EXIkernel: Stopped at savectx+0xae: movl $0,%gs:0x688 TID PID UID PRFLAGS PFLAGS CPU COMMAND 349972 33723 0 0 0x4000000 0K syz-executor *267002 3070 0 0x2 0 1 syz-executor savectx() at savectx+0xae end of kernel end trace frame: 0x701b13dbf560, count: 14 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}> set $maxwidth = 0 ddb{1}> show panic *cpu0: uvm_fault(0xfffffd806c5b35d8, 0x98, 0, 1) -> e ddb{1}> trace savectx() at savectx+0xae end of kernel end trace frame: 0x701b13dbf560, count: -1 ddb{1}> show registers rdi 0 rsi 0 rbp 0xffff80002a2a41e0 rbx 0 rdx 0 rcx 0xffff80002a232010 rax 0x34 r8 0xffff80002a2a4110 r9 0xffff80002a2a3f7c r10 0xa5c05b3c90aa857f r11 0x288c7b22379a4e25 r12 0 r13 0 r14 0xffff80002a232010 r15 0 rip 0xffffffff81d973ee savectx+0xae cs 0x8 rflags 0x46 rsp 0xffff80002a2a4160 ss 0x10 savectx+0xae: movl $0,%gs:0x688 ddb{1}> show proc PROC (syz-executor) tid=267002 pid=3070 tcnt=1 stat=onproc flags process=2 proc=0 runpri=16, usrpri=59, slppri=16, nice=20 wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0 forw=0xffffffffffffffff, list=0xffff80002a233a00,0xffff8000ffffc7e0 process=0xffff8000ffff1820 user=0xffff80002a29f000, vmspace=0xfffffd806e830b80 estcpu=9, cpticks=60, pctcpu=0.40, user=1, sys=57, intr=2 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 33723 391237 15051 0 2 0 syz-executor 33723 349972 15051 0 7 0x4000000 syz-executor 95042 234563 94944 0 2 0 syz-executor 95042 220997 94944 0 3 0x4000080 fsleep syz-executor 95042 211491 94944 0 3 0x4000080 kqread syz-executor 80823 137456 50142 0 3 0x80 nanoslp syz-executor 80823 513284 50142 0 3 0x4000080 ttyin syz-executor 80823 365922 50142 0 3 0x4000080 fsleep syz-executor 12456 142861 51050 60929 3 0x90 nanoslp syz-executor 12456 277033 51050 60929 3 0x4000090 lockf syz-executor 12456 229305 51050 60929 3 0x4000090 lockf syz-executor 12456 460703 51050 60929 3 0x4000090 fsleep syz-executor 92668 406096 72295 0 3 0x80 nanoslp syz-executor 92668 123114 72295 0 3 0x4000080 kqsel syz-executor 92668 502602 72295 0 3 0x4000080 fsleep syz-executor 58910 62083 93887 0 3 0x80 nanoslp syz-executor 58910 335303 93887 0 3 0x4000080 bell syz-executor 58910 54148 93887 0 3 0x4000080 fsleep syz-executor 58910 489727 93887 0 3 0x4000080 fsleep syz-executor 71343 421437 58880 0 2 0 syz-executor 71343 74332 58880 0 3 0x4000080 pipewr syz-executor 71343 18923 58880 0 3 0x4000080 fsleep syz-executor 71343 301469 58880 0 3 0x4000080 fsleep syz-executor 65808 360408 1 0 3 0x82 nanoslp getty 66263 147875 69831 0 3 0x100082 sbwait arp 69831 314198 43059 0 3 0x10008a sigsusp sh 50142 181945 3070 0 3 0x82 nanoslp syz-executor 15051 83015 3070 0 3 0x82 nanoslp syz-executor 43059 253419 3070 0 3 0x82 wait syz-executor 72295 345959 3070 0 3 0x82 nanoslp syz-executor 93887 184784 3070 0 3 0x82 nanoslp syz-executor 94944 431640 3070 0 3 0x82 nanoslp syz-executor 51050 422409 3070 0 3 0x82 nanoslp syz-executor 58880 443041 3070 0 3 0x82 nanoslp syz-executor * 3070 267002 1 0 7 0x2 syz-executor 6778 125315 1 0 3 0x1000008a kqread sshd 2085 495265 67116 74 3 0x1100092 bpf pflogd 67116 186629 1 0 3 0x80 sbwait pflogd 15968 236959 8025 73 3 0x1100090 kqread syslogd 8025 138837 1 0 3 0x100082 sbwait syslogd 90498 428246 1 0 3 0x100080 kqread resolvd 66617 168565 26619 77 3 0x100092 kqread dhcpleased 11379 324614 26619 77 3 0x100092 kqread dhcpleased 26619 417900 1 0 3 0x80 kqread dhcpleased 17750 176648 0 0 3 0x14200 bored smr 91522 131492 0 0 2 0x14200 zerothread 95320 346990 0 0 3 0x14200 aiodoned aiodoned 34179 337416 0 0 3 0x14200 syncer update 29080 252692 0 0 3 0x14200 cleaner cleaner 79531 4673 0 0 3 0x14200 reaper reaper 78008 76137 0 0 3 0x14200 pgdaemon pagedaemon 61455 331517 0 0 3 0x14200 bored viomb 93368 379368 0 0 3 0x40014200 acpi0 acpi0 70342 351364 0 0 3 0x40014200 idle1 96980 465166 0 0 3 0x14200 bored softnet1 92576 81008 0 0 3 0x14200 bored softnet0 29673 89051 0 0 3 0x14200 bored systqmp 78044 251998 0 0 3 0x14200 bored systq 14272 199544 0 0 3 0x14200 tmoslp softclockmp 73560 122145 0 0 3 0x40014200 tmoslp softclock 19442 388892 0 0 3 0x40014200 idle0 1 172997 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{1}> show all locks CPU 1: exclusive mutex &kq->kq_lock r = 0 (0xfffffd8078342010) #0 witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline] #0 witness_lock+0x5f1 sys/kern/subr_witness.c:1160 #1 mtx_enter+0x4b4 sys/kern/kern_lock.c:487 #2 kqueue_register+0x1000 sys/kern/kern_event.c:1545 #3 pselregister+0x135 sys/kern/sys_generic.c:764 #4 dopselect+0x456 sys/kern/sys_generic.c:657 #5 sys_pselect+0x25a sys/kern/sys_generic.c:593 #6 syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline] #6 syscall+0xbd4 sys/arch/amd64/amd64/trap.c:783 #7 Xsyscall+0x128 Process 33723 (syz-executor) thread 0xffff800035bb2020 (349972) exclusive kernel_lock &kernel_lock r = 0 (0xffffffff83a6a700) #0 witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline] #0 witness_lock+0x5f1 sys/kern/subr_witness.c:1160 #1 syscall+0xaf4 mi_syscall sys/sys/syscall_mi.h:175 [inline] #1 syscall+0xaf4 sys/arch/amd64/amd64/trap.c:783 #2 Xsyscall+0x128 ddb{1}>