000082 thrsleep syz-fuzzer 36653 351085 92455 0 3 0x4000082 kqread syz-fuzzer 36653 276996 92455 0 3 0x4000082 thrsleep syz-fuzzer 92455 13361 46670 0 3 0x10008a pause ksh 46670 251265 49857 0 3 0x92 select sshd 71266 311480 1 0 3 0x100083 ttyin getty 49857 384744 1 0 3 0x80 select sshd 17641 300400 96395 73 3 0x100090 kqread syslogd 96395 227701 1 0 3 0x100082 netio syslogd 16259 310582 1 77 3 0x100090 poll dhclient 24510 437733 1 0 3 0x80 poll dhclient 92517 271065 0 0 2 0x14200 zerothread 38776 298956 0 0 3 0x14200 aiodoned aiodoned 76809 475995 0 0 3 0x14200 syncer update 82778 198543 0 0 3 0x14200 cleaner cleaner 90981 318693 0 0 3 0x14200 reaper reaper 41656 50500 0 0 3 0x14200 pgdaemon pagedaemon 67219 214703 0 0 3 0x14200 bored crynlk 87657 75590 0 0 3 0x14200 bored crypto 35265 333504 0 0 3 0x40014200 acpi0 acpi0 84665 215903 0 0 3 0x40014200 idle1 45872 406310 0 0 3 0x14200 bored softnet 67900 189485 0 0 3 0x14200 bored systqmp 31983 51030 0 0 3 0x14200 bored systq 38117 117943 0 0 3 0x40014200 bored softclock 60041 520844 0 0 3 0x40014200 idle0 1 379869 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper