@uvm_fault(0xfffffd80605e33f8, 0x0, 0, 1) -> e fatal page fault in supervisor mode trap type 6 code 0 rip ffffffff81577d98 cs 8 rflags 10207 cr2 0 cpl 0 rsp ffff800034009920 gsbase 0xffff8000299edff0 kgsbase 0x0 panic: trap type 6, code=0, pc=ffffffff81577d98 Starting stack trace... panic(ffffffff833a20e5) at panic+0x1d0 sys/kern/subr_prf.c:229 kerntrap(ffff800034009870) at kerntrap+0x30b alltraps_kern_meltdown() at alltraps_kern_meltdown+0x7b dt_ioctl_record_stop(ffff800001481000) at dt_ioctl_record_stop+0x108 sys/dev/dt/dt_dev.c:586 dtclose(11e5f,81,2000,ffff8000ffff2d08) at dtclose+0x109 dt_pcb_purge sys/dev/dt/dt_dev.c:-1 [inline] dtclose(11e5f,81,2000,ffff8000ffff2d08) at dtclose+0x109 sys/dev/dt/dt_dev.c:232 spec_close(ffff800034009a20) at spec_close+0x466 sys/kern/spec_vnops.c:-1 VOP_CLOSE(fffffd8061bf1c08,81,fffffd80097fb548,ffff8000ffff2d08) at VOP_CLOSE+0x132 sys/kern/vfs_vops.c:156 vn_closefile(fffffd805d52a1f0,ffff8000ffff2d08) at vn_closefile+0x12b vn_close sys/kern/vfs_vnops.c:292 [inline] vn_closefile(fffffd805d52a1f0,ffff8000ffff2d08) at vn_closefile+0x12b sys/kern/vfs_vnops.c:615 fdrop(fffffd805d52a1f0,ffff8000ffff2d08) at fdrop+0x121 sys/kern/kern_descrip.c:1280 closef(fffffd805d52a1f0,ffff8000ffff2d08) at closef+0x192 sys/kern/kern_descrip.c:1264 fdfree(ffff8000ffff2d08) at fdfree+0x116 sys/kern/kern_descrip.c:1195 exit1(ffff8000ffff2d08,0,0,1) at exit1+0x576 sys/kern/kern_exit.c:215 sys_exit(ffff8000ffff2d08,ffff800034009d90,ffff800034009ce0) at sys_exit+0x1a sys/kern/kern_exit.c:-1 syscall(ffff800034009d90) at syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff800034009d90) at syscall+0xb17 sys/arch/amd64/amd64/trap.c:746 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7e9262b60be0, count: 242 End of stack trace. WARNING: SPL NOT LOWERED ON SYSCALL 83 1398932480 EXIT 0 4 Stopped at savectx+0xae: movl $0,%gs:0x688 TID PID UID PRFLAGS PFLAGS CPU COMMAND *207030 11260 0 0x10 0 1 syz-executor 270102 84696 0 0x2 0 0 syz-executor savectx() at savectx+0xae end of kernel end trace frame: 0x7c506afdb440, 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(0xfffffd80605e33f8, 0x0, 0, 1) -> e ddb{1}> trace savectx() at savectx+0xae end of kernel end trace frame: 0x7c506afdb440, count: -1 ddb{1}> show registers rdi 0 rsi 0 rbp 0xffff800039821340 rbx 0 rdx 0 rcx 0xffff800039814568 rax 0x3b r8 0xffff800039821270 r9 0x1 r10 0x58c1f712a39e9ce0 r11 0x1cd54b14b513f502 r12 0 r13 0 r14 0xffff800039814568 r15 0 rip 0xffffffff813a73ee savectx+0xae cs 0x8 rflags 0x46 rsp 0xffff8000398212c0 ss 0x10 savectx+0xae: movl $0,%gs:0x688 ddb{1}> show proc PROC (syz-executor) tid=207030 pid=11260 tcnt=2 stat=onproc flags process=10 proc=0 runpri=86, usrpri=86, slppri=32, nice=20 wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0 forw=0xffffffffffffffff, list=0xffff800039814800,0xffff800039814aa8 process=0xffff80003c424e90 user=0xffff80003981c000, vmspace=0xfffffd80605e3210 estcpu=36, cpticks=4, pctcpu=0.0, user=2, sys=2, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 485 113990 49505 0 2 0 syz-executor 485 303692 49505 0 3 0x4000080 fsleep syz-executor 74146 163595 33625 0 3 0 kmmaplk syz-executor *11260 207030 76009 0 7 0x10 syz-executor 11260 225374 76009 0 3 0x4000090 fsleep syz-executor 31384 184530 7647 0 2 0 syz-executor 31384 173970 7647 0 2 0x4000000 syz-executor 31384 120376 7647 0 3 0x4000080 fsleep syz-executor 57261 336314 67549 0 2 0 syz-executor 57261 130140 67549 0 3 0x4000080 fsleep syz-executor 57261 312658 67549 0 3 0x4000080 fsleep syz-executor 57261 49066 67549 0 3 0x4000080 fsleep syz-executor 99217 190759 0 0 3 0x14200 acct acct 68048 130403 1 0 3 0x100083 ttyin getty 76009 318469 4567 0 3 0x82 nanoslp syz-executor 66271 342701 0 0 3 0x14200 bored sosplice 7647 282956 4567 0 3 0x82 nanoslp syz-executor 37336 133511 4567 0 3 0x82 nanoslp syz-executor 33625 330700 4567 0 3 0x82 nanoslp syz-executor 49505 67105 4567 0 3 0x82 nanoslp syz-executor 67549 282444 4567 0 3 0x82 nanoslp syz-executor 79597 218730 4567 0 3 0x82 nanoslp syz-executor 84696 270102 4567 0 7 0x2 syz-executor 4567 427327 4819 0 3 0x82 kqread syz-executor 4819 518932 70872 0 3 0x10008a sigsusp ksh 70872 406823 97686 0 3 0x98 kqread sshd-session 97686 215546 75433 0 3 0x92 kqread sshd-session 75433 335460 1 0 3 0x88 kqread sshd 61453 338288 74865 74 3 0x1100092 bpf pflogd 74865 179059 1 0 3 0x80 sbwait pflogd 50856 216416 73291 73 3 0x1100090 kqread syslogd 73291 157349 1 0 3 0x100082 sbwait syslogd 3285 140436 1 0 3 0x100080 kqread resolvd 9173 407955 0 0 3 0x14200 bored smr 87483 91871 0 0 2 0x14200 zerothread 52837 354464 0 0 3 0x14200 aiodoned aiodoned 38250 116029 0 0 3 0x14200 syncer update 63511 355439 0 0 3 0x14200 cleaner cleaner 4472 27154 0 0 3 0x14200 kmmaplk reaper 79824 358683 0 0 3 0x14200 pgdaemon pagedaemon 9943 472867 0 0 3 0x14200 bored viomb 76188 193515 0 0 3 0x40014200 acpi0 acpi0 18972 118197 0 0 3 0x40014200 idle1 33510 307088 0 0 3 0x14200 bored softnet7 9024 524143 0 0 3 0x14200 bored softnet6 96173 147090 0 0 3 0x14200 bored softnet5 32834 467492 0 0 3 0x14200 bored softnet4 75649 110195 0 0 3 0x14200 bored softnet3 23197 169272 0 0 3 0x14200 bored softnet2 13898 197350 0 0 3 0x14200 bored softnet1 7180 391441 0 0 3 0x14200 netlock softnet0 50679 266829 0 0 2 0x14200 systqmp 42317 35262 0 0 3 0x14200 bored systq 63386 516468 0 0 3 0x14200 tmoslp softclockmp 92494 102376 0 0 3 0x40014200 tmoslp softclock 44291 323961 0 0 3 0x40014200 idle0 1 16745 0 0 3 0x82 wait init 0 0 -1 0 3 0x10010200 scheduler swapper ddb{1}> show all locks ddb{1}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 10221 11077K 11229K 166960K 12480 0 pcb 18 16K 17K 166960K 448 0 rtable 161 10K 12K 166960K 526 0 pf 39 18K 67486K 166960K 461 0 ifaddr 33 5K 8K 166960K 145 0 ifgroup 55 2K 3K 166960K 279 0 sysctl 4 1K 9K 166960K 23 0 counters 68 36K 38K 166960K 318 0 ioctlops 0 0K 5K 166960K 1861 0 iov 0 0K 28K 166960K 188 0 mount 1 1K 1K 166960K 1 0 log 0 0K 0K 166960K 4 0 vnodes 1400 88K 89K 166960K 2676 0 UFS quota 1 32K 32K 166960K 1 0 UFS mount 5 36K 36K 166960K 5 0 shm 2 5K 13K 166960K 25 0 VM map 2 1K 1K 166960K 2 0 sem 12 0K 0K 166960K 67 0 dirhash 12 2K 2K 166960K 48 0 ACPI 1692 195K 286K 166960K 12470 0 file desc 17 61K 110K 166960K 1810 0 sigio 0 0K 0K 166960K 93 0 proc 66 83K 164K 166960K 746 0 subproc 72 4K 4K 166960K 82 0 NFS srvsock 1 0K 0K 166960K 1 0 NFS daemon 1 16K 16K 166960K 1 0 ip_moptions 1 0K 0K 166960K 202 0 in_multi 63 4K 7K 166960K 173 0 ether_multi 1 0K 0K 166960K 17 0 mrt 2 0K 0K 166960K 10 0 ISOFS mount 1 32K 32K 166960K 1 0 MSDOSFS mount 1 16K 16K 166960K 1 0 ttys 103 466K 466K 166960K 103 0 exec 0 0K 1K 166960K 753 0 fusefs mount 1 32K 32K 166960K 1 0 pfkey data 0 0K 0K 166960K 2 0 tdb 3 0K 0K 166960K 3 0 VM swap 8 62K 64K 166960K 10 0 UVM amap 215 143K 187K 166960K 18385 0 UVM aobj 39 4K 6K 166960K 47 0 pinsyscall 36 72K 102K 166960K 2952 0 memdesc 1 4K 4K 166960K 1 0 crypto data 1 1K 1K 166960K 1 0 ip6_options 0 0K 0K 166960K 112 0 NDP 12 0K 2K 166960K 105 0 temp 84 8656K 8772K 166960K 71380 0 kqueue 8 13K 32K 166960K 392 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 120 170 0 169 1 0 1 1 0 8 0 rtentry 176 150 0 92 5 0 5 5 0 8 0 unpcb 144 1409 0 1399 12 6 6 6 0 8 5 syncache 336 11 0 11 3 2 1 1 0 8 1 tcpqe 32 3 0 3 2 2 0 1 0 8 0 tcpcb 736 728 0 719 25 21 4 13 0 8 3 arp 136 16 0 8 1 0 1 1 0 8 0 ipq 40 1 0 1 1 1 0 1 0 8 0 ipqe 40 3 0 3 1 1 0 1 0 8 0 inpcb 328 2064 0 2052 31 24 7 20 0 8 5 nd6 144 21 0 9 1 0 1 1 0 8 0 pkpcb 40 14 0 14 3 3 0 1 0 8 0 kcovpl 48 9 0 1 1 0 1 1 0 8 0 mppekey 1024 2 0 2 2 2 0 1 0 8 0 ppxss 1192 97 0 97 2 1 1 1 0 8 1 pppxif 1504 13 0 13 4 3 1 2 0 8 1 pfstscr 40 9 0 8 2 1 1 1 0 8 0 pffrag 232 15 0 9 1 0 1 1 0 482 0 pffrnode 88 8 0 4 1 0 1 1 0 8 0 pffrent 40 38 0 31 1 0 1 1 0 8 0 pfosfp 40 1430 0 1005 5 0 5 5 0 8 0 pfosfpen 112 1430 0 714 21 0 21 21 0 8 0 pfrktable 1344 18 0 18 1 1 0 1 0 8 0 pfanchor 1288 9 0 3 1 0 1 1 0 8 0 pftag 88 6 0 4 1 0 1 1 0 8 0 pfstitem 24 172 0 62 1 0 1 1 0 8 0 pfstkey 128 181 0 71 4 0 4 4 0 8 0 pfstate 384 176 0 67 13 2 11 11 0 8 0 pfrule 1344 35 0 30 2 1 1 2 0 8 0 rttmr 136 2 0 2 2 2 0 1 0 8 0 art_heap8 4096 3 0 0 3 0 3 3 0 8 0 art_heap4 256 625 0 321 28 8 20 28 0 8 0 art_table 40 628 0 321 5 0 5 5 0 8 0 art_node 32 143 0 94 1 0 1 1 0 8 0 sysvmsgpl 40 17 0 12 1 0 1 1 0 8 0 semapl 112 65 0 55 1 0 1 1 0 8 0 shmpl 112 44 0 8 2 0 2 2 0 8 0 dirhash 1024 42 0 25 3 0 3 3 0 8 0 dino2pl 256 4864 0 3349 97 1 96 96 0 8 0 ffsino 296 4864 0 3349 118 0 118 118 0 8 0 nchpl 144 7357 0 6824 64 31 33 64 0 8 8 rtmask 32 24 0 24 3 2 1 1 0 8 1 uvmvnodes 80 5541 0 0 114 0 114 114 0 8 0 vnodes 216 5541 0 0 308 0 308 308 0 8 0 namei 1024 24065 0 24065 2 1 1 2 0 8 1 percpumem 16 174 0 125 1 0 1 1 0 8 0 pfiaddrpl 120 5 0 5 1 1 0 1 0 8 0 kstatmem 264 176 0 148 4 1 3 3 0 8 0 acpiwqpl 32 1 0 1 1 0 1 1 1 8 1 scsiplug 72 6 0 6 4 3 1 1 0 8 1 scxspl 216 40665 0 40665 12 11 1 7 1 8 1 plimitpl 152 355 0 338 1 0 1 1 0 8 0 sigapl 424 2114 0 2062 7 0 7 7 0 8 0 knotepl 120 557 0 0 17 0 17 17 0 8 0 kqueuepl 224 685 0 676 8 3 5 5 0 8 4 pipepl 344 282 0 254 3 0 3 3 0 8 0 fdescpl 528 2085 0 2057 3 0 3 3 0 8 0 filepl 160 12540 0 12331 24 10 14 20 0 8 3 lockfpl 104 599 0 598 1 0 1 1 0 8 0 lockfspl 48 250 0 249 1 0 1 1 0 8 0 sessionpl 144 34 0 26 1 0 1 1 0 8 0 pgrppl 48 56 0 40 1 0 1 1 0 8 0 ucredpl 104 2031 0 2019 1 0 1 1 0 8 0 zombiepl 144 2404 0 2402 1 0 1 1 0 8 0 processpl 1232 2114 0 2062 5 0 5 5 0 8 0 procpl 664 4989 0 4929 9 2 7 7 0 8 1 sosppl 168 16 0 16 3 2 1 1 0 8 1 sockpl 752 3731 0 3707 41 25 16 26 0 8 13 mcl64k 65536 26 0 0 4 0 4 4 0 8 0 mcl16k 16384 7 0 0 1 0 1 1 0 8 0 mcl12k 12288 2 0 0 1 0 1 1 0 8 0 mcl9k 9216 3 0 0 1 0 1 1 0 8 0 mcl8k 8192 9 0 0 2 0 2 2 0 8 0 mcl4k 4096 123 0 0 16 0 16 16 0 8 0 mcl2k2 2112 1 0 0 1 0 1 1 0 8 0 mcl2k 2048 32 0 0 4 0 4 4 0 8 0 mtagpl 96 4 0 0 1 0 1 1 0 8 0 mbufpl 256 1173 0 0 72 0 72 72 0 8 0 bufpl 280 15782 0 9639 440 0 440 440 0 8 0 anonpl 32 11541 0 0 93 0 93 93 0 246 0 amapchunkpl 152 62469 0 62011 48 20 28 32 0 158 6 amappl16 200 6090 0 6043 49 35 14 28 0 8 8 amappl15 192 6 0 6 1 1 0 1 0 8 0 amappl14 184 140 0 131 1 0 1 1 0 8 0 amappl13 176 5 0 5 1 1 0 1 0 8 0 amappl12 168 2760 0 2732 4 1 3 3 0 8 0 amappl11 160 50 0 42 1 0 1 1 0 8 0 amappl10 152 5 0 4 1 0 1 1 0 8 0 amappl9 144 262 0 261 2 1 1 1 0 8 0 amappl8 136 23 0 21 1 0 1 1 0 8 0 amappl7 128 120 0 110 1 0 1 1 0 8 0 amappl6 120 194 0 190 1 0 1 1 0 8 0 amappl5 112 128 0 121 1 0 1 1 0 8 0 amappl4 104 358 0 340 1 0 1 1 0 8 0 amappl3 96 10905 0 10819 4 1 3 3 0 8 0 amappl2 88 2384 0 2321 2 0 2 2 0 8 0 amappl1 80 16908 0 16398 16 2 14 15 0 8 0 amappl 88 17351 0 17192 5 0 5 5 0 92 0 dma8192 8192 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 8 0 8 2 2 0 1 0 8 0 dma128 128 256 0 256 3 2 1 1 0 8 1 dma64 64 6 0 6 1 1 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 46 0 8 1 0 1 1 0 8 0 uaddrrnd 24 2085 0 2057 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 2085 0 2057 1 0 1 1 0 8 0 vmmpekpl 168 18565 0 18528 2 0 2 2 0 8 0 vmmpepl 168 135594 0 133881 112 24 88 112 0 357 3 vmsppl 488 2084 0 2057 6 2 4 5 0 8 0 rwobjpl 80 41409 0 35026 132 1 131 131 0 8 0 pdppl 4096 4178 0 4114 112 44 68 86 0 8 4 pvpl 32 19666 0 0 160 1 159 159 0 265 0 pmappl 256 2084 0 2057 3 0 3 3 0 8 0 extentpl 40 45 0 27 1 0 1 1 0 8 0 phpool 112 382 0 83 9 0 9 9 0 8 0 ddb{1}> machine ddbcpu 0 Stopped at x86_ipi_db+0x27: addq $0x8,%rsp x86_ipi_db(ffffffff8379dff0) 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+0x2c kd_curproc sys/dev/kcov.c:584 [inline] __sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0x2c sys/dev/kcov.c:153 __mp_lock(ffffffff83892960) at __mp_lock+0x1a3 __mp_lock_spin sys/kern/kern_lock.c:134 [inline] __mp_lock(ffffffff83892960) at __mp_lock+0x1a3 sys/kern/kern_lock.c:165 softintr_dispatch(2) at softintr_dispatch+0x125 sys/kern/kern_softintr.c:83 dosoftint(2) at dosoftint+0x54 sys/arch/amd64/amd64/intr.c:847 Xsofttty() at Xsofttty+0x27 __mp_lock(ffffffff83892960) at __mp_lock+0x192 __mp_lock_spin sys/kern/kern_lock.c:134 [inline] __mp_lock(ffffffff83892960) at __mp_lock+0x192 sys/kern/kern_lock.c:165 softintr_dispatch(0) at softintr_dispatch+0x125 sys/kern/kern_softintr.c:83 dosoftint(0) at dosoftint+0x54 sys/arch/amd64/amd64/intr.c:847 Xsoftclock() at Xsoftclock+0x27 __sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0x38 sys/dev/kcov.c:-1 __mp_lock(ffffffff83892960) at __mp_lock+0x1a3 __mp_lock_spin sys/kern/kern_lock.c:134 [inline] __mp_lock(ffffffff83892960) at __mp_lock+0x1a3 sys/kern/kern_lock.c:165 end trace frame: 0xffff80002a325790, count: 0 ddb{0}> trace x86_ipi_db(ffffffff8379dff0) 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+0x2c kd_curproc sys/dev/kcov.c:584 [inline] __sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0x2c sys/dev/kcov.c:153 __mp_lock(ffffffff83892960) at __mp_lock+0x1a3 __mp_lock_spin sys/kern/kern_lock.c:134 [inline] __mp_lock(ffffffff83892960) at __mp_lock+0x1a3 sys/kern/kern_lock.c:165 softintr_dispatch(2) at softintr_dispatch+0x125 sys/kern/kern_softintr.c:83 dosoftint(2) at dosoftint+0x54 sys/arch/amd64/amd64/intr.c:847 Xsofttty() at Xsofttty+0x27 __mp_lock(ffffffff83892960) at __mp_lock+0x192 __mp_lock_spin sys/kern/kern_lock.c:134 [inline] __mp_lock(ffffffff83892960) at __mp_lock+0x192 sys/kern/kern_lock.c:165 softintr_dispatch(0) at softintr_dispatch+0x125 sys/kern/kern_softintr.c:83 dosoftint(0) at dosoftint+0x54 sys/arch/amd64/amd64/intr.c:847 Xsoftclock() at Xsoftclock+0x27 __sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0x38 sys/dev/kcov.c:-1 __mp_lock(ffffffff83892960) at __mp_lock+0x1a3 __mp_lock_spin sys/kern/kern_lock.c:134 [inline] __mp_lock(ffffffff83892960) at __mp_lock+0x1a3 sys/kern/kern_lock.c:165 __mp_acquire_count(ffffffff83892960,1) at __mp_acquire_count+0x58 sys/kern/kern_lock.c:-1 sleep_finish(ffffffffffffffff,1) at sleep_finish+0x2d8 sys/kern/kern_synch.c:367 rw_do_enter_write(ffffffff83983380,0) at rw_do_enter_write+0x1dc sys/kern/kern_rwlock.c:298 vm_map_lock_ln(ffffffff83983298,0,0) at vm_map_lock_ln+0x12e sys/uvm/uvm_map.c:5168 uvm_map(ffffffff83983298,ffff80002a325a20,6000,0,ffffffffffffffff,0,2c16123701448f9e) at uvm_map+0x404 sys/uvm/uvm_map.c:1021 km_alloc(6000,ffffffff836fe5f0,ffffffff836c5588,ffffffff836c5600) at km_alloc+0x20d sys/uvm/uvm_km.c:746 uvm_uarea_alloc() at uvm_uarea_alloc+0x52 sys/uvm/uvm_glue.c:-1 fork1(ffff80002a2c2548,1,ffffffff8295fd60,0,ffff80002a325bb0,0) at fork1+0x315 sys/kern/kern_fork.c:395 syscall(ffff80002a325c60) at syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80002a325c60) at syscall+0xb17 sys/arch/amd64/amd64/trap.c:746 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x72f9c80811d0, count: -24 ddb{0}> machine ddbcpu 1 Stopped at savectx+0xae: movl $0,%gs:0x688 savectx() at savectx+0xae end of kernel end trace frame: 0x7c506afdb440, count: 14 ddb{1}> trace savectx() at savectx+0xae end of kernel end trace frame: 0x7c506afdb440, count: -1