panic: trap type 6, code=0, pc=ffffffff8163e168 Starting stack trace... panic(ffffffff834f0dab) at panic+0x1d0 sys/kern/subr_prf.c:229 kerntrap(ffff80003c3e9a50) at kerntrap+0x30b alltraps_kern_meltdown() at alltraps_kern_meltdown+0x7b dovutimens(ffff80003c4a3790,fffff0805f1aa968,ffff80003c3e9c10) at dovutimens+0x368 sys/kern/vfs_syscalls.c:2690 sys_futimens(ffff80003c4a3790,ffff80003c3e9d60,ffff80003c3e9cb0) at sys_futimens+0xb3 sys/kern/vfs_syscalls.c:2766 syscall(ffff80003c3e9d60) at syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80003c3e9d60) at syscall+0xb17 sys/arch/amd64/amd64/trap.c:783 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7afcbcd7420, count: 250 End of stack trace. WARNING: SPL NOT LOWERED ON SYSCALL 83 1733599424 EXIT 0 4 Stopped at savectx+0xae: movl $0,%gs:0x688 TID PID UID PRFLAGS PFLAGS CPU COMMAND *293742 71944 0 0 0 1 syz-executor 168687 73528 0 0x14000 0x200 0 softnet0 savectx() at savectx+0xae end of kernel end trace frame: 0x73878a8c7440, 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(0xfffff0807056dd80, 0x98, 0, 1) -> e ddb{1}> trace savectx() at savectx+0xae end of kernel end trace frame: 0x73878a8c7440, count: -1 ddb{1}> show registers rdi 0 rsi 0 rbp 0xffff80003c3e3c40 rbx 0 rdx 0 rcx 0xffff80003c4a3a28 rax 0x3b r8 0xffff80003c3e3b70 r9 0x1 r10 0xcbf8909f41e815d5 r11 0x528de7cc28b7b40f r12 0 r13 0 r14 0xffff80003c4a3a28 r15 0 rip 0xffffffff816673ee savectx+0xae cs 0x8 rflags 0x46 rsp 0xffff80003c3e3bc0 ss 0x10 savectx+0xae: movl $0,%gs:0x688 ddb{1}> show proc PROC (syz-executor) tid=293742 pid=71944 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=0xffff80003c4a2fc8,0xffff80003c4a37a0 process=0xffff80003c4666a8 user=0xffff80003c3de000, vmspace=0xfffff0807056dd80 estcpu=36, cpticks=1, pctcpu=0.0, user=0, sys=1, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND *71944 293742 35351 0 7 0 syz-executor 71944 368927 35351 0 3 0x4000000 sbar syz-executor 29408 365748 92067 0 2 0 syz-executor 29408 323106 92067 0 3 0x4000080 fsleep syz-executor 81839 218557 80064 0 2 0 syz-executor 81839 327379 80064 0 3 0x4000080 piperd syz-executor 99303 306882 32633 0 2 0 syz-executor 99303 331238 32633 0 3 0x4000080 fsleep syz-executor 88504 37632 61178 0 2 0 syz-executor 88504 521616 61178 0 3 0x4000080 fsleep syz-executor 88504 41802 61178 0 3 0x4000080 fsleep syz-executor 52840 27568 2019 0 3 0x80 nanoslp syz-executor 52840 274746 2019 0 3 0x4000080 fsleep syz-executor 52840 266579 2019 0 3 0x4000080 ttyout syz-executor 35257 518380 72843 0 3 0x80 nanoslp syz-executor 35257 391163 72843 0 3 0x4000080 msgwait syz-executor 35257 240576 72843 0 3 0x4000080 fsleep syz-executor 6728 490983 54385 0 3 0x90 nanoslp syz-executor 6728 491984 54385 0 3 0x4000090 fsleep syz-executor 6728 64268 54385 0 3 0x4000090 pipewr syz-executor 40299 472481 0 0 3 0x14200 acct acct 39296 359941 0 0 3 0x14280 nfsidl nfsio 19093 3707 0 0 3 0x14280 nfsidl nfsio 52666 338983 0 0 3 0x14280 nfsidl nfsio 66379 186472 0 0 3 0x14280 nfsidl nfsio 9358 37056 0 0 3 0x14280 nfsidl nfsio 73145 476207 0 0 3 0x14280 nfsidl nfsio 29049 145673 0 0 3 0x14280 nfsidl nfsio 54690 16288 0 0 3 0x14280 nfsidl nfsio 24749 135251 0 0 3 0x14280 nfsidl nfsio 21850 455591 0 0 3 0x14280 nfsidl nfsio 74739 245676 0 0 3 0x14280 nfsidl nfsio 95573 458171 0 0 3 0x14280 nfsidl nfsio 87036 171830 0 0 3 0x14280 nfsidl nfsio 37909 523669 0 0 3 0x14280 nfsidl nfsio 78732 57417 0 0 3 0x14280 nfsidl nfsio 47110 177045 0 0 3 0x14280 nfsidl nfsio 65434 18232 0 0 3 0x14280 nfsidl nfsio 93253 96341 0 0 3 0x14280 nfsidl nfsio 69229 317911 0 0 3 0x14280 nfsidl nfsio 46920 404000 0 0 3 0x14280 nfsidl nfsio 32633 404162 49570 0 3 0x82 nanoslp syz-executor 35351 165196 49570 0 3 0x82 nanoslp syz-executor 2019 135040 49570 0 2 0x2 syz-executor 72843 449303 49570 0 3 0x82 nanoslp syz-executor 80064 488366 49570 0 2 0x2 syz-executor 54385 500735 49570 0 3 0x82 nanoslp syz-executor 61178 374357 49570 0 3 0x82 nanoslp syz-executor 92067 112667 49570 0 3 0x82 nanoslp syz-executor 49570 402048 1 0 2 0x2 syz-executor 65546 150159 0 0 3 0x14200 bored smr 79514 252191 0 0 2 0x14200 zerothread 63935 460309 0 0 3 0x14200 aiodoned aiodoned 85690 139499 0 0 3 0x14200 syncer update 30377 427724 0 0 3 0x14200 cleaner cleaner 4925 289528 0 0 3 0x14200 reaper reaper 28433 468479 0 0 3 0x14200 pgdaemon pagedaemon 47390 447243 0 0 3 0x14200 bored viomb 77475 472682 0 0 3 0x40014200 acpi0 acpi0 68484 322929 0 0 3 0x40014200 idle1 88713 65995 0 0 3 0x14200 bored softnet1 73528 168687 0 0 7 0x14200 softnet0 1610 472178 0 0 3 0x14200 smrbar systqmp 92320 459236 0 0 3 0x14200 bored systq 18915 73288 0 0 3 0x14200 tmoslp softclockmp 931 330310 0 0 3 0x40014200 tmoslp softclock 40511 193822 0 0 3 0x40014200 idle0 1 35695 0 0 3 0x80082 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{1}> show all locks Process 71944 (syz-executor) thread 0xffff80003c4a3790 (368927) exclusive kernel_lock &kernel_lock r = 0 (0xffffffff83a9bb80) #0 witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline] #0 witness_lock+0x5f1 sys/kern/subr_witness.c:1160 #1 syscall+0xaf4 mi_syscall sys/sys/syscall_mi.h:175 [inline] #1 syscall+0xaf4 sys/arch/amd64/amd64/trap.c:783 #2 Xsyscall+0x128 Process 49570 (syz-executor) thread 0xffff800045ffdc90 (402048) shared rwlock pf_state_lock r = 0 (0xffffffff8398d990) #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_read+0x3e8 sys/kern/kern_rwlock.c:413 #2 pf_test+0x1bc4 sys/net/pf.c:8492 #3 ip_output+0xd6b sys/netinet/ip_output.c:401 #4 tcp_output+0x36e3 sys/netinet/tcp_output.c:1070 #5 tcp_rcvd+0x10d sys/netinet/tcp_usrreq.c:824 #6 soreceive+0x1d35 sys/kern/uipc_socket.c:1230 #7 soo_read+0x60 sys/kern/sys_socket.c:67 #8 dofilereadv+0x25a sys/kern/sys_generic.c:252 #9 sys_read+0xa2 sys/kern/sys_generic.c:172 #10 syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline] #10 syscall+0xbd4 sys/arch/amd64/amd64/trap.c:783 #11 Xsyscall+0x128 exclusive rwlock inet46 r = 0 (0xffff8000015aa030) #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 soreceive+0x1d19 pru_rcvd sys/sys/protosw.h:-1 [inline] #2 soreceive+0x1d19 sys/kern/uipc_socket.c:1229 #3 soo_read+0x60 sys/kern/sys_socket.c:67 #4 dofilereadv+0x25a sys/kern/sys_generic.c:252 #5 sys_read+0xa2 sys/kern/sys_generic.c:172 #6 syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline] #6 syscall+0xbd4 sys/arch/amd64/amd64/trap.c:783 #7 Xsyscall+0x128 shared rwlock netlock r = 0 (0xffffffff83980490) #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_read+0x3e8 sys/kern/kern_rwlock.c:413 #2 solock_shared+0x6e sys/kern/uipc_socket2.c:343 #3 soreceive+0x1d19 pru_rcvd sys/sys/protosw.h:-1 [inline] #3 soreceive+0x1d19 sys/kern/uipc_socket.c:1229 #4 soo_read+0x60 sys/kern/sys_socket.c:67 #5 dofilereadv+0x25a sys/kern/sys_generic.c:252 #6 sys_read+0xa2 sys/kern/sys_generic.c:172 #7 syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline] #7 syscall+0xbd4 sys/arch/amd64/amd64/trap.c:783 #8 Xsyscall+0x128 exclusive rwlock sbufrcv r = 0 (0xffff8000015aa100) #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 sblock+0xb6 sys/kern/uipc_socket2.c:536 #3 soreceive+0x27d sys/kern/uipc_socket.c:890 #4 soo_read+0x60 sys/kern/sys_socket.c:67 #5 dofilereadv+0x25a sys/kern/sys_generic.c:252 #6 sys_read+0xa2 sys/kern/sys_generic.c:172 #7 syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline] #7 syscall+0xbd4 sys/arch/amd64/amd64/trap.c:783 #8 Xsyscall+0x128 Process 1610 (systqmp) thread 0xffff800045ffe7c8 (472178) shared rwlock systqmp r = 0 (0xffffffff83981ef8) #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 11084 12019K 12302K 166960K 12678 0 pcb 17 15K 17K 166960K 161 0 rtable 196 9K 13K 166960K 556 0 pf 42 19K 28K 166960K 185 0 ifaddr 35 5K 8K 166960K 73 0 ifgroup 55 2K 2K 166960K 116 0 sysctl 3 1K 9K 166960K 11 0 counters 70 37K 37K 166960K 122 0 ioctlops 0 0K 4K 166960K 1687 0 iov 0 0K 16K 166960K 31 0 mount 1 1K 1K 166960K 1 0 log 0 0K 0K 166960K 4 0 vnodes 1385 87K 87K 166960K 2123 0 UFS quota 1 32K 32K 166960K 1 0 UFS mount 5 36K 36K 166960K 5 0 shm 2 1K 9K 166960K 13 0 VM map 2 1K 1K 166960K 2 0 sem 12 0K 0K 166960K 35 0 dirhash 12 2K 2K 166960K 15 0 ACPI 1734 201K 291K 166960K 11964 0 file desc 17 65K 93K 166960K 759 0 sigio 0 0K 0K 166960K 14 0 proc 12 17K 180K 166960K 609 0 subproc 72 4K 4K 166960K 73 0 NFS srvsock 1 0K 0K 166960K 1 0 NFS daemon 1 16K 16K 166960K 1 0 ip_moptions 0 0K 0K 166960K 56 0 in_multi 73 5K 7K 166960K 116 0 ether_multi 1 0K 0K 166960K 6 0 mrt 1 0K 0K 166960K 24 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 449 0 fusefs mount 1 32K 32K 166960K 1 0 pfkey data 0 0K 0K 166960K 1 0 tdb 3 0K 0K 166960K 3 0 VM swap 8 62K 64K 166960K 10 0 UVM amap 143 83K 192K 166960K 8975 0 UVM aobj 73 3K 3K 166960K 73 0 pinsyscall 18 36K 106K 166960K 1925 0 memdesc 1 4K 4K 166960K 1 0 crypto data 1 1K 1K 166960K 1 0 ip6_options 2 0K 0K 166960K 32 0 NDP 12 0K 1K 166960K 48 0 temp 61 9124K 9167K 166960K 34775 0 kqueue 1 2K 30K 166960K 157 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 28 0 0 1 0 1 1 0 8 0 rtpcb 120 85 0 85 1 0 1 1 0 8 1 rtentry 176 124 0 47 6 0 6 6 0 8 0 unpcb 144 520 0 518 4 2 2 4 0 8 1 syncache 336 7 0 7 2 2 0 1 0 8 0 tcpcb 736 307 0 305 13 0 13 13 0 8 12 arp 136 19 0 4 1 0 1 1 0 8 0 inpcb 328 901 0 864 18 3 15 15 0 8 11 nd6 152 31 0 10 2 0 2 2 0 8 0 pkpcb 40 5 0 5 1 0 1 1 0 8 1 kcovpl 48 8 0 0 1 0 1 1 0 8 0 ppxss 1192 18 0 18 2 1 1 1 0 8 1 pppxif 1576 3 0 3 1 1 0 1 0 8 0 pfstscr 40 12 0 8 1 0 1 1 0 8 0 pffrag 232 10 0 6 1 0 1 1 0 482 0 pffrnode 88 9 0 5 1 0 1 1 0 8 0 pffrent 40 16 0 12 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 9 1 0 1 1 0 8 0 pfsrclim 320 4 0 3 2 1 1 1 0 8 0 pfstlim 224 1 0 1 1 1 0 1 0 8 0 pfanchor 1288 13 0 3 1 0 1 1 0 8 0 pftag 88 3 0 1 1 0 1 1 0 8 0 pfstitem 24 85 0 19 1 0 1 1 0 8 0 pfstkey 128 91 0 24 3 0 3 3 0 8 0 pfstate 448 84 0 21 8 0 8 8 0 8 0 pfrule 1360 31 0 25 2 1 1 2 0 8 0 art_heap8 4096 2 0 0 2 0 2 2 0 8 0 art_heap4 256 569 0 161 31 1 30 31 0 8 3 art_table 40 571 0 161 5 0 5 5 0 8 0 art_node 32 124 0 55 1 0 1 1 0 8 0 sysvmsgpl 40 13 0 5 1 0 1 1 0 8 0 semapl 72 32 0 22 1 0 1 1 0 8 0 shmpl 112 70 0 0 2 0 2 2 0 8 0 dirhash 1024 19 0 2 3 0 3 3 0 8 0 dino2pl 256 2837 0 1372 93 0 93 93 0 8 0 ffsino 296 2837 0 1372 114 0 114 114 0 8 0 nchpl 144 3947 0 2242 64 0 64 64 0 8 0 rtmask 32 3 0 3 1 1 0 1 0 8 0 vnodes 216 3351 0 0 187 0 187 187 0 8 0 namei 1024 13814 0 13814 2 0 2 2 0 8 2 percpumem 16 77 0 26 1 0 1 1 0 8 0 pfiaddrpl 120 3 0 3 1 0 1 1 0 8 1 kstatmem 264 69 0 40 4 1 3 3 0 8 0 scsiplug 72 4 0 4 2 1 1 1 0 8 1 scxspl 216 14750 0 14749 9 8 1 6 1 8 0 plimitpl 152 105 0 95 1 0 1 1 0 8 0 sigapl 424 1099 0 1043 8 0 8 8 0 8 0 knotepl 120 329 0 0 10 0 10 10 0 8 0 kqueuepl 224 336 0 301 5 0 5 5 0 8 2 pipepl 344 182 0 153 3 0 3 3 0 8 0 fdescpl 528 1062 0 1043 3 0 3 3 0 8 0 filepl 160 7114 0 6882 19 3 16 16 0 8 5 lockfpl 104 403 0 402 1 0 1 1 0 8 0 lockfspl 48 171 0 170 1 0 1 1 0 8 0 sessionpl 144 90 0 88 1 0 1 1 0 8 0 pgrppl 48 110 0 100 1 0 1 1 0 8 0 ucredpl 104 1629 0 1625 1 0 1 1 0 8 0 zombiepl 144 1043 0 1043 2 1 1 1 0 8 1 processpl 1232 1099 0 1043 6 0 6 6 0 8 0 procpl 664 2206 0 2138 9 1 8 8 0 8 0 sockpl 752 1590 0 1551 24 6 18 18 0 8 13 mcl64k 65536 5 0 0 1 0 1 1 0 8 0 mcl16k 16384 2 0 0 1 0 1 1 0 8 0 mcl12k 12288 1 0 0 1 0 1 1 0 8 0 mcl9k128 9344 1 0 0 1 0 1 1 0 8 0 mcl8k 8192 2 0 0 1 0 1 1 0 8 0 mcl4k 4096 120 0 0 15 0 15 15 0 8 0 mcl2k2 2112 2 0 0 1 0 1 1 0 8 0 mcl2k 2048 24 0 0 3 0 3 3 0 8 0 mextrefs 64 30 0 0 1 0 1 1 0 8 0 mtagpl 96 2 0 0 1 0 1 1 0 8 0 mbufpl 256 237 0 0 15 0 15 15 0 8 0 bufpl 272 5391 0 111 352 0 352 352 0 8 0 anonpl 32 8112 0 0 66 0 66 66 0 247 0 amapchunkpl 152 28512 0 28124 34 7 27 28 0 158 12 amappl16 200 2835 0 2805 22 11 11 15 0 8 8 amappl15 192 5 0 5 1 1 0 1 0 8 0 amappl14 184 429 0 428 1 0 1 1 0 8 0 amappl13 176 124 0 124 1 0 1 1 0 8 1 amappl12 168 1315 0 1297 2 0 2 2 0 8 0 amappl11 160 3 0 3 1 1 0 1 0 8 0 amappl10 152 62 0 62 1 0 1 1 0 8 1 amappl9 144 302 0 302 1 1 0 1 0 8 0 amappl8 136 125 0 125 1 0 1 1 0 8 1 amappl7 128 151 0 149 1 0 1 1 0 8 0 amappl6 120 160 0 159 1 0 1 1 0 8 0 amappl5 112 135 0 134 1 0 1 1 0 8 0 amappl4 104 328 0 325 1 0 1 1 0 8 0 amappl3 96 5762 0 5676 5 1 4 4 0 8 0 amappl2 88 558 0 550 2 0 2 2 0 8 0 amappl1 80 13536 0 13442 18 6 12 16 0 8 8 amappl 88 8076 0 7947 6 1 5 5 0 92 0 uvmvnodes 80 122 0 0 3 0 3 3 0 8 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 7 0 7 2 2 0 1 0 8 0 dma128 128 254 0 254 2 2 0 1 0 8 0 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 72 0 0 2 0 2 2 0 8 0 uaddrrnd 24 1062 0 1043 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 1062 0 1043 1 0 1 1 0 8 0 vmmpekpl 168 10637 0 10599 2 0 2 2 0 8 0 vmmpepl 168 75328 0 74461 108 12 96 98 0 357 56 vmsppl 488 1061 0 1043 6 2 4 5 0 8 0 rwobjpl 80 22706 0 22208 32 4 28 28 0 8 4 pdppl 4096 2131 0 2086 109 64 45 87 0 8 0 pvpl 32 15398 0 0 125 1 124 124 0 265 0 pmappl 256 1061 0 1043 3 0 3 3 0 8 0 extentpl 40 46 0 28 1 0 1 1 0 8 0 phpool 112 661 0 72 17 0 17 17 0 8 0 ddb{1}> machine ddbcpu 0 Stopped at x86_ipi_db+0x27: addq $0x8,%rsp x86_ipi_db(ffffffff838eeff0) 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_release_all(ffff80000002c000) at __mp_release_all+0xef sys/kern/kern_lock.c:223 taskq_next_work(ffff80000002c000,ffff80002a1d0018) at taskq_next_work+0x8e sys/kern/kern_task.c:399 taskq_thread(ffff80000002c000) at taskq_thread+0x1d5 sys/kern/kern_task.c:439 end trace frame: 0x0, count: 9 ddb{0}> trace x86_ipi_db(ffffffff838eeff0) 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_release_all(ffff80000002c000) at __mp_release_all+0xef sys/kern/kern_lock.c:223 taskq_next_work(ffff80000002c000,ffff80002a1d0018) at taskq_next_work+0x8e sys/kern/kern_task.c:399 taskq_thread(ffff80000002c000) at taskq_thread+0x1d5 sys/kern/kern_task.c:439 end trace frame: 0x0, count: -6 ddb{0}> machine ddbcpu 1 Stopped at savectx+0xae: movl $0,%gs:0x688 savectx() at savectx+0xae end of kernel end trace frame: 0x73878a8c7440, count: 14 ddb{1}> trace savectx() at savectx+0xae end of kernel end trace frame: 0x73878a8c7440, count: -1 ddb{1}>