*cpu0: uvm_fault(0xfffffd806b9ed200, 0x0, 0, 1) -> e ddb{1}> trace savectx() at savectx+0xae end of kernel end trace frame: 0x78ead2621b30, count: -1 ddb{1}> show registers rdi 0 rsi 0 rbp 0xffff80003c4d7b00 rbx 0 rdx 0 rcx 0xffff80002a2b74e0 rax 0x3a r8 0xffff80003c4d7a30 r9 0x1 r10 0x880ff6dd65ef6f30 r11 0x7711730c2b44da3f r12 0 r13 0 r14 0xffff80002a2b74e0 r15 0 rip 0xffffffff810ef3ee savectx+0xae cs 0x8 rflags 0x46 rsp 0xffff80003c4d7a80 ss 0x10 savectx+0xae: movl $0,%gs:0x688 ddb{1}> show proc PROC (syz-executor) tid=437983 pid=94723 tcnt=2 stat=onproc flags process=0 proc=0 runpri=50, usrpri=50, slppri=16, nice=20 wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0 forw=0xffffffffffffffff, list=0xffff8000ffff22a8,0xffff80002a2b6d28 process=0xffff80003a026720 user=0xffff80003c4d2000, vmspace=0xfffffd806b9edb88 estcpu=36, cpticks=1, pctcpu=0.0, user=1, sys=0, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 86745 261662 13660 0 2 0 syz-executor *94723 437983 35395 0 7 0 syz-executor 94723 412162 35395 0 3 0x4000080 fsleep syz-executor 45087 160480 79380 0 3 0x80 nanoslp syz-executor 45087 193848 79380 0 3 0x4000080 kqread syz-executor 45087 145426 79380 0 3 0x4000080 fsleep syz-executor 85482 154567 63796 60928 2 0x10 syz-executor 85482 78839 63796 60928 3 0x4000090 lockf syz-executor 85482 272260 63796 60928 3 0x4000090 fsleep syz-executor 2497 147525 12044 0 3 0x80 nanoslp syz-executor 2497 361558 12044 0 3 0x4000080 kqsel syz-executor 2497 484685 12044 0 3 0x4000080 fsleep syz-executor 2497 453293 12044 0 3 0x4000080 fsleep syz-executor 84082 420656 76000 0 3 0x2 biowait syz-executor 35395 45443 76000 0 3 0x82 nanoslp syz-executor 16469 111932 0 0 3 0x14200 acct acct 21324 294820 1 0 3 0x100083 ttyin getty 63796 523561 76000 0 3 0x82 nanoslp syz-executor 67461 400988 0 0 3 0x14200 bored sosplice 34797 13685 76000 0 3 0x82 nanoslp syz-executor 13660 337456 76000 0 3 0x82 nanoslp syz-executor 79380 352054 76000 0 3 0x82 nanoslp syz-executor 12044 507533 76000 0 3 0x82 nanoslp syz-executor 24204 41807 76000 0 2 0x3 syz-executor 76000 389924 42023 0 2 0x3 syz-executor 42023 493776 72686 0 3 0x10008a sigsusp ksh 72686 206777 81923 0 3 0x98 kqread sshd-session 81923 414022 41948 0 3 0x92 kqread sshd-session 41948 286038 1 0 3 0x88 kqread sshd 44902 186686 4334 74 3 0x1100092 bpf pflogd 4334 345966 1 0 3 0x80 sbwait pflogd 79056 346362 18039 73 3 0x1100090 kqread syslogd 18039 460903 1 0 3 0x100082 sbwait syslogd 96645 126105 1 0 3 0x100080 kqread resolvd 84275 514776 2493 77 3 0x100092 kqread dhcpleased 47022 432198 2493 77 3 0x100092 kqread dhcpleased 2493 472925 1 0 3 0x80 kqread dhcpleased 87451 279491 0 0 3 0x14200 bored smr 87713 265289 0 0 2 0x14200 zerothread 86308 188907 0 0 3 0x14200 aiodoned aiodoned 20835 71648 0 0 3 0x14200 syncer update 43837 67560 0 0 3 0x14200 cleaner cleaner 38670 77758 0 0 2 0x14200 reaper 89329 225910 0 0 3 0x14200 pgdaemon pagedaemon 66078 102760 0 0 3 0x14200 bored viomb 13467 426480 0 0 3 0x40014200 acpi0 acpi0 50952 319208 0 0 3 0x40014200 idle1 25790 380883 0 0 3 0x14200 bored softnet7 64412 230429 0 0 3 0x14200 bored softnet6 12852 414169 0 0 3 0x14200 bored softnet5 21503 265622 0 0 3 0x14200 bored softnet4 17002 106186 0 0 3 0x14200 bored softnet3 36919 345881 0 0 3 0x14200 bored softnet2 89968 22898 0 0 3 0x14200 bored softnet1 95393 206078 0 0 3 0x14200 bored softnet0 33178 447861 0 0 3 0x14200 smrbar systqmp 93919 65383 0 0 3 0x14200 bored systq 84078 165733 0 0 3 0x14200 tmoslp softclockmp 57242 207759 0 0 3 0x40014200 tmoslp softclock 19674 394223 0 0 3 0x40014200 idle0 1 360883 0 0 3 0x82 wait init 0 0 -1 0 3 0x10010200 scheduler swapper ddb{1}> show all locks Process 84082 (syz-executor) thread 0xffff80002a2b7778 (420656) exclusive rrwlock inode r = 0 (0xfffffd80737b5dc0) #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 ufs_ihashins+0x4f ufs_ihash sys/ufs/ufs/ufs_ihash.c:-1 [inline] #4 ufs_ihashins+0x4f sys/ufs/ufs/ufs_ihash.c:159 #5 ffs_vget+0x187 sys/ufs/ffs/ffs_vfsops.c:1232 #6 ffs_inode_alloc+0x279 sys/ufs/ffs/ffs_alloc.c:393 #7 ufs_mkdir+0xfc sys/ufs/ufs/ufs_vnops.c:1112 #8 VOP_MKDIR+0x101 sys/kern/vfs_vops.c:394 #9 domkdirat+0x179 sys/kern/vfs_syscalls.c:3113 #10 syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline] #10 syscall+0xb17 sys/arch/amd64/amd64/trap.c:748 #11 Xsyscall+0x128 exclusive rrwlock inode r = 0 (0xfffffd80737b5920) #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 vfs_lookup+0x11c sys/kern/vfs_lookup.c:-1 #6 namei+0x7ca sys/kern/vfs_lookup.c:250 #7 domkdirat+0x8b sys/kern/vfs_syscalls.c:3098 #8 syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline] #8 syscall+0xb17 sys/arch/amd64/amd64/trap.c:748 #9 Xsyscall+0x128 Process 38670 (reaper) thread 0xffff8000ffffc538 (77758) exclusive rwlock kmmaplk r = 0 (0xffffffff838fa468) #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:5168 #3 uvm_unmap+0x7d sys/uvm/uvm_map.c:1792 #4 km_free+0x87 sys/uvm/uvm_km.c:831 #5 uvm_uarea_free+0x4f sys/uvm/uvm_glue.c:304 #6 reaper+0x1aa sys/kern/kern_exit.c:493 #7 proc_trampoline+0x10 Process 33178 (systqmp) thread 0xffff8000ffffe530 (447861) shared rwlock systqmp r = 0 (0xffffffff83818178) #0 witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline] #0 witness_lock+0x5f1 sys/kern/subr_witness.c:1160 #1 taskq_thread+0x12a sys/kern/kern_task.c:442 #2 proc_trampoline+0x10 ddb{1}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 10254 11075K 12468K 166960K 13902 0 pcb 17 16K 18K 166960K 265 0 rtable 216 9K 10K 166960K 981 0 pf 38 18K 82K 166960K 287 0 ifaddr 42 8K 8K 166960K 217 0 ifgroup 59 2K 2K 166960K 316 0 sysctl 4 1K 9K 166960K 17 0 counters 70 37K 38K 166960K 474 0 ioctlops 0 0K 4K 166960K 1845 0 iov 0 0K 28K 166960K 93 0 mount 1 1K 1K 166960K 1 0 log 0 0K 0K 166960K 4 0 vnodes 1652 104K 104K 166960K 3444 0 UFS quota 1 32K 32K 166960K 1 0 UFS mount 5 36K 36K 166960K 5 0 shm 2 1K 9K 166960K 24 0 VM map 2 1K 1K 166960K 2 0 sem 12 0K 0K 166960K 53 0 dirhash 12 2K 2K 166960K 30 0 ACPI 1692 195K 286K 166960K 12470 0 file desc 16 57K 240K 166960K 2030 0 sigio 0 0K 0K 166960K 267 0 proc 72 115K 164K 166960K 1421 0 subproc 72 4K 4K 166960K 288 0 NFS srvsock 1 0K 0K 166960K 1 0 NFS daemon 1 16K 16K 166960K 1 0 ip_moptions 1 0K 0K 166960K 355 0 in_multi 88 6K 7K 166960K 434 0 ether_multi 1 0K 0K 166960K 16 0 mrt 1 0K 0K 166960K 9 0 ISOFS mount 1 32K 32K 166960K 1 0 MSDOSFS mount 1 16K 16K 166960K 1 0 ttys 235 1049K 1049K 166960K 235 0 exec 0 0K 1K 166960K 963 0 fusefs mount 1 32K 32K 166960K 1 0 pfkey data 0 0K 0K 166960K 36 0 tdb 3 0K 0K 166960K 3 0 VM swap 8 62K 64K 166960K 10 0 UVM amap 235 181K 186K 166960K 18497 0 UVM aobj 5 2K 2K 166960K 6 0 pinsyscall 41 82K 102K 166960K 3763 0 memdesc 1 4K 4K 166960K 1 0 crypto data 1 1K 1K 166960K 1 0 ip6_options 0 0K 0K 166960K 104 0 NDP 15 0K 2K 166960K 156 0 temp 77 8652K 8905K 166960K 46065 0 kqueue 13 20K 34K 166960K 305 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 120 224 0 221 2 1 1 2 0 8 0 rtentry 176 359 0 273 5 0 5 5 0 8 0 unpcb 144 1301 0 1281 9 8 1 4 0 8 0 syncache 336 18 0 18 5 4 1 1 0 8 1 tcpcb 736 685 0 678 14 13 1 7 0 8 0 arp 128 42 0 30 1 0 1 1 0 8 0 inpcb 328 2015 0 2002 16 14 2 12 0 8 0 nd6 144 71 0 53 1 0 1 1 0 8 0 pkpcb 40 11 0 11 3 3 0 1 0 8 0 kcovpl 48 32 0 24 1 0 1 1 0 8 0 ppxss 1192 159 0 159 2 2 0 1 0 8 0 pppxif 1504 106 0 106 3 3 0 1 0 8 0 pfstscr 40 2 0 2 2 2 0 1 0 8 0 pffrag 232 9 0 4 1 0 1 1 0 482 0 pffrnode 88 8 0 4 1 0 1 1 0 8 0 pffrent 40 13 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 10 0 10 3 3 0 1 0 8 0 pfanchor 1288 4 0 3 2 1 1 1 0 8 0 pftag 88 6 0 3 1 0 1 1 0 8 0 pfstitem 24 137 0 48 1 0 1 1 0 8 0 pfstkey 128 142 0 53 4 0 4 4 0 8 0 pfstate 384 139 0 51 10 0 10 10 0 8 0 pfrule 1344 38 0 33 2 1 1 2 0 8 0 rttmr 136 1 0 1 1 1 0 1 0 8 0 art_heap8 4096 2 0 0 2 0 2 2 0 8 0 art_heap4 256 1703 0 1323 36 11 25 31 0 8 0 art_table 40 1705 0 1323 5 0 5 5 0 8 0 art_node 32 358 0 284 1 0 1 1 0 8 0 sysvmsgpl 40 12 0 9 1 0 1 1 0 8 0 semapl 112 50 0 40 1 0 1 1 0 8 0 shmpl 112 3 0 1 1 0 1 1 0 8 0 dirhash 1024 29 0 12 3 0 3 3 0 8 0 dino2pl 256 4576 0 3018 99 1 98 98 0 8 0 ffsino 296 4576 0 3018 122 1 121 121 0 8 0 nchpl 144 6848 0 5082 66 0 66 66 0 8 0 rtmask 32 11 0 11 2 2 0 1 0 8 0 uvmvnodes 80 5926 0 0 121 0 121 121 0 8 0 vnodes 216 5926 0 0 330 0 330 330 0 8 0 namei 1024 26011 0 26010 5 3 2 2 0 8 1 percpumem 16 252 0 202 1 0 1 1 0 8 0 pfiaddrpl 120 3 0 3 2 2 0 1 0 8 0 kstatmem 264 188 0 158 4 1 3 3 0 8 0 acpiwqpl 32 1 0 1 1 0 1 1 1 8 1 scsiplug 72 9 0 9 2 2 0 1 0 8 0 scxspl 216 40797 0 40796 15 14 1 8 1 8 0 plimitpl 152 459 0 442 1 0 1 1 0 8 0 sigapl 424 2280 0 2226 9 2 7 9 0 8 0 knotepl 120 780 0 0 24 0 24 24 0 8 0 kqueuepl 224 670 0 659 10 9 1 5 0 8 0 pipepl 344 379 0 352 9 6 3 9 0 8 0 fdescpl 528 2230 0 2200 3 0 3 3 0 8 0 filepl 160 14161 0 13936 23 10 13 20 0 8 0 lockfpl 104 1021 0 1016 3 2 1 2 0 8 0 lockfspl 48 411 0 407 1 0 1 1 0 8 0 sessionpl 144 57 0 48 1 0 1 1 0 8 0 pgrppl 48 175 0 157 1 0 1 1 0 8 0 ucredpl 104 2087 0 2071 1 0 1 1 0 8 0 zombiepl 144 2237 0 2236 2 1 1 1 0 8 0 processpl 1248 2280 0 2226 6 0 6 6 0 8 0 procpl 664 4842 0 4778 9 2 7 9 0 8 0 sosppl 168 7 0 7 2 2 0 1 0 8 0 sockpl 752 3661 0 3625 21 17 4 17 0 8 0 mcl64k 65536 5 0 0 1 0 1 1 0 8 0 mcl16k 16384 3 0 0 1 0 1 1 0 8 0 mcl8k 8192 3 0 0 1 0 1 1 0 8 0 mcl4k 4096 113 0 0 14 0 14 14 0 8 0 mcl2k2 2112 1 0 0 1 0 1 1 0 8 0 mcl2k 2048 70 0 0 8 0 8 8 0 8 0 mtagpl 96 14 0 0 1 0 1 1 0 8 0 mbufpl 256 3047 0 0 189 0 189 189 0 8 0 bufpl 280 17018 0 10875 439 0 439 439 0 8 0 anonpl 32 12799 0 0 104 0 104 104 0 246 0 amapchunkpl 152 66673 0 66014 60 25 35 35 0 158 3 amappl16 200 7185 0 7158 45 38 7 25 0 8 0 amappl15 192 2 0 2 1 1 0 1 0 8 0 amappl14 184 185 0 173 1 0 1 1 0 8 0 amappl13 176 7 0 7 3 3 0 1 0 8 0 amappl12 168 3286 0 3256 4 2 2 3 0 8 0 amappl11 160 57 0 43 1 0 1 1 0 8 0 amappl10 152 7 0 6 1 0 1 1 0 8 0 amappl9 144 245 0 245 2 2 0 1 0 8 0 amappl8 136 32 0 29 1 0 1 1 0 8 0 amappl7 128 170 0 157 1 0 1 1 0 8 0 amappl6 120 433 0 429 1 0 1 1 0 8 0 amappl5 112 235 0 224 1 0 1 1 0 8 0 amappl4 104 369 0 350 1 0 1 1 0 8 0 amappl3 96 12161 0 12051 4 0 4 4 0 8 0 amappl2 88 1071 0 1004 2 0 2 2 0 8 0 amappl1 80 19544 0 18947 15 0 15 15 0 8 0 amappl 88 17078 0 16918 5 0 5 5 0 92 0 dma32768 32768 1 0 1 1 1 0 1 0 8 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 128 256 0 256 2 2 0 1 0 8 0 dma64 64 6 0 6 1 1 0 1 0 8 0 dma32 32 8 0 8 2 2 0 1 0 8 0 dma16 16 19 0 18 1 0 1 1 0 8 0 aobjpl 72 5 0 1 1 0 1 1 0 8 0 uaddrrnd 24 2230 0 2200 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 2230 0 2200 1 0 1 1 0 8 0 vmmpekpl 168 18414 0 18361 3 0 3 3 0 8 0 vmmpepl 168 146462 0 144498 113 17 96 110 0 357 0 vmsppl 488 2229 0 2200 5 0 5 5 0 8 0 rwobjpl 80 46074 0 39202 143 1 142 143 0 8 0 pdppl 4096 4468 0 4400 130 56 74 86 0 8 6 pvpl 32 20241 0 0 164 0 164 164 0 265 0 pmappl 256 2229 0 2200 3 0 3 3 0 8 0 extentpl 40 45 0 27 1 0 1 1 0 8 0 phpool 112 515 0 91 13 0 13 13 0 8 0 ddb{1}> machine ddbcpu 0 Stopped at x86_ipi_db+0x27: addq $0x8,%rsp x86_ipi_db(ffffffff8378dff0) 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+0xf kd_curproc sys/dev/kcov.c:580 [inline] __sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0xf sys/dev/kcov.c:153 intr_handler(ffff80002a3447b0,ffff800000079a80) at intr_handler+0xe9 sys/arch/amd64/amd64/intr.c:559 Xintr_ioapic_edge23_untramp() at Xintr_ioapic_edge23_untramp+0x18f Xspllower() at Xspllower+0x1d cnputc(6d) at cnputc+0x67 sys/dev/cons.c:218 db_putchar(6d) at db_putchar+0x36d sys/ddb/db_output.c:155 kprintf() at kprintf+0x29a5 sys/kern/subr_prf.c:-1 db_printf(ffffffff83314a5c) at db_printf+0x9b sys/kern/subr_prf.c:-1 fault(ffffffff833d614b) at fault+0xa7 sys/arch/amd64/amd64/trap.c:161 kpageflttrap(ffff80002a344c60,0) at kpageflttrap+0x37d sys/arch/amd64/amd64/trap.c:296 kerntrap(ffff80002a344c60) at kerntrap+0x198 sys/arch/amd64/amd64/trap.c:491 end trace frame: 0xffff80002a344ce0, count: 0 ddb{0}> trace x86_ipi_db(ffffffff8378dff0) 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+0xf kd_curproc sys/dev/kcov.c:580 [inline] __sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0xf sys/dev/kcov.c:153 intr_handler(ffff80002a3447b0,ffff800000079a80) at intr_handler+0xe9 sys/arch/amd64/amd64/intr.c:559 Xintr_ioapic_edge23_untramp() at Xintr_ioapic_edge23_untramp+0x18f Xspllower() at Xspllower+0x1d cnputc(6d) at cnputc+0x67 sys/dev/cons.c:218 db_putchar(6d) at db_putchar+0x36d sys/ddb/db_output.c:155 kprintf() at kprintf+0x29a5 sys/kern/subr_prf.c:-1 db_printf(ffffffff83314a5c) at db_printf+0x9b sys/kern/subr_prf.c:-1 fault(ffffffff833d614b) at fault+0xa7 sys/arch/amd64/amd64/trap.c:161 kpageflttrap(ffff80002a344c60,0) at kpageflttrap+0x37d sys/arch/amd64/amd64/trap.c:296 kerntrap(ffff80002a344c60) at kerntrap+0x198 sys/arch/amd64/amd64/trap.c:491 alltraps_kern_meltdown() at alltraps_kern_meltdown+0x7b dt_ioctl_record_stop(ffff800001649000) at dt_ioctl_record_stop+0x108 sys/dev/dt/dt_dev.c:586 dtclose(11e5f,81,2000,ffff8000ffff22a8) at dtclose+0x109 dt_pcb_purge sys/dev/dt/dt_dev.c:-1 [inline] dtclose(11e5f,81,2000,ffff8000ffff22a8) at dtclose+0x109 sys/dev/dt/dt_dev.c:232 spec_close(ffff80002a344e10) at spec_close+0x466 sys/kern/spec_vnops.c:-1 VOP_CLOSE(fffffd800da8b9a8,81,fffffd80097fb548,ffff8000ffff22a8) at VOP_CLOSE+0x132 sys/kern/vfs_vops.c:156 vn_closefile(fffffd8062d5acf0,ffff8000ffff22a8) at vn_closefile+0x12b vn_close sys/kern/vfs_vnops.c:292 [inline] vn_closefile(fffffd8062d5acf0,ffff8000ffff22a8) at vn_closefile+0x12b sys/kern/vfs_vnops.c:615 fdrop(fffffd8062d5acf0,ffff8000ffff22a8) at fdrop+0x121 sys/kern/kern_descrip.c:1280 closef(fffffd8062d5acf0,ffff8000ffff22a8) at closef+0x192 sys/kern/kern_descrip.c:1264 fdfree(ffff8000ffff22a8) at fdfree+0x116 sys/kern/kern_descrip.c:1195 exit1(ffff8000ffff22a8,0,0,1) at exit1+0x576 sys/kern/kern_exit.c:215 sys_exit(ffff8000ffff22a8,ffff80002a345180,ffff80002a3450d0) at sys_exit+0x1a sys/kern/kern_exit.c:-1 syscall(ffff80002a345180) at syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80002a345180) at syscall+0xb17 sys/arch/amd64/amd64/trap.c:748 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7694d019a740, count: -27 ddb{0}> machine ddbcpu 1 Stopped at savectx+0xae: movl $0,%gs:0x688 savectx() at savectx+0xae end of kernel end trace frame: 0x78ead2621b30, count: 14 ddb{1}> trace savectx() at savectx+0xae end of kernel end trace frame: 0x78ead2621b30, count: -1