uvm_fault(0xfffffd8070eab018, 0x48, 0, 1) -> e fatal page fault in supervisor mode trap type 6 code 0 rip ffffffff825e0e05 cs 8 rflags 10246 cr2 48 cpl 0 rsp ffff80002a3e49e0 gsbase 0xffff8000299edff0 kgsbase 0x0 panic: trap type 6, code=0, pc=ffffffff825e0e05 Starting stack trace... panic(ffffffff833a0b15) at panic+0x1d0 sys/kern/subr_prf.c:229 kerntrap(ffff80002a3e4930) at kerntrap+0x30b alltraps_kern_meltdown() at alltraps_kern_meltdown+0x7b witness_checkorder(28,9,0) at witness_checkorder+0xb5 sys/kern/subr_witness.c:779 mtx_enter(18) at mtx_enter+0x4a sys/kern/kern_lock.c:260 clockintr_unbind(ffff80000148c030,1) at clockintr_unbind+0x56 sys/kern/kern_clockintr.c:375 dt_ioctl_record_stop(ffff800001471000) at dt_ioctl_record_stop+0xbc sys/dev/dt/dt_dev.c:582 dtclose(31e5f,81,2000,ffff80002a3f6fc8) at dtclose+0x109 dt_pcb_purge sys/dev/dt/dt_dev.c:-1 [inline] dtclose(31e5f,81,2000,ffff80002a3f6fc8) at dtclose+0x109 sys/dev/dt/dt_dev.c:232 spec_close(ffff80002a3e4c20) at spec_close+0x466 sys/kern/spec_vnops.c:-1 VOP_CLOSE(fffffd806b2522d8,81,fffffd80097fb548,ffff80002a3f6fc8) at VOP_CLOSE+0x132 sys/kern/vfs_vops.c:156 vn_closefile(fffffd806b2f43d0,ffff80002a3f6fc8) at vn_closefile+0x12b vn_close sys/kern/vfs_vnops.c:292 [inline] vn_closefile(fffffd806b2f43d0,ffff80002a3f6fc8) at vn_closefile+0x12b sys/kern/vfs_vnops.c:615 fdrop(fffffd806b2f43d0,ffff80002a3f6fc8) at fdrop+0x121 sys/kern/kern_descrip.c:1280 closef(fffffd806b2f43d0,ffff80002a3f6fc8) at closef+0x192 sys/kern/kern_descrip.c:1264 fdfree(ffff80002a3f6fc8) at fdfree+0x116 sys/kern/kern_descrip.c:1195 exit1(ffff80002a3f6fc8,0,0,1) at exit1+0x576 sys/kern/kern_exit.c:215 sys_exit(ffff80002a3f6fc8,ffff80002a3e4f90,ffff80002a3e4ee0) at sys_exit+0x1a sys/kern/kern_exit.c:-1 syscall(ffff80002a3e4f90) at syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80002a3e4f90) at syscall+0xb17 sys/arch/amd64/amd64/trap.c:746 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f40d91780b0, count: 239 End of stack trace. WARNING: SPL NOT LOWERED ON SYSCALL 91 -652771176 EXIT 0 4 Stopped at savectx+0xae: movl $0,%gs:0x688 TID PID UID PRFLAGS PFLAGS CPU COMMAND 450718 30470 0 0x1000 0x4080000 0K syz-executor *400544 14371 0 0x2 0 1 syz-executor savectx() at savectx+0xae end of kernel end trace frame: 0x7f40d9178080, 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}> set $lines = 0 ddb{1}> set $maxwidth = 0 ddb{1}> show panic *cpu1: uvm_fault(0xfffffd8070eab018, 0x48, 0, 1) -> e ddb{1}> trace savectx() at savectx+0xae end of kernel end trace frame: 0x7f40d9178080, count: -1 ddb{1}> show registers rdi 0 rsi 0 rbp 0xffff80002a3d9980 rbx 0 rdx 0 rcx 0xffff8000ffff34d0 rax 0x3b r8 0xffff80002a3d98b0 r9 0x1 r10 0xa21d736a894180ae r11 0xe3b7f9d285192873 r12 0 r13 0 r14 0xffff8000ffff34d0 r15 0 rip 0xffffffff813503ee savectx+0xae cs 0x8 rflags 0x46 rsp 0xffff80002a3d9900 ss 0 savectx+0xae: movl $0,%gs:0x688 ddb{1}> show proc PROC (syz-executor) tid=400544 pid=14371 tcnt=1 stat=onproc flags process=2 proc=0 runpri=50, usrpri=50, slppri=32, nice=20 wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0 forw=0xffffffffffffffff, list=0xffff8000ffff3a00,0xffff80002a2e4fc0 process=0xffff80002a2c39d8 user=0xffff80002a3d4000, vmspace=0xfffffd800b027000 estcpu=36, cpticks=45, pctcpu=0.13, user=0, sys=43, intr=2 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 22740 202172 88342 0 2 0 syz-executor 22740 113309 88342 0 3 0x4000080 fsleep syz-executor 22740 282685 88342 0 3 0x4000080 lockf syz-executor 22740 11673 88342 0 3 0x4000080 fsleep syz-executor 72515 32478 58524 60929 2 0xc90 syz-executor 72515 497201 58524 60929 3 0x4000090 msgwait syz-executor 72515 325312 58524 60929 3 0x4000090 fsleep syz-executor 45569 287189 17313 0 2 0xc80 syz-executor 45569 410955 17313 0 3 0x4000080 netcon syz-executor 45569 240035 17313 0 3 0x4000080 fsleep syz-executor 30826 237616 6815 0 2 0 syz-executor 30826 235987 6815 0 3 0x4000080 sbwait syz-executor 30826 119452 6815 0 3 0x4000080 fsleep syz-executor 30826 520979 6815 0 3 0x4000080 fsleep syz-executor 30470 4509 60802 0 3 0x3000 suspend syz-executor 30470 450718 60802 0 7 0x4081000 syz-executor 30470 282754 60802 0 2 0x4081c00 syz-executor 40762 83207 1 0 2 0x100083 getty 88342 466132 49094 0 2 0xc82 syz-executor 21263 369188 0 0 3 0x14200 bored sosplice *14371 400544 49094 0 7 0x2 syz-executor 17313 395192 49094 0 2 0xc82 syz-executor 60802 504936 49094 0 2 0xc82 syz-executor 42854 479174 49094 0 3 0x82 wait syz-executor 6815 282323 49094 0 2 0xc82 syz-executor 58803 93360 49094 0 2 0xc82 syz-executor 58524 442940 49094 0 2 0xc82 syz-executor 49094 407642 45035 0 3 0x82 kqread syz-executor 45035 365762 93033 0 3 0x10008a sigsusp ksh 93033 17534 9439 0 3 0x98 kqread sshd-session 9439 31848 14907 0 3 0x92 kqread sshd-session 14907 413764 1 0 3 0x88 kqread sshd 86852 7736 12331 74 3 0x1100092 bpf pflogd 12331 268082 1 0 3 0x80 sbwait pflogd 87745 454655 78339 73 3 0x1100090 kqread syslogd 78339 380372 1 0 3 0x100082 sbwait syslogd 64218 123159 1 0 3 0x100080 kqread resolvd 29936 76854 74626 77 3 0x100092 kqread dhcpleased 18423 144101 74626 77 3 0x100092 kqread dhcpleased 74626 331458 1 0 3 0x80 kqread dhcpleased 45799 103155 0 0 2 0x14200 smr 48167 18834 0 0 3 0x14200 pgzero zerothread 72877 26867 0 0 3 0x14200 aiodoned aiodoned 5862 93581 0 0 3 0x14200 syncer update 23340 98154 0 0 3 0x14200 cleaner cleaner 87547 455151 0 0 3 0x14200 reaper reaper 2928 446216 0 0 3 0x14200 pgdaemon pagedaemon 91766 142025 0 0 3 0x14200 bored viomb 50668 344117 0 0 3 0x40014200 acpi0 acpi0 48884 298070 0 0 3 0x40014200 idle1 33570 27864 0 0 3 0x14200 bored softnet7 741 130630 0 0 3 0x14200 bored softnet6 52889 224342 0 0 3 0x14200 bored softnet5 13819 218947 0 0 3 0x14200 bored softnet4 67491 276560 0 0 3 0x14200 bored softnet3 46338 412285 0 0 3 0x14200 bored softnet2 75145 397668 0 0 3 0x14200 bored softnet1 43627 300454 0 0 2 0x14200 softnet0 52794 44621 0 0 2 0x14200 systqmp 28504 103114 0 0 3 0x14200 bored systq 79298 468355 0 0 2 0x14200 softclockmp 57910 160849 0 0 2 0x40014200 softclock 69567 333991 0 0 3 0x40014200 idle0 1 461887 0 0 3 0x82 wait init 0 0 -1 0 3 0x10010200 scheduler swapper ddb{1}> show all locks Process 30470 (syz-executor) thread 0xffff80003c448028 (450718) exclusive rrwlock inode r = 0 (0xfffffd806e0e1a48) #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 rrw_enter+0xc6 sys/kern/kern_rwlock.c:621 #3 VOP_LOCK+0xa3 sys/kern/vfs_vops.c:527 #4 vn_lock+0xa4 sys/kern/vfs_vnops.c:570 #5 vn_write+0x18f sys/kern/vfs_vnops.c:405 #6 dofilewritev+0x242 sys/kern/sys_generic.c:380 #7 sys_write+0xa2 sys/kern/sys_generic.c:300 #8 syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline] #8 syscall+0xbd4 sys/arch/amd64/amd64/trap.c:746 #9 Xsyscall+0x128 ddb{1}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 10255 11144K 11322K 166960K 11959 0 pcb 17 14K 15K 166960K 160 0 rtable 182 10K 10K 166960K 378 0 pf 41 18K 131091K 166960K 170 0 ifaddr 39 6K 8K 166960K 91 0 ifgroup 63 2K 2K 166960K 161 0 sysctl 3 1K 9K 166960K 11 0 counters 72 37K 38K 166960K 164 0 ioctlops 0 0K 4K 166960K 1617 0 iov 0 0K 28K 166960K 42 0 mount 1 1K 1K 166960K 1 0 log 0 0K 0K 166960K 4 0 vnodes 1441 91K 91K 166960K 2090 0 UFS quota 1 32K 32K 166960K 1 0 UFS mount 5 36K 36K 166960K 5 0 shm 2 1K 9K 166960K 15 0 VM map 2 1K 1K 166960K 2 0 sem 12 0K 0K 166960K 26 0 dirhash 12 2K 2K 166960K 27 0 ACPI 1692 195K 286K 166960K 12470 0 file desc 18 65K 106K 166960K 848 0 sigio 0 0K 0K 166960K 18 0 proc 72 115K 164K 166960K 642 0 subproc 72 4K 4K 166960K 81 0 NFS srvsock 1 0K 0K 166960K 1 0 NFS daemon 1 16K 16K 166960K 1 0 ip_moptions 0 0K 0K 166960K 107 0 in_multi 77 5K 7K 166960K 150 0 ether_multi 1 0K 0K 166960K 9 0 mrt 2 0K 0K 166960K 5 0 ISOFS mount 1 32K 32K 166960K 1 0 MSDOSFS mount 1 16K 16K 166960K 1 0 ttys 121 546K 546K 166960K 121 0 exec 0 0K 1K 166960K 487 0 fusefs mount 1 32K 32K 166960K 1 0 tdb 3 0K 0K 166960K 3 0 VM swap 8 62K 64K 166960K 10 0 UVM amap 265 172K 181K 166960K 9424 0 UVM aobj 23 3K 3K 166960K 24 0 pinsyscall 43 86K 100K 166960K 1978 0 memdesc 1 4K 4K 166960K 1 0 crypto data 1 1K 1K 166960K 1 0 ip6_options 2 0K 0K 166960K 42 0 NDP 14 0K 2K 166960K 63 0 temp 60 8647K 8726K 166960K 28302 0 kqueue 13 20K 29K 166960K 181 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 120 142 0 138 1 0 1 1 0 8 0 rtentry 176 123 0 54 5 0 5 5 0 8 0 unpcb 144 761 0 742 7 5 2 6 0 8 1 syncache 336 8 0 8 4 3 1 1 0 8 1 tcpqe 32 3 0 3 2 2 0 1 0 8 0 tcpcb 736 447 0 436 12 5 7 7 0 8 4 arp 136 14 0 4 1 0 1 1 0 8 0 inpcb 328 1169 0 1151 18 10 8 8 0 8 4 nd6 144 20 0 6 1 0 1 1 0 8 0 pkpcb 40 8 0 8 2 1 1 1 0 8 1 kcovpl 48 9 0 1 1 0 1 1 0 8 0 ppxss 1192 33 0 33 2 1 1 1 0 8 1 pppxif 1504 4 0 4 2 2 0 1 0 8 0 pfstscr 40 4 0 2 1 0 1 1 0 8 0 pffrag 232 8 0 2 1 0 1 1 0 482 0 pffrnode 88 5 0 0 1 0 1 1 0 8 0 pffrent 40 15 0 8 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 pfrktable 1344 1 0 1 1 1 0 1 0 8 0 pfanchor 1288 4 0 1 2 1 1 1 0 8 0 pftag 88 1 0 0 1 0 1 1 0 8 0 pfstitem 24 60 0 19 1 0 1 1 0 8 0 pfstkey 128 68 0 27 2 0 2 2 0 8 0 pfstate 384 62 0 23 5 0 5 5 0 8 0 pfrule 1344 29 0 24 2 1 1 2 0 8 0 rttmr 136 1 0 1 1 1 0 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 600 0 253 30 3 27 30 0 8 1 art_table 40 601 0 253 5 0 5 5 0 8 0 art_node 32 120 0 59 1 0 1 1 0 8 0 sysvmsgpl 40 10 0 5 2 1 1 1 0 8 0 semapl 112 21 0 11 1 0 1 1 0 8 0 shmpl 112 21 0 1 1 0 1 1 0 8 0 dirhash 1024 27 0 10 3 0 3 3 0 8 0 dino2pl 256 2923 0 1413 95 0 95 95 0 8 0 ffsino 296 2923 0 1413 117 0 117 117 0 8 0 nchpl 144 4062 0 2365 64 0 64 64 0 8 0 rtmask 32 5 0 5 1 1 0 1 0 8 0 uvmvnodes 80 3472 0 0 71 0 71 71 0 8 0 vnodes 216 3472 0 0 193 0 193 193 0 8 0 namei 1024 14312 0 14312 4 3 1 2 0 8 1 percpumem 16 97 0 46 1 0 1 1 0 8 0 kstatmem 264 96 0 62 4 1 3 3 0 8 0 acpiwqpl 32 1 0 1 1 0 1 1 1 8 1 scsiplug 72 3 0 3 2 1 1 1 0 8 1 scxspl 216 17921 0 17921 10 8 2 7 1 8 2 plimitpl 152 298 0 279 1 0 1 1 0 8 0 sigapl 424 1151 0 1096 7 0 7 7 0 8 0 knotepl 120 544 0 0 17 0 17 17 0 8 0 kqueuepl 224 288 0 276 2 0 2 2 0 8 1 pipepl 344 224 0 196 9 3 6 6 0 8 3 fdescpl 528 1126 0 1094 3 0 3 3 0 8 0 filepl 160 7621 0 7376 27 7 20 20 0 8 5 lockfpl 104 331 0 327 1 0 1 1 0 8 0 lockfspl 48 107 0 104 1 0 1 1 0 8 0 sessionpl 144 30 0 21 1 0 1 1 0 8 0 pgrppl 48 46 0 29 1 0 1 1 0 8 0 ucredpl 104 927 0 913 1 0 1 1 0 8 0 zombiepl 144 1100 0 1096 1 0 1 1 0 8 0 processpl 1232 1151 0 1096 5 0 5 5 0 8 0 procpl 664 2382 0 2315 8 1 7 7 0 8 0 sosppl 168 7 0 7 3 2 1 1 0 8 1 sockpl 752 2102 0 2061 30 18 12 17 0 8 7 mcl64k 65536 4 0 0 1 0 1 1 0 8 0 mcl16k 16384 2 0 0 1 0 1 1 0 8 0 mcl9k 9216 2 0 0 1 0 1 1 0 8 0 mcl8k 8192 3 0 0 1 0 1 1 0 8 0 mcl4k 4096 119 0 0 15 0 15 15 0 8 0 mcl2k 2048 26 0 0 4 0 4 4 0 8 0 mtagpl 96 5 0 0 1 0 1 1 0 8 0 mbufpl 256 275 0 0 18 0 18 18 0 8 0 bufpl 280 6536 0 393 439 0 439 439 0 8 0 anonpl 32 7543 0 0 62 1 61 61 0 246 0 amapchunkpl 152 31097 0 30530 39 12 27 29 0 158 5 amappl16 200 3695 0 3458 33 20 13 15 0 8 0 amappl15 192 3 0 3 2 2 0 1 0 8 0 amappl14 184 129 0 117 1 0 1 1 0 8 0 amappl13 176 11 0 11 2 2 0 1 0 8 0 amappl12 168 1792 0 1759 3 1 2 2 0 8 0 amappl11 160 57 0 43 1 0 1 1 0 8 0 amappl10 152 7 0 7 1 1 0 1 0 8 0 amappl9 144 249 0 249 1 1 0 1 0 8 0 amappl8 136 18 0 15 1 0 1 1 0 8 0 amappl7 128 116 0 104 1 0 1 1 0 8 0 amappl6 120 192 0 188 1 0 1 1 0 8 0 amappl5 112 154 0 144 1 0 1 1 0 8 0 amappl4 104 318 0 297 1 0 1 1 0 8 0 amappl3 96 5386 0 5275 4 1 3 3 0 8 0 amappl2 88 1411 0 1332 2 0 2 2 0 8 0 amappl1 80 12419 0 11814 16 1 15 15 0 8 0 amappl 88 8562 0 8372 5 0 5 5 0 92 0 dma4096 4096 1 0 1 1 1 0 1 0 8 0 dma1024 1024 1 0 0 1 0 1 1 0 8 0 dma256 256 6 0 6 1 1 0 1 0 8 0 dma128 128 253 0 253 1 1 0 1 0 8 0 dma64 64 7 0 7 2 1 1 1 0 8 1 dma32 32 7 0 7 1 1 0 1 0 8 0 dma16 16 19 0 18 1 0 1 1 0 8 0 aobjpl 72 23 0 1 1 0 1 1 0 8 0 uaddrrnd 24 1126 0 1094 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 1126 0 1094 1 0 1 1 0 8 0 vmmpekpl 168 11384 0 11347 3 0 3 3 0 8 0 vmmpepl 168 77465 0 75193 109 6 103 103 0 357 1 vmsppl 488 1125 0 1094 5 0 5 5 0 8 0 rwobjpl 80 26314 0 21645 98 2 96 96 0 8 0 pdppl 4096 2260 0 2188 96 22 74 82 0 8 2 pvpl 32 14540 0 0 119 1 118 118 0 265 0 pmappl 256 1125 0 1094 3 0 3 3 0 8 0 extentpl 40 45 0 27 1 0 1 1 0 8 0 phpool 112 291 0 38 8 0 8 8 0 8 0 ddb{1}> machine ddbcpu 0 Stopped at x86_ipi_db+0x27: addq $0x8,%rsp x86_ipi_db(ffffffff837baff0) 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 scsi_xsh_ioh(ffff8000000a3448,ffff8000000a3448) at scsi_xsh_ioh scsi_xsh_runqueue(ffff8000001a0100) at scsi_xsh_runqueue+0x39d sys/scsi/scsi_base.c:599 scsi_xsh_add(ffff80000019f608) at scsi_xsh_add+0x10e sys/scsi/scsi_base.c:538 sdstrategy(fffffd805d146d30) at sdstrategy+0x21b sys/scsi/sd.c:567 spec_strategy(ffff80003c4670d0) at spec_strategy+0x45 sys/kern/spec_vnops.c:448 VOP_STRATEGY(fffffd800b039438,fffffd805d146d30) at VOP_STRATEGY+0xca sys/kern/vfs_vops.c:639 ufs_strategy(ffff80003c467170) at ufs_strategy+0x1f6 sys/ufs/ufs/ufs_vnops.c:-1 VOP_STRATEGY(fffffd806a9ed288,fffffd805d146d30) at VOP_STRATEGY+0xca sys/kern/vfs_vops.c:639 bwrite(fffffd805d146d30) at bwrite+0x298 sys/kern/vfs_bio.c:745 ffs2_balloc(fffffd806e0e19a8,cf8000,4000,fffffd80097fb548,2,ffff80003c4673e8) at ffs2_balloc+0x18b4 sys/ufs/ffs/ffs_balloc.c:701 ffs_write(ffff80003c467470) at ffs_write+0x4f9 sys/ufs/ffs/ffs_vnops.c:345 end trace frame: 0xffff80003c4674e0, count: 0 ddb{0}> trace x86_ipi_db(ffffffff837baff0) 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 scsi_xsh_ioh(ffff8000000a3448,ffff8000000a3448) at scsi_xsh_ioh scsi_xsh_runqueue(ffff8000001a0100) at scsi_xsh_runqueue+0x39d sys/scsi/scsi_base.c:599 scsi_xsh_add(ffff80000019f608) at scsi_xsh_add+0x10e sys/scsi/scsi_base.c:538 sdstrategy(fffffd805d146d30) at sdstrategy+0x21b sys/scsi/sd.c:567 spec_strategy(ffff80003c4670d0) at spec_strategy+0x45 sys/kern/spec_vnops.c:448 VOP_STRATEGY(fffffd800b039438,fffffd805d146d30) at VOP_STRATEGY+0xca sys/kern/vfs_vops.c:639 ufs_strategy(ffff80003c467170) at ufs_strategy+0x1f6 sys/ufs/ufs/ufs_vnops.c:-1 VOP_STRATEGY(fffffd806a9ed288,fffffd805d146d30) at VOP_STRATEGY+0xca sys/kern/vfs_vops.c:639 bwrite(fffffd805d146d30) at bwrite+0x298 sys/kern/vfs_bio.c:745 ffs2_balloc(fffffd806e0e19a8,cf8000,4000,fffffd80097fb548,2,ffff80003c4673e8) at ffs2_balloc+0x18b4 sys/ufs/ffs/ffs_balloc.c:701 ffs_write(ffff80003c467470) at ffs_write+0x4f9 sys/ufs/ffs/ffs_vnops.c:345 VOP_WRITE(fffffd806a9ed288,ffff80003c467628,7,fffffd80097fb548) at VOP_WRITE+0x101 sys/kern/vfs_vops.c:245 vn_write(fffffd805cecf828,ffff80003c467628,0) at vn_write+0x1d3 sys/kern/vfs_vnops.c:408 dofilewritev(ffff80003c448028,4,ffff80003c467628,0,ffff80003c4676e0) at dofilewritev+0x242 sys/kern/sys_generic.c:380 sys_write(ffff80003c448028,ffff80003c467790,ffff80003c4676e0) at sys_write+0xa2 sys/kern/sys_generic.c:300 syscall(ffff80003c467790) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80003c467790) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:746 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x49c931cab00, count: -20 ddb{0}> machine ddbcpu 1 Stopped at savectx+0xae: movl $0,%gs:0x688 savectx() at savectx+0xae end of kernel end trace frame: 0x7f40d9178080, count: 14 ddb{1}> trace savectx() at savectx+0xae end of kernel end trace frame: 0x7f40d9178080, count: -1