uvm_fault(0xfffffd800b063000, 0x0, 0, 1) -> e fatal page fault in supervisor mode trap type 6 code 0 rip ffffffff830e8e28 cs 8 rflags 10207 cr2 0 cpl 0 rsp ffff80003dc733a0 gsbase 0xffff8000299ddff0 kgsbase 0x0 panic: trap type 6, code=0, pc=ffffffff830e8e28 Starting stack trace... panic(ffffffff833e1f9e) at panic+0x1d0 sys/kern/subr_prf.c:229 kerntrap(ffff80003dc732f0) at kerntrap+0x30b alltraps_kern_meltdown() at alltraps_kern_meltdown+0x7b dt_ioctl_record_stop(ffff800001592000) at dt_ioctl_record_stop+0x108 sys/dev/dt/dt_dev.c:593 dtclose(11e5f,81,2000,ffff8000fffe3a18) at dtclose+0x109 dt_pcb_purge sys/dev/dt/dt_dev.c:-1 [inline] dtclose(11e5f,81,2000,ffff8000fffe3a18) at dtclose+0x109 sys/dev/dt/dt_dev.c:239 spec_close(ffff80003dc734a0) at spec_close+0x466 sys/kern/spec_vnops.c:-1 VOP_CLOSE(fffffd805cf63638,81,fffffd80097fd208,ffff8000fffe3a18) at VOP_CLOSE+0x132 sys/kern/vfs_vops.c:156 vn_closefile(fffffd805c8de7b0,ffff8000fffe3a18) at vn_closefile+0x12b vn_close sys/kern/vfs_vnops.c:292 [inline] vn_closefile(fffffd805c8de7b0,ffff8000fffe3a18) at vn_closefile+0x12b sys/kern/vfs_vnops.c:615 fdrop(fffffd805c8de7b0,ffff8000fffe3a18) at fdrop+0x121 sys/kern/kern_descrip.c:1280 closef(fffffd805c8de7b0,ffff8000fffe3a18) at closef+0x192 sys/kern/kern_descrip.c:1264 fdfree(ffff8000fffe3a18) at fdfree+0x116 sys/kern/kern_descrip.c:1195 exit1(ffff8000fffe3a18,0,0,1) at exit1+0x576 sys/kern/kern_exit.c:215 sys_exit(ffff8000fffe3a18,ffff80003dc73810,ffff80003dc73760) at sys_exit+0x1a sys/kern/kern_exit.c:-1 syscall(ffff80003dc73810) at syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80003dc73810) at syscall+0xb17 sys/arch/amd64/amd64/trap.c:775 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x753515f468c0, count: 242 End of stack trace. WARNING: SPL NOT LOWERED ON SYSCALL 91 1408950088 EXIT 0 4 Stopped at savectx+0xae: movl $0,%gs:0x688 TID PID UID PRFLAGS PFLAGS CPU COMMAND *450895 18824 0 0 0 1 syz-executor 81155 8689 0 0x2 0x1 0 syz-executor savectx() at savectx+0xae end of kernel end trace frame: 0x7d1153fadf30, 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 *cpu1: uvm_fault(0xfffffd800b063000, 0x0, 0, 1) -> e ddb{1}> trace savectx() at savectx+0xae end of kernel end trace frame: 0x7d1153fadf30, count: -1 ddb{1}> show registers rdi 0 rsi 0 rbp 0xffff80003c40b650 rbx 0 rdx 0 rcx 0xffff80002a287a08 rax 0x3b r8 0xffff80003c40b580 r9 0x1 r10 0xf4ae05dceb290647 r11 0x199a37942efb3ff3 r12 0 r13 0 r14 0xffff80002a287a08 r15 0 rip 0xffffffff826863ee savectx+0xae cs 0x8 rflags 0x46 rsp 0xffff80003c40b5d0 ss 0x10 savectx+0xae: movl $0,%gs:0x688 ddb{1}> show proc PROC (syz-executor) tid=450895 pid=18824 tcnt=3 stat=onproc flags process=0 proc=0 runpri=32, usrpri=84, slppri=32, nice=20 wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0 forw=0xffffffffffffffff, list=0xffff8000fffe9a10,0xffff8000fffe2038 process=0xffff80003ea9f520 user=0xffff80003c406000, vmspace=0xfffffd806c49a7b8 estcpu=34, cpticks=8, pctcpu=0.8, user=6, sys=2, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 36075 211338 28244 0 2 0 syz-executor 95432 454537 97914 0 2 0 syz-executor 95432 508977 97914 0 3 0x4000080 fsleep syz-executor 95432 388638 97914 0 3 0x4000080 fsleep syz-executor *18824 450895 8689 0 7 0 syz-executor 18824 125317 8689 0 3 0x4000080 netcon syz-executor 18824 4729 8689 0 3 0x4000080 fsleep syz-executor 28244 135325 5108 0 2 0x3 syz-executor 27430 499560 0 0 3 0x14200 acct acct 97914 100902 5108 0 2 0x3 syz-executor 53328 371799 5108 0 2 0x2 syz-executor 66798 445326 5108 0 3 0x82 wait syz-executor 84380 315018 5108 0 2 0x3 syz-executor 8689 81155 5108 0 7 0x3 syz-executor 95341 366408 54796 0 3 0x100082 sbwait arp 54796 287619 1 0 3 0x10008a sigsusp sh 76062 92962 5108 0 2 0x2 syz-executor 65202 175197 5108 0 2 0x2 syz-executor 5108 247302 78183 0 3 0x82 kqread syz-executor 78183 57162 79980 0 3 0x10008a sigsusp ksh 79980 419195 14164 0 3 0x98 kqread sshd-session 14164 215056 7561 0 3 0x92 kqread sshd-session 48473 105057 1 0 3 0x100083 ttyopn getty 7561 204 1 0 3 0x88 kqread sshd 97643 157722 30998 74 3 0x1100092 bpf pflogd 30998 222689 1 0 3 0x80 sbwait pflogd 65544 315021 26247 73 3 0x1100090 kqread syslogd 26247 485800 1 0 3 0x100082 sbwait syslogd 14830 465498 1 0 3 0x100080 kqread resolvd 16304 106643 68568 77 3 0x100092 kqread dhcpleased 34751 335623 68568 77 3 0x100092 kqread dhcpleased 68568 514905 1 0 3 0x80 kqread dhcpleased 42893 454992 0 0 3 0x14200 bored smr 20203 121359 0 0 2 0x14200 zerothread 3675 95943 0 0 3 0x14200 aiodoned aiodoned 78905 2098 0 0 3 0x14200 syncer update 76828 444512 0 0 3 0x14200 cleaner cleaner 68774 2877 0 0 3 0x14200 reaper reaper 87816 359147 0 0 3 0x14200 pgdaemon pagedaemon 5798 208838 0 0 3 0x14200 bored viomb 9966 375637 0 0 3 0x40014200 acpi0 acpi0 72092 210450 0 0 3 0x40014200 idle1 77277 365249 0 0 3 0x14200 bored softnet1 89089 433690 0 0 3 0x14200 netlock softnet0 14705 197729 0 0 2 0x40014200 systqmp 47158 478508 0 0 3 0x14200 bored systq 78502 84817 0 0 3 0x14200 netlock softclockmp 82139 519306 0 0 3 0x40014200 tmoslp softclock 94350 82221 0 0 3 0x40014200 idle0 1 245100 0 0 3 0x80082 wait init 0 0 -1 0 3 0x10010200 scheduler swapper ddb{1}> show all locks Process 53328 (syz-executor) thread 0xffff8000fffe87e8 (371799) exclusive rwlock vmmaplk r = 0 (0xfffffd800b0634d0) #0 witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline] #0 witness_lock+0x5f1 sys/kern/subr_witness.c:1160 #1 rw_do_enter_write+0x419 sys/kern/kern_rwlock.c:320 #2 vm_map_lock_ln+0x12e sys/uvm/uvm_map.c:5165 #3 uvmspace_fork+0x12b sys/uvm/uvm_map.c:3746 #4 process_new+0x577 sys/kern/kern_fork.c:281 #5 fork1+0x3f6 sys/kern/kern_fork.c:-1 #6 syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline] #6 syscall+0xb17 sys/arch/amd64/amd64/trap.c:775 #7 Xsyscall+0x128 exclusive rwlock vmmaplk r = 0 (0xfffffd806c287120) #0 witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline] #0 witness_lock+0x5f1 sys/kern/subr_witness.c:1160 #1 rw_do_enter_write+0x419 sys/kern/kern_rwlock.c:320 #2 vm_map_lock_ln+0x12e sys/uvm/uvm_map.c:5165 #3 uvmspace_fork+0x44 sys/uvm/uvm_map.c:3737 #4 process_new+0x577 sys/kern/kern_fork.c:281 #5 fork1+0x3f6 sys/kern/kern_fork.c:-1 #6 syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline] #6 syscall+0xb17 sys/arch/amd64/amd64/trap.c:775 #7 Xsyscall+0x128 Process 76062 (syz-executor) thread 0xffff80002a287240 (92962) exclusive rwlock fdlock r = 0 (0xffff80002a26b2f8) #0 witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline] #0 witness_lock+0x5f1 sys/kern/subr_witness.c:1160 #1 rw_do_enter_write+0x419 sys/kern/kern_rwlock.c:320 #2 fdcopy+0x1a2 sys/kern/kern_descrip.c:1111 #3 process_new+0x4fc sys/kern/kern_fork.c:276 #4 fork1+0x3f6 sys/kern/kern_fork.c:-1 #5 syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline] #5 syscall+0xb17 sys/arch/amd64/amd64/trap.c:775 #6 Xsyscall+0x128 Process 65202 (syz-executor) thread 0xffff80002a286d10 (175197) exclusive rwlock fdlock r = 0 (0xffff80002a26a068) #0 witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline] #0 witness_lock+0x5f1 sys/kern/subr_witness.c:1160 #1 rw_do_enter_write+0x419 sys/kern/kern_rwlock.c:320 #2 fdcopy+0x1a2 sys/kern/kern_descrip.c:1111 #3 process_new+0x4fc sys/kern/kern_fork.c:276 #4 fork1+0x3f6 sys/kern/kern_fork.c:-1 #5 syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline] #5 syscall+0xb17 sys/arch/amd64/amd64/trap.c:775 #6 Xsyscall+0x128 ddb{1}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 11114 12185K 12603K 166960K 16288 0 pcb 17 16K 18K 166960K 572 0 rtable 252 12K 13K 166960K 736 0 pf 37 18K 22K 166960K 251 0 ifaddr 43 8K 8K 166960K 166 0 ifgroup 55 2K 2K 166960K 307 0 sysctl 4 1K 9K 166960K 18 0 counters 70 37K 38K 166960K 302 0 ioctlops 0 0K 4K 166960K 1921 0 iov 0 0K 24K 166960K 212 0 mount 1 1K 1K 166960K 1 0 log 0 0K 0K 166960K 4 0 vnodes 1465 92K 93K 166960K 3784 0 UFS quota 1 32K 32K 166960K 1 0 UFS mount 5 36K 36K 166960K 5 0 shm 2 1K 5K 166960K 41 0 VM map 2 1K 1K 166960K 2 0 sem 30 1K 1K 166960K 84 0 dirhash 12 2K 2K 166960K 60 0 ACPI 1692 195K 286K 166960K 12470 0 file desc 18 65K 240K 166960K 2661 0 sigio 0 0K 0K 166960K 102 0 proc 72 115K 164K 166960K 929 0 subproc 81 5K 5K 166960K 126 0 NFS srvsock 1 0K 0K 166960K 1 0 NFS daemon 1 16K 16K 166960K 1 0 ip_moptions 0 0K 0K 166960K 360 0 in_multi 99 7K 7K 166960K 250 0 ether_multi 1 0K 0K 166960K 24 0 mrt 1 0K 0K 166960K 33 0 ISOFS mount 1 32K 32K 166960K 1 0 MSDOSFS mount 1 16K 16K 166960K 1 0 ttys 247 1102K 1102K 166960K 247 0 exec 0 0K 1K 166960K 845 0 fusefs mount 1 32K 32K 166960K 1 0 pfkey data 0 0K 0K 166960K 6 0 tdb 3 0K 0K 166960K 3 0 VM swap 8 62K 64K 166960K 10 0 UVM amap 245 165K 193K 166960K 26897 0 UVM aobj 22 14K 14K 166960K 23 0 pinsyscall 46 92K 108K 166960K 3938 0 memdesc 1 4K 4K 166960K 1 0 crypto data 1 1K 1K 166960K 1 0 ip6_options 0 0K 1K 166960K 263 0 NDP 12 0K 1K 166960K 120 0 temp 84 8680K 8808K 166960K 152577 0 kqueue 13 20K 33K 166960K 510 0 SYN cache 2 8K 16K 166960K 3 0 ddb{1}> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle plcache 128 26 0 0 1 0 1 1 0 8 0 rtpcb 120 254 0 250 3 0 3 3 0 8 2 rtentry 176 230 0 128 5 0 5 5 0 8 0 unpcb 144 1614 0 1595 12 11 1 4 0 8 0 syncache 336 14 0 14 9 8 1 1 0 8 1 tcpqe 32 7 0 7 5 5 0 1 0 8 0 tcpcb 736 1017 0 1011 28 21 7 7 0 8 6 arp 136 43 0 26 1 0 1 1 0 8 0 inpcb 328 3166 0 3157 50 40 10 15 0 8 8 nd6 152 43 0 17 2 0 2 2 0 8 0 pkpcb 40 12 0 12 6 5 1 1 0 8 1 kcovpl 48 14 0 5 1 0 1 1 0 8 0 mppekey 1024 1 0 1 1 1 0 1 0 8 0 ppxss 1192 83 0 83 5 4 1 1 0 8 1 pppxif 1504 12 0 12 6 6 0 1 0 8 0 pfstscr 40 1 0 1 1 1 0 1 0 8 0 pffrag 232 32 0 18 1 0 1 1 0 482 0 pffrnode 88 28 0 15 1 0 1 1 0 8 0 pffrent 40 90 0 76 1 0 1 1 0 8 0 pfosfp 40 1428 0 1005 5 0 5 5 0 8 0 pfosfpen 112 1428 0 714 21 0 21 21 0 8 0 pfanchor 1288 1 0 1 1 1 0 1 0 8 0 pfstitem 24 131 0 84 1 0 1 1 0 8 0 pfstkey 128 133 0 87 2 0 2 2 0 8 0 pfstate 448 130 0 85 6 0 6 6 0 8 0 pfrule 1344 26 0 21 2 1 1 2 0 8 0 rttmr 136 7 0 7 5 4 1 1 0 8 1 art_heap8 4096 3 0 1 3 1 2 3 0 8 0 art_heap4 256 938 0 480 40 10 30 31 0 8 0 art_table 40 941 0 481 6 1 5 6 0 8 0 art_node 32 227 0 135 1 0 1 1 0 8 0 sysvmsgpl 40 19 0 14 1 0 1 1 0 8 0 semupl 112 6 0 6 5 5 0 1 0 8 0 semapl 112 77 0 49 1 0 1 1 0 8 0 shmpl 112 14 0 1 1 0 1 1 0 8 0 dirhash 1024 50 0 33 3 0 3 3 0 8 0 dino2pl 256 6308 0 4792 97 1 96 96 0 8 0 ffsino 296 6308 0 4792 118 0 118 118 0 8 0 nchpl 144 9949 0 8232 65 0 65 65 0 8 1 rtmask 32 11 0 11 7 7 0 1 0 8 0 vnodes 216 5927 0 0 330 0 330 330 0 8 0 namei 1024 34978 0 34978 7 6 1 2 0 8 1 percpumem 16 166 0 116 1 0 1 1 0 8 0 vcpupl 3968 6 0 0 1 0 1 1 0 8 0 vmpool 848 6 0 0 1 0 1 1 0 8 0 kstatmem 264 186 0 160 6 4 2 3 0 8 0 scsiplug 72 7 0 7 6 5 1 1 0 8 1 scxspl 216 65249 0 65249 10 9 1 4 1 8 1 plimitpl 152 648 0 628 1 0 1 1 0 8 0 sigapl 424 2953 0 2904 9 2 7 7 0 8 0 knotepl 120 603 0 0 18 0 18 18 0 8 0 kqueuepl 224 1032 0 1023 16 13 3 5 0 8 2 pipepl 344 491 0 461 17 13 4 9 0 8 0 fdescpl 528 2917 0 2883 3 0 3 3 0 8 0 filepl 160 19335 0 19092 50 34 16 20 0 8 4 lockfpl 104 1363 0 1359 3 2 1 2 0 8 0 lockfspl 48 581 0 577 1 0 1 1 0 8 0 sessionpl 144 35 0 26 1 0 1 1 0 8 0 pgrppl 48 70 0 52 1 0 1 1 0 8 0 ucredpl 104 2598 0 2585 1 0 1 1 0 8 0 zombiepl 144 4211 0 4209 3 2 1 1 0 8 0 processpl 1232 2955 0 2904 7 2 5 5 0 8 0 procpl 664 7599 0 7544 8 2 6 7 0 8 0 sosppl 176 20 0 20 9 8 1 1 0 8 1 sockpl 752 5105 0 5072 70 57 13 20 0 8 8 mcl64k 65536 24 0 0 3 0 3 3 0 8 0 mcl16k 16384 5 0 0 1 0 1 1 0 8 0 mcl12k 12288 1 0 0 1 0 1 1 0 8 0 mcl9k 9216 2 0 0 1 0 1 1 0 8 0 mcl8k 8192 5 0 0 1 0 1 1 0 8 0 mcl4k 4096 117 0 0 15 0 15 15 0 8 0 mcl2k2 2112 1 0 0 1 0 1 1 0 8 0 mcl2k 2048 52 0 0 6 0 6 6 0 8 0 mtagpl 96 130 0 0 4 0 4 4 0 8 0 mbufpl 256 1739 0 0 109 0 109 109 0 8 0 bufpl 280 25755 0 19619 439 0 439 439 0 8 0 anonpl 32 11722 0 0 95 0 95 95 0 246 0 amapchunkpl 152 94592 0 94129 75 43 32 39 0 158 11 amappl16 200 8935 0 8901 88 74 14 27 0 8 8 amappl15 192 7 0 7 1 1 0 1 0 8 0 amappl14 184 11 0 11 1 1 0 1 0 8 0 amappl13 176 493 0 491 1 0 1 1 0 8 0 amappl12 168 3324 0 3281 3 0 3 3 0 8 0 amappl11 160 6 0 6 2 2 0 1 0 8 0 amappl10 152 53 0 39 1 0 1 1 0 8 0 amappl9 144 246 0 246 2 2 0 1 0 8 0 amappl8 136 73 0 70 1 0 1 1 0 8 0 amappl7 128 110 0 109 1 0 1 1 0 8 0 amappl6 120 358 0 342 1 0 1 1 0 8 0 amappl5 112 152 0 140 1 0 1 1 0 8 0 amappl4 104 487 0 457 1 0 1 1 0 8 0 amappl3 96 18673 0 18571 4 0 4 4 0 8 0 amappl2 88 643 0 580 2 0 2 2 0 8 0 amappl1 80 21707 0 21086 15 0 15 15 0 8 0 amappl 88 25602 0 25442 5 0 5 5 0 92 0 uvmvnodes 80 209 0 0 5 0 5 5 0 8 0 dma65536 65536 1 0 1 1 1 0 1 0 8 0 dma4096 4096 2 0 2 2 2 0 1 0 8 0 dma1024 1024 1 0 0 1 0 1 1 0 8 0 dma256 256 7 0 7 2 2 0 1 0 8 0 dma128 128 254 0 254 2 2 0 1 0 8 0 dma64 64 7 0 7 2 2 0 1 0 8 0 dma32 32 7 0 7 1 1 0 1 0 8 0 dma16 16 18 0 17 1 0 1 1 0 8 0 aobjpl 72 22 0 1 1 0 1 1 0 8 0 uaddrrnd 24 2915 0 2883 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 2915 0 2883 1 0 1 1 0 8 0 vmmpekpl 168 25364 0 25310 3 0 3 3 0 8 0 vmmpepl 168 191235 0 189321 154 50 104 109 0 357 6 vmsppl 488 2914 0 2883 5 0 5 5 0 8 0 rwobjpl 80 50616 0 49413 41 9 32 34 0 8 0 pdppl 4096 5849 0 5772 127 46 81 85 0 8 4 pvpl 32 20899 0 0 168 0 168 168 0 265 0 pmappl 256 2920 0 2883 3 0 3 3 0 8 0 extentpl 40 45 0 27 1 0 1 1 0 8 0 phpool 112 465 0 99 11 0 11 11 0 8 0 ddb{1}> machine ddbcpu 0 Stopped at x86_ipi_db+0x27: addq $0x8,%rsp x86_ipi_db(ffffffff8385eff0) at x86_ipi_db+0x27 sys/arch/amd64/amd64/db_interface.c:394 x86_ipi_handler() at x86_ipi_handler+0xd9 sys/arch/amd64/amd64/ipi.c:106 Xresume_lapic_ipi() at Xresume_lapic_ipi+0x27 __sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0x3d sys/dev/kcov.c:159 softintr_dispatch(0) at softintr_dispatch+0x125 sys/kern/kern_softintr.c:83 dosoftint(0) at dosoftint+0x54 sys/arch/amd64/amd64/intr.c:862 Xsoftclock() at Xsoftclock+0x27 __mp_lock(ffffffff838e8a40) at __mp_lock+0x199 __mp_lock_spin sys/kern/kern_lock.c:142 [inline] __mp_lock(ffffffff838e8a40) at __mp_lock+0x199 sys/kern/kern_lock.c:173 ktrsyscall(ffff8000fffe8550,5b,10,ffff80003c439d50) at ktrsyscall+0x2c7 ktrwrite sys/kern/kern_ktrace.c:-1 [inline] ktrsyscall(ffff8000fffe8550,5b,10,ffff80003c439d50) at ktrsyscall+0x2c7 sys/kern/kern_ktrace.c:183 syscall(ffff80003c439d50) at syscall+0x304 mi_syscall sys/sys/syscall_mi.h:154 [inline] syscall(ffff80003c439d50) at syscall+0x304 sys/arch/amd64/amd64/trap.c:775 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7d1153fae0b0, count: 4 ddb{0}> trace x86_ipi_db(ffffffff8385eff0) at x86_ipi_db+0x27 sys/arch/amd64/amd64/db_interface.c:394 x86_ipi_handler() at x86_ipi_handler+0xd9 sys/arch/amd64/amd64/ipi.c:106 Xresume_lapic_ipi() at Xresume_lapic_ipi+0x27 __sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0x3d sys/dev/kcov.c:159 softintr_dispatch(0) at softintr_dispatch+0x125 sys/kern/kern_softintr.c:83 dosoftint(0) at dosoftint+0x54 sys/arch/amd64/amd64/intr.c:862 Xsoftclock() at Xsoftclock+0x27 __mp_lock(ffffffff838e8a40) at __mp_lock+0x199 __mp_lock_spin sys/kern/kern_lock.c:142 [inline] __mp_lock(ffffffff838e8a40) at __mp_lock+0x199 sys/kern/kern_lock.c:173 ktrsyscall(ffff8000fffe8550,5b,10,ffff80003c439d50) at ktrsyscall+0x2c7 ktrwrite sys/kern/kern_ktrace.c:-1 [inline] ktrsyscall(ffff8000fffe8550,5b,10,ffff80003c439d50) at ktrsyscall+0x2c7 sys/kern/kern_ktrace.c:183 syscall(ffff80003c439d50) at syscall+0x304 mi_syscall sys/sys/syscall_mi.h:154 [inline] syscall(ffff80003c439d50) at syscall+0x304 sys/arch/amd64/amd64/trap.c:775 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7d1153fae0b0, count: -11 ddb{0}> machine ddbcpu 1 Stopped at savectx+0xae: movl $0,%gs:0x688 savectx() at savectx+0xae end of kernel end trace frame: 0x7d1153fadf30, count: 14 ddb{1}> trace savectx() at savectx+0xae end of kernel end trace frame: 0x7d1153fadf30, count: -1