uvm_fault(0xfffffd805f56f028, 0x0, 0, 1) -> e fatal page fault in supervisor mode trap type 6 code 0 rip ffffffff81acc2e8 cs 8 rflags 10207 cr2 0 cpl 0 rsp ffff80003c444bf0 gsbase 0xffff8000299edff0 kgsbase 0x0 panic: trap type 6, code=0, pc=ffffffff81acc2e8 Starting stack trace... panic(ffffffff833a52af) at panic+0x1d0 sys/kern/subr_prf.c:229 kerntrap(ffff80003c444b40) at kerntrap+0x30b alltraps_kern_meltdown() at alltraps_kern_meltdown+0x7b dt_ioctl_record_stop(ffff800001487000) at dt_ioctl_record_stop+0x108 sys/dev/dt/dt_dev.c:586 dtclose(11e5f,81,2000,ffff80003c4f34f8) at dtclose+0x109 dt_pcb_purge sys/dev/dt/dt_dev.c:-1 [inline] dtclose(11e5f,81,2000,ffff80003c4f34f8) at dtclose+0x109 sys/dev/dt/dt_dev.c:232 spec_close(ffff80003c444cf0) at spec_close+0x466 sys/kern/spec_vnops.c:-1 VOP_CLOSE(fffffd805c1db028,81,fffffd80097fb138,ffff80003c4f34f8) at VOP_CLOSE+0x132 sys/kern/vfs_vops.c:156 vn_closefile(fffffd80660e6238,ffff80003c4f34f8) at vn_closefile+0x12b vn_close sys/kern/vfs_vnops.c:292 [inline] vn_closefile(fffffd80660e6238,ffff80003c4f34f8) at vn_closefile+0x12b sys/kern/vfs_vnops.c:615 fdrop(fffffd80660e6238,ffff80003c4f34f8) at fdrop+0x121 sys/kern/kern_descrip.c:1280 closef(fffffd80660e6238,ffff80003c4f34f8) at closef+0x192 sys/kern/kern_descrip.c:1264 fdfree(ffff80003c4f34f8) at fdfree+0x116 sys/kern/kern_descrip.c:1195 exit1(ffff80003c4f34f8,0,0,1) at exit1+0x576 sys/kern/kern_exit.c:215 sys_exit(ffff80003c4f34f8,ffff80003c445060,ffff80003c444fb0) at sys_exit+0x1a sys/kern/kern_exit.c:-1 syscall(ffff80003c445060) at syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80003c445060) at syscall+0xb17 sys/arch/amd64/amd64/trap.c:746 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7d881f0a8180, count: 242 End of stack trace. W ARNING: SPL NOT LOWERED ON SYSCALL 83 738299264 EXIT 0 4 Stopped at savectx+0xae: movl $0,%gs:0x688 TID PID UID PRFLAGS PFLAGS CPU COMMAND *161296 1490 0 0 0x4000000 1 syz-executor 75767 84266 0 0x100003 0x80 0 getty savectx() at savectx+0xae end of kernel end trace frame: 0xf0bd1ebb190, 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(0xfffffd805f56f028, 0x0, 0, 1) -> e ddb{1}> trace savectx() at savectx+0xae end of kernel end trace frame: 0xf0bd1ebb190, count: -1 ddb{1}> show registers rdi 0 rsi 0 rbp 0xffff800034815360 rbx 0 rdx 0xffff80000144f580 rcx 0xffff800031809ca8 rax 0x3a r8 0xffff800034815290 r9 0x1 r10 0x6a24090bfb0a3bb5 r11 0x3d030ace8144c013 r12 0 r13 0 r14 0xffff800031809ca8 r15 0 rip 0xffffffff817e23ee savectx+0xae cs 0x8 rflags 0x46 rsp 0xffff8000348152e0 ss 0x10 savectx+0xae: movl $0,%gs:0x688 ddb{1}> show proc PROC (syz-executor) tid=161296 pid=1490 tcnt=2 stat=onproc flags process=0 proc=4000000 runpri=32, usrpri=50, slppri=32, nice=20 wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0 forw=0xffffffffffffffff, list=0xffff8000318087e8,0xffffffff8391e108 process=0xffff80003c4c4028 user=0xffff800034810000, vmspace=0xfffffd805f56f9b0 estcpu=36, cpticks=1, pctcpu=0.0, user=0, sys=1, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 1490 271264 68545 0 2 0 syz-executor * 1490 161296 68545 0 7 0x4000000 syz-executor 83669 34338 9501 0 2 0 syz-executor 83669 63561 9501 0 3 0x4000080 sbwait syz-executor 5201 422926 8041 0 2 0xc80 syz-executor 5201 399929 8041 0 3 0x4000080 lockf syz-executor 5201 189496 8041 0 3 0x4000080 fsleep syz-executor 86026 94193 53152 0 2 0xc80 syz-executor 86026 384281 53152 0 3 0x4000080 ttyout syz-executor 86026 485993 53152 0 3 0x4000080 fsleep syz-executor 99797 124136 98649 0 2 0 syz-executor 99797 106829 98649 0 3 0x4000080 fifow syz-executor 99797 170814 98649 0 3 0x4000080 fsleep syz-executor 9803 345825 21016 0 2 0 syz-executor 9803 241085 21016 0 3 0x4000080 kqsel syz-executor 9803 297857 21016 0 3 0x4000080 fsleep syz-executor 34035 164575 0 0 3 0x14200 acct acct 85854 62670 0 0 3 0x14200 bored sosplice 53152 498079 34522 0 2 0xc82 syz-executor 8041 241857 34522 0 2 0xc82 syz-executor 9501 220894 34522 0 2 0xc82 syz-executor 68545 41384 34522 0 2 0xc82 syz-executor 98649 123912 34522 0 2 0xc82 syz-executor 39986 33681 34522 0 2 0x2 syz-executor 52113 76416 34522 0 2 0xc82 syz-executor 21016 511832 34522 0 2 0x2 syz-executor 34522 48820 41647 0 3 0x82 kqread syz-executor 41647 258839 35792 0 3 0x10008a sigsusp ksh 35792 162295 37516 0 3 0x98 kqread sshd-session 37516 347541 550 0 3 0x92 kqread sshd-session 84266 75767 1 0 7 0x100083 getty 550 178851 1 0 3 0x88 kqread sshd 60990 429949 79640 74 3 0x1100092 bpf pflogd 79640 6697 1 0 3 0x80 sbwait pflogd 36820 189017 62070 73 3 0x1100090 kqread syslogd 62070 12154 1 0 3 0x100082 sbwait syslogd 64787 447482 1 0 3 0x100080 kqread resolvd 64840 130212 30245 77 3 0x100092 kqread dhcpleased 26850 293874 30245 77 3 0x100092 kqread dhcpleased 30245 225084 1 0 3 0x80 kqread dhcpleased 78507 470555 0 0 3 0x14200 bored smr 39258 476224 0 0 3 0x14200 pgzero zerothread 3018 26444 0 0 3 0x14200 aiodoned aiodoned 50411 2874 0 0 3 0x14200 syncer update 52456 509977 0 0 3 0x14200 cleaner cleaner 55828 213483 0 0 3 0x14200 reaper reaper 21035 518062 0 0 3 0x14200 pgdaemon pagedaemon 85541 368538 0 0 3 0x14200 bored viomb 96736 418502 0 0 3 0x40014200 acpi0 acpi0 59615 84909 0 0 3 0x40014200 idle1 3489 247731 0 0 3 0x14200 bored softnet7 33634 191352 0 0 3 0x14200 bored softnet6 38468 271971 0 0 3 0x14200 bored softnet5 79169 200513 0 0 3 0x14200 bored softnet4 99511 357951 0 0 3 0x14200 bored softnet3 65511 311581 0 0 3 0x14200 bored softnet2 41825 158040 0 0 3 0x14200 bored softnet1 85353 386272 0 0 2 0x14200 softnet0 34830 333241 0 0 2 0x14200 systqmp 53150 214981 0 0 3 0x14200 bored systq 3154 223449 0 0 3 0x14200 tmoslp softclockmp 20241 399150 0 0 3 0x40014200 tmoslp softclock 85464 242897 0 0 3 0x40014200 idle0 1 452211 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 10243 11101K 11798K 166960K 11941 0 pcb 17 14K 15K 166960K 167 0 rtable 130 8K 8K 166960K 441 0 pf 39 18K 21K 166960K 120 0 ifaddr 31 4K 7K 166960K 86 0 ifgroup 63 2K 3K 166960K 144 0 sysctl 3 1K 9K 166960K 11 0 counters 72 37K 38K 166960K 156 0 ioctlops 0 0K 4K 166960K 1707 0 iov 1 4K 28K 166960K 48 0 mount 1 1K 1K 166960K 1 0 log 0 0K 0K 166960K 4 0 vnodes 1368 86K 86K 166960K 1931 0 UFS quota 1 32K 32K 166960K 1 0 UFS mount 5 36K 36K 166960K 5 0 shm 2 1K 9K 166960K 16 0 VM map 2 1K 1K 166960K 2 0 sem 16 5K 5K 166960K 30 0 dirhash 12 2K 2K 166960K 27 0 ACPI 1692 195K 286K 166960K 12470 0 file desc 18 65K 89K 166960K 865 0 sigio 2 0K 0K 166960K 16 0 proc 72 115K 180K 166960K 618 0 subproc 72 4K 4K 166960K 74 0 NFS srvsock 1 0K 0K 166960K 1 0 NFS daemon 1 16K 16K 166960K 1 0 ip_moptions 0 0K 0K 166960K 302 0 in_multi 49 3K 7K 166960K 138 0 ether_multi 1 0K 0K 166960K 7 0 mrt 1 0K 0K 166960K 7 0 ISOFS mount 1 32K 32K 166960K 1 0 MSDOSFS mount 1 16K 16K 166960K 1 0 ttys 85 387K 387K 166960K 85 0 exec 0 0K 1K 166960K 504 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 250 159K 174K 166960K 9584 0 UVM aobj 22 2K 2K 166960K 24 0 pinsyscall 43 86K 102K 166960K 1958 0 memdesc 1 4K 4K 166960K 1 0 crypto data 1 1K 1K 166960K 1 0 ip6_options 0 0K 0K 166960K 52 0 NDP 14 0K 2K 166960K 58 0 temp 78 8652K 8718K 166960K 40440 0 kqueue 13 20K 33K 166960K 190 0 SYN cache 2 16K 16K 166960K 2 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 120 123 0 120 2 0 2 2 0 8 1 rtentry 176 112 0 70 5 0 5 5 0 8 0 unpcb 144 978 0 957 9 5 4 6 0 8 2 syncache 336 8 0 8 2 1 1 1 0 8 1 tcpqe 32 1 0 1 1 0 1 1 0 8 1 tcpcb 736 343 0 337 8 6 2 7 0 8 0 arp 128 11 0 5 1 0 1 1 0 8 0 inpcb 328 1097 0 1088 10 3 7 7 0 8 5 nd6 144 18 0 11 1 0 1 1 0 8 0 pkpcb 40 10 0 10 1 0 1 1 0 8 1 kcovpl 48 8 0 0 1 0 1 1 0 8 0 mppekey 1024 4 0 4 2 1 1 1 0 8 1 ppxss 1192 32 0 32 1 0 1 1 0 8 1 pppxif 1504 4 0 4 2 1 1 1 0 8 1 pffrag 232 7 0 4 1 0 1 1 0 482 0 pffrnode 88 7 0 4 1 0 1 1 0 8 0 pffrent 40 13 0 10 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 2 0 2 2 1 1 1 0 8 1 pfanchor 1288 1 0 0 1 0 1 1 0 8 0 pfstitem 24 71 0 10 1 0 1 1 0 8 0 pfstkey 128 71 0 10 2 0 2 2 0 8 0 pfstate 384 70 0 10 6 0 6 6 0 8 0 pfrule 1344 24 0 18 2 1 1 2 0 8 0 rttmr 136 2 0 2 2 1 1 1 0 8 1 art_heap8 4096 2 0 0 2 0 2 2 0 8 0 art_heap4 256 566 0 331 28 8 20 28 0 8 3 art_table 40 568 0 331 5 0 5 5 0 8 0 art_node 32 112 0 77 1 0 1 1 0 8 0 sysvmsgpl 40 1 0 1 1 1 0 1 0 8 0 semapl 112 23 0 9 1 0 1 1 0 8 0 shmpl 112 21 0 2 1 0 1 1 0 8 0 dirhash 1024 28 0 11 3 0 3 3 0 8 0 dino2pl 256 3062 0 1557 95 0 95 95 0 8 0 ffsino 296 3062 0 1557 117 0 117 117 0 8 0 nchpl 144 4292 0 2600 64 0 64 64 0 8 0 rtmask 32 2 0 2 1 1 0 1 0 8 0 uvmvnodes 80 3383 0 0 70 0 70 70 0 8 0 vnodes 216 3383 0 0 188 0 188 188 0 8 0 namei 1024 14223 0 14223 3 2 1 2 0 8 1 percpumem 16 93 0 42 1 0 1 1 0 8 0 kstatmem 264 90 0 54 3 0 3 3 0 8 0 scsiplug 72 4 0 4 1 0 1 1 0 8 1 scxspl 216 22773 0 22773 10 4 6 8 1 8 6 plimitpl 152 329 0 309 1 0 1 1 0 8 0 sigapl 424 1192 0 1136 9 0 9 9 0 8 2 knotepl 120 651 0 0 20 0 20 20 0 8 0 kqueuepl 224 390 0 379 5 4 1 5 0 8 0 pipepl 344 190 0 160 4 0 4 4 0 8 1 fdescpl 528 1148 0 1116 3 0 3 3 0 8 0 filepl 160 7408 0 7168 19 5 14 18 0 8 3 lockfpl 104 412 0 406 2 1 1 2 0 8 0 lockfspl 48 124 0 120 1 0 1 1 0 8 0 sessionpl 144 25 0 16 1 0 1 1 0 8 0 pgrppl 48 44 0 27 1 0 1 1 0 8 0 ucredpl 104 1129 0 1115 1 0 1 1 0 8 0 zombiepl 144 1138 0 1136 1 0 1 1 0 8 0 processpl 1232 1192 0 1136 6 0 6 6 0 8 0 procpl 664 2477 0 2411 9 1 8 9 0 8 2 sosppl 168 4 0 4 2 2 0 1 0 8 0 sockpl 752 2232 0 2199 27 15 12 23 0 8 8 mcl64k 65536 3 0 0 1 0 1 1 0 8 0 mcl16k 16384 2 0 0 1 0 1 1 0 8 0 mcl8k 8192 4 0 0 1 0 1 1 0 8 0 mcl4k 4096 130 0 0 17 0 17 17 0 8 0 mcl2k 2048 51 0 0 7 1 6 7 0 8 0 mtagpl 96 5 0 0 1 0 1 1 0 8 0 mbufpl 256 214 0 0 13 0 13 13 0 8 0 bufpl 280 9008 0 2865 439 0 439 439 0 8 0 anonpl 32 10704 0 0 87 0 87 87 0 246 0 amapchunkpl 152 31713 0 31178 33 3 30 30 0 158 8 amappl16 200 4308 0 4270 29 13 16 24 0 8 8 amappl15 192 4 0 4 1 1 0 1 0 8 0 amappl14 184 113 0 101 1 0 1 1 0 8 0 amappl13 176 6 0 6 2 1 1 1 0 8 1 amappl12 168 1793 0 1761 3 1 2 2 0 8 0 amappl11 160 52 0 38 1 0 1 1 0 8 0 amappl10 152 22 0 22 1 1 0 1 0 8 0 amappl9 144 253 0 253 1 1 0 1 0 8 0 amappl8 136 24 0 21 1 0 1 1 0 8 0 amappl7 128 110 0 97 1 0 1 1 0 8 0 amappl6 120 192 0 189 1 0 1 1 0 8 0 amappl5 112 134 0 124 1 0 1 1 0 8 0 amappl4 104 312 0 290 1 0 1 1 0 8 0 amappl3 96 5515 0 5410 4 1 3 3 0 8 0 amappl2 88 1400 0 1322 2 0 2 2 0 8 0 amappl1 80 11882 0 11269 15 0 15 15 0 8 0 amappl 88 8761 0 8583 5 0 5 5 0 92 0 dma65536 65536 1 0 1 1 0 1 1 0 8 1 dma4096 4096 1 0 1 1 1 0 1 0 8 0 dma1024 1024 1 0 0 1 0 1 1 0 8 0 dma512 512 1 0 1 1 0 1 1 0 8 1 dma256 256 6 0 6 1 1 0 1 0 8 0 dma128 128 254 0 254 2 1 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 19 0 18 1 0 1 1 0 8 0 aobjpl 72 23 0 2 1 0 1 1 0 8 0 uaddrrnd 24 1148 0 1116 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 1148 0 1116 1 0 1 1 0 8 0 vmmpekpl 168 11007 0 10965 3 0 3 3 0 8 0 vmmpepl 168 78655 0 76583 109 2 107 109 0 357 14 vmsppl 488 1147 0 1116 6 1 5 5 0 8 1 rwobjpl 80 26366 0 22001 91 1 90 90 0 8 0 pdppl 4096 2304 0 2232 106 34 72 84 0 8 0 pvpl 32 18646 0 0 151 0 151 151 0 265 0 pmappl 256 1147 0 1116 3 0 3 3 0 8 0 extentpl 40 45 0 27 1 0 1 1 0 8 0 phpool 112 297 0 55 8 0 8 8 0 8 0 ddb{1}> machine ddbcpu 0 Stopped at x86_ipi_db+0x27: addq $0x8,%rsp x86_ipi_db(ffffffff83837ff0) 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 __mp_lock(ffffffff838727a8) at __mp_lock+0x192 __mp_lock_spin sys/kern/kern_lock.c:134 [inline] __mp_lock(ffffffff838727a8) at __mp_lock+0x192 sys/kern/kern_lock.c:165 intr_handler(ffff80002a2e1050,ffff800000069c00) at intr_handler+0xe9 sys/arch/amd64/amd64/intr.c:559 Xintr_ioapic_edge16_untramp() at Xintr_ioapic_edge16_untramp+0x18f __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(ffffffff838727a8) at __mp_lock+0x1a3 __mp_lock_spin sys/kern/kern_lock.c:134 [inline] __mp_lock(ffffffff838727a8) at __mp_lock+0x1a3 sys/kern/kern_lock.c:165 __mp_acquire_count(ffffffff838727a8,1) 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 ttread(ffff800000afc200,ffff80002a2e1578,0) at ttread+0x7d3 ttysleep_nsec sys/kern/tty.c:2324 [inline] ttread(ffff800000afc200,ffff80002a2e1578,0) at ttread+0x7d3 ttysleep sys/kern/tty.c:2314 [inline] ttread(ffff800000afc200,ffff80002a2e1578,0) at ttread+0x7d3 sys/kern/tty.c:1587 spec_read(ffff80002a2e13d0) at spec_read+0x14b sys/kern/spec_vnops.c:215 VOP_READ(fffffd806f572968,ffff80002a2e1578,0,fffffd80097fbea0) at VOP_READ+0x101 sys/kern/vfs_vops.c:227 vn_read(fffffd806ef01968,ffff80002a2e1578,0) at vn_read+0x17b sys/kern/vfs_vnops.c:369 end trace frame: 0xffff80002a2e1560, count: 0 ddb{0}> trace x86_ipi_db(ffffffff83837ff0) 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 __mp_lock(ffffffff838727a8) at __mp_lock+0x192 __mp_lock_spin sys/kern/kern_lock.c:134 [inline] __mp_lock(ffffffff838727a8) at __mp_lock+0x192 sys/kern/kern_lock.c:165 intr_handler(ffff80002a2e1050,ffff800000069c00) at intr_handler+0xe9 sys/arch/amd64/amd64/intr.c:559 Xintr_ioapic_edge16_untramp() at Xintr_ioapic_edge16_untramp+0x18f __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(ffffffff838727a8) at __mp_lock+0x1a3 __mp_lock_spin sys/kern/kern_lock.c:134 [inline] __mp_lock(ffffffff838727a8) at __mp_lock+0x1a3 sys/kern/kern_lock.c:165 __mp_acquire_count(ffffffff838727a8,1) 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 ttread(ffff800000afc200,ffff80002a2e1578,0) at ttread+0x7d3 ttysleep_nsec sys/kern/tty.c:2324 [inline] ttread(ffff800000afc200,ffff80002a2e1578,0) at ttread+0x7d3 ttysleep sys/kern/tty.c:2314 [inline] ttread(ffff800000afc200,ffff80002a2e1578,0) at ttread+0x7d3 sys/kern/tty.c:1587 spec_read(ffff80002a2e13d0) at spec_read+0x14b sys/kern/spec_vnops.c:215 VOP_READ(fffffd806f572968,ffff80002a2e1578,0,fffffd80097fbea0) at VOP_READ+0x101 sys/kern/vfs_vops.c:227 vn_read(fffffd806ef01968,ffff80002a2e1578,0) at vn_read+0x17b sys/kern/vfs_vnops.c:369 dofilereadv(ffff80002a2b9770,0,ffff80002a2e1578,0,ffff80002a2e1630) at dofilereadv+0x25a sys/kern/sys_generic.c:252 sys_read(ffff80002a2b9770,ffff80002a2e16e0,ffff80002a2e1630) at sys_read+0xa2 sys/kern/sys_generic.c:172 syscall(ffff80002a2e16e0) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80002a2e16e0) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:746 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x714e88330950, count: -18 ddb{0}> machine ddbcpu 1 Stopped at savectx+0xae: movl $0,%gs:0x688 savectx() at savectx+0xae end of kernel end trace frame: 0xf0bd1ebb190, count: 14 ddb{1}> trace savectx() at savectx+0xae end of kernel end trace frame: 0xf0bd1ebb190, count: -1