login: witness: panic: kernel diagnostic assertion "_kernel_lock_held()" failed: file "/syzkaller/managers/multicore/kernel/sys/kern/kern_event.c", line 1076 Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND 202908 14321 0 0 0 1 syz-executor.0 * 86986 14321 0 0 0x4000000 0 syz-executor.0 db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic() at panic+0x15c sys/kern/subr_prf.c:208 __assert(ffffffff81f8e31d,ffffffff81f86db9,434,ffffffff81f98402) at __assert+0x2e sys/kern/subr_prf.c:155 knote_enqueue(fffffd806e99ec40) at knote_enqueue+0x216 sys/kern/kern_event.c:1076 knote(ffffffff82338c38,1000000) at knote+0xbd sys/kern/kern_event.c:957 selwakeup(ffffffff82338c38) at selwakeup+0x3b sys/kern/sys_generic.c:795 logwakeup() at logwakeup+0x3b sys/kern/subr_log.c:310 printf(ffffffff81f6bd50) at printf+0x9f sys/kern/subr_prf.c:519 witness_warn(2,0,ffffffff81f94722) at witness_warn+0x211 sys/kern/subr_witness.c:1416 userret(ffff800020b85c30) at userret+0x32a sys/kern/kern_sig.c:1902 syscall(ffff800020c13370) at syscall+0x614 mi_syscall_return sys/sys/syscall_mi.h:122 [inline] syscall(ffff800020c13370) at syscall+0x614 sys/arch/amd64/amd64/trap.c:596 Xsyscall(6,0,fffffffffffffef6,0,1,d68f9f821a0) at Xsyscall+0x128 end of kernel end trace frame: 0x78, count: 3 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}> set $maxwidth = 0 ddb{0}> show panic kernel diagnostic assertion "_kernel_lock_held()" failed: file "/syzkaller/managers/multicore/kernel/sys/kern/kern_event.c", line 1076 ddb{0}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic() at panic+0x15c sys/kern/subr_prf.c:208 __assert(ffffffff81f8e31d,ffffffff81f86db9,434,ffffffff81f98402) at __assert+0x2e sys/kern/subr_prf.c:155 knote_enqueue(fffffd806e99ec40) at knote_enqueue+0x216 sys/kern/kern_event.c:1076 knote(ffffffff82338c38,1000000) at knote+0xbd sys/kern/kern_event.c:957 selwakeup(ffffffff82338c38) at selwakeup+0x3b sys/kern/sys_generic.c:795 logwakeup() at logwakeup+0x3b sys/kern/subr_log.c:310 printf(ffffffff81f6bd50) at printf+0x9f sys/kern/subr_prf.c:519 witness_warn(2,0,ffffffff81f94722) at witness_warn+0x211 sys/kern/subr_witness.c:1416 userret(ffff800020b85c30) at userret+0x32a sys/kern/kern_sig.c:1902 syscall(ffff800020c13370) at syscall+0x614 mi_syscall_return sys/sys/syscall_mi.h:122 [inline] syscall(ffff800020c13370) at syscall+0x614 sys/arch/amd64/amd64/trap.c:596 Xsyscall(6,0,fffffffffffffef6,0,1,d68f9f821a0) at Xsyscall+0x128 end of kernel end trace frame: 0x78, count: -12 ddb{0}> show registers rdi 0 rsi 0x1 rbp 0xffff800020c12ee0 rbx 0xffff800020c12f90 rdx 0x8b rcx 0x2 rax 0x1 r8 0xffffffff8140baf3 kprintf+0x173 r9 0x1 r10 0x47855f0b0ecbd4ac r11 0x965d393a489a3e8a r12 0x3000000008 r13 0xffff800020c12ef0 r14 0x100 r15 0x1 rip 0xffffffff814647a8 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800020c12ed0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{0}> show proc PROC (syz-executor.0) pid=86986 stat=onproc flags process=0 proc=4000000 pri=32, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffff800020b159d0,0xffffffff82355ec8 process=0xffff800020b8d3c8 user=0xffff800020c0e000, vmspace=0xfffffd807effe000 estcpu=36, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 14321 202908 56857 0 7 0 syz-executor.0 14321 408636 56857 0 2 0x4000000 syz-executor.0 14321 206648 56857 0 3 0x4000080 fsleep syz-executor.0 *14321 86986 56857 0 7 0x4000000 syz-executor.0 56857 266063 26686 0 3 0x82 nanosleep syz-executor.0 26686 457077 45542 0 3 0x82 thrsleep syz-execprog 26686 434506 45542 0 3 0x4000082 thrsleep syz-execprog 26686 75657 45542 0 3 0x4000082 thrsleep syz-execprog 26686 488498 45542 0 3 0x4000082 thrsleep syz-execprog 26686 360720 45542 0 3 0x4000082 thrsleep syz-execprog 26686 167281 45542 0 3 0x4000082 kqread syz-execprog 26686 182200 45542 0 3 0x4000082 thrsleep syz-execprog 45542 422297 93317 0 3 0x10008a pause ksh 93317 352243 97636 0 3 0x92 select sshd 33057 509657 1 0 3 0x100083 ttyin getty 97636 444364 1 0 3 0x80 select sshd 1040 301252 21182 74 3 0x100092 bpf pflogd 21182 510073 1 0 3 0x80 netio pflogd 3552 350631 5771 73 3 0x100090 kqread syslogd 5771 308847 1 0 3 0x100082 netio syslogd 33937 204033 1 77 3 0x100090 poll dhclient 87400 50168 1 0 3 0x80 poll dhclient 99468 372216 0 0 3 0x14200 pgzero zerothread 17093 77088 0 0 3 0x14200 aiodoned aiodoned 84904 350478 0 0 3 0x14200 syncer update 2617 31525 0 0 3 0x14200 cleaner cleaner 44893 73563 0 0 3 0x14200 reaper reaper 36295 439236 0 0 3 0x14200 pgdaemon pagedaemon 6197 324030 0 0 3 0x14200 bored crynlk 65412 397660 0 0 3 0x14200 bored crypto 70015 89141 0 0 3 0x40014200 acpi0 acpi0 37662 393446 0 0 3 0x40014200 idle1 48209 306617 0 0 3 0x14200 bored softnet 74389 97838 0 0 3 0x14200 bored systqmp 94054 482683 0 0 3 0x14200 bored systq 75013 434881 0 0 3 0x40014200 bored softclock 49689 516549 0 0 3 0x40014200 idle0 44827 389884 0 0 3 0x14200 bored smr 1 427473 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{0}>