*cpu0: uvm_fault(0xffffffff838d5f00, 0xffff8000014d504a, 0, 1) -> e ddb{1}> trace savectx() at savectx+0xae end of kernel end trace frame: 0x74738f87a800, count: -1 ddb{1}> show registers rdi 0 rsi 0 rbp 0xffff80003c45f530 rbx 0 rdx 0 rcx 0xffff80003c454550 rax 0x3c r8 0xffff80003c45f460 r9 0x1 r10 0xaf485a7c5f831604 r11 0xff6a75999be46de9 r12 0 r13 0 r14 0xffff80003c454550 r15 0 rip 0xffffffff81f083ee savectx+0xae cs 0x8 rflags 0x46 rsp 0xffff80003c45f4b0 ss 0x10 savectx+0xae: movl $0,%gs:0x680 ddb{1}> show proc PROC (syz-executor) tid=336295 pid=11088 tcnt=1 stat=onproc flags process=2 proc=0 runpri=32, usrpri=83, slppri=32, nice=20 wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0 forw=0xffffffffffffffff, list=0xffff80002a2baf80,0xffff80003c454d10 process=0xffff8000ffff4e00 user=0xffff80003c45a000, vmspace=0xfffffd805b664208 estcpu=33, cpticks=1, pctcpu=0.3, user=1, sys=4, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 62788 213858 13050 0 2 0 syz-executor 62788 47264 13050 0 7 0x4000000 syz-executor 72800 68692 3552 0 2 0 syz-executor 72800 488427 3552 0 3 0x4000080 fsleep syz-executor 33508 51368 93878 0 3 0x80 nanoslp syz-executor 33508 270805 93878 0 3 0x4000080 kqsel syz-executor 33508 311586 93878 0 3 0x4000080 fsleep syz-executor 69343 473363 51415 0 3 0x80 nanoslp syz-executor 69343 469328 51415 0 3 0x4000080 sbwait syz-executor 69343 26639 51415 0 3 0x4000080 fsleep syz-executor 69890 269157 11088 60929 3 0x90 nanoslp syz-executor 69890 378543 11088 60929 3 0x4000090 msgwait syz-executor 69890 442314 11088 60929 3 0x4000090 fsleep syz-executor *11088 336295 79905 0 7 0x2 syz-executor 53448 270623 1 0 3 0x100083 ttyin getty 93878 126892 79905 0 2 0x2 syz-executor 8371 465942 0 0 3 0x14200 acct acct 13050 125043 79905 0 3 0x82 nanoslp syz-executor 52864 399041 0 0 3 0x14200 bored sosplice 86658 211621 79905 0 2 0x10000082 syz-executor 3552 329563 79905 0 3 0x82 nanoslp syz-executor 16881 178797 79905 0 2 0x2 syz-executor 86530 118197 79905 0 2 0x2 syz-executor 51415 259958 79905 0 3 0x82 nanoslp syz-executor 79905 146627 37879 0 3 0x82 kqread syz-executor 37879 48724 80464 0 3 0x10008a sigsusp ksh 80464 38862 6470 0 3 0x98 kqread sshd-session 6470 29462 74021 0 3 0x92 kqread sshd-session 74021 207854 1 0 3 0x88 kqread sshd 56174 299924 80095 74 3 0x1100092 bpf pflogd 80095 109647 1 0 3 0x80 sbwait pflogd 61308 326783 94967 73 3 0x1100090 kqread syslogd 94967 421189 1 0 3 0x100082 sbwait syslogd 48420 379345 1 0 3 0x100080 kqread resolvd 47476 240182 92714 77 3 0x100092 kqread dhcpleased 51036 483443 92714 77 3 0x100092 kqread dhcpleased 92714 490207 1 0 3 0x80 kqread dhcpleased 10262 167063 0 0 2 0x40014200 smr 85666 147491 0 0 3 0x14200 pgzero zerothread 56012 106965 0 0 3 0x14200 aiodoned aiodoned 55794 286894 0 0 3 0x14200 syncer update 35427 435636 0 0 3 0x14200 cleaner cleaner 35298 480567 0 0 3 0x14200 reaper reaper 87684 478930 0 0 3 0x14200 pgdaemon pagedaemon 99482 38586 0 0 3 0x14200 bored viomb 46393 39004 0 0 3 0x40014200 acpi0 acpi0 2641 204590 0 0 3 0x40014200 idle1 35053 141476 0 0 3 0x14200 bored softnet3 25503 10119 0 0 3 0x14200 bored softnet2 29238 298612 0 0 3 0x14200 bored softnet1 53572 319900 0 0 3 0x14200 bored softnet0 470 67660 0 0 2 0x14200 systqmp 27156 328390 0 0 3 0x14200 bored systq 92918 442990 0 0 3 0x14200 tmoslp softclockmp 99475 42893 0 0 2 0x40014200 softclock 74849 211440 0 0 3 0x40014200 idle0 1 259170 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{1}> show all locks CPU 1: exclusive mutex /syzkaller/managers/multicore/kernel/sys/kern/vfs_subr.c:124 r = 0 (0xffffffff838111d8) #0 witness_lock+0x5bb stacktrace_save sys/sys/stacktrace.h:37 [inline] #0 witness_lock+0x5bb sys/kern/subr_witness.c:1160 #1 mtx_enter_try+0x178 sys/kern/kern_lock.c:-1 #2 mtx_enter+0x60 sys/kern/kern_lock.c:239 #3 vn_lock+0xbc sys/kern/vfs_vnops.c:573 #4 vget+0x2bd sys/kern/vfs_subr.c:694 #5 ktrwriteraw+0x172 sys/kern/kern_ktrace.c:688 #6 ktrsyscall+0x32b ktrwrite sys/kern/kern_ktrace.c:-1 [inline] #6 ktrsyscall+0x32b sys/kern/kern_ktrace.c:183 #7 syscall+0x2e6 mi_syscall sys/sys/syscall_mi.h:154 [inline] #7 syscall+0x2e6 sys/arch/amd64/amd64/trap.c:577 #8 Xsyscall+0x128 Process 62788 (syz-executor) thread 0xffff80003c455c60 (47264) exclusive rwlock netlock r = 0 (0xffffffff838ad130) #0 witness_lock+0x5bb stacktrace_save sys/sys/stacktrace.h:37 [inline] #0 witness_lock+0x5bb sys/kern/subr_witness.c:1160 #1 rw_do_enter_write+0x3ea sys/kern/kern_rwlock.c:316 #2 rtm_output+0x78c sys/net/rtsock.c:969 #3 route_output+0x9a1 sys/net/rtsock.c:878 #4 route_send+0xd7 sys/net/rtsock.c:342 #5 sosend+0x804 sys/kern/uipc_socket.c:-1 #6 sendit+0x721 sys/kern/uipc_syscalls.c:779 #7 sys_sendto+0x8d sys/kern/uipc_syscalls.c:557 #8 syscall+0xbc6 mi_syscall sys/sys/syscall_mi.h:176 [inline] #8 syscall+0xbc6 sys/arch/amd64/amd64/trap.c:577 #9 Xsyscall+0x128 exclusive rwlock sbufsnd r = 0 (0xffff80000149d030) #0 witness_lock+0x5bb stacktrace_save sys/sys/stacktrace.h:37 [inline] #0 witness_lock+0x5bb sys/kern/subr_witness.c:1160 #1 rw_do_enter_write+0x3ea sys/kern/kern_rwlock.c:316 #2 sblock+0xb7 sys/kern/uipc_socket2.c:536 #3 sosend+0x2e2 sys/kern/uipc_socket.c:630 #4 sendit+0x721 sys/kern/uipc_syscalls.c:779 #5 sys_sendto+0x8d sys/kern/uipc_syscalls.c:557 #6 syscall+0xbc6 mi_syscall sys/sys/syscall_mi.h:176 [inline] #6 syscall+0xbc6 sys/arch/amd64/amd64/trap.c:577 #7 Xsyscall+0x128 Process 93878 (syz-executor) thread 0xffff8000ffff07d8 (126892) exclusive rrwlock inode r = 0 (0xfffffd806f494e30) #0 witness_lock+0x5bb stacktrace_save sys/sys/stacktrace.h:37 [inline] #0 witness_lock+0x5bb sys/kern/subr_witness.c:1160 #1 rw_do_enter_write+0x3ea sys/kern/kern_rwlock.c:316 #2 rrw_enter+0xc6 sys/kern/kern_rwlock.c:616 #3 VOP_LOCK+0xa6 sys/kern/vfs_vops.c:524 #4 vn_lock+0xa4 sys/kern/vfs_vnops.c:570 #5 vget+0x2bd sys/kern/vfs_subr.c:694 #6 ktrwriteraw+0x172 sys/kern/kern_ktrace.c:688 #7 ktrsyscall+0x32b ktrwrite sys/kern/kern_ktrace.c:-1 [inline] #7 ktrsyscall+0x32b sys/kern/kern_ktrace.c:183 #8 syscall+0x2e6 mi_syscall sys/sys/syscall_mi.h:154 [inline] #8 syscall+0x2e6 sys/arch/amd64/amd64/trap.c:577 #9 Xsyscall+0x128 exclusive kernel_lock &kernel_lock r = 0 (0xffffffff8393e770) #0 witness_lock+0x5bb stacktrace_save sys/sys/stacktrace.h:37 [inline] #0 witness_lock+0x5bb sys/kern/subr_witness.c:1160 #1 ktrsyscall+0x2b3 ktrwrite sys/kern/kern_ktrace.c:-1 [inline] #1 ktrsyscall+0x2b3 sys/kern/kern_ktrace.c:183 #2 syscall+0x2e6 mi_syscall sys/sys/syscall_mi.h:154 [inline] #2 syscall+0x2e6 sys/arch/amd64/amd64/trap.c:577 #3 Xsyscall+0x128 ddb{1}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 10217 11251K 11951K 166960K 12768 0 pcb 22 14K 16K 166960K 397 0 rtable 282 14K 14K 166960K 628 0 pf 36 18K 22K 166960K 236 0 ifaddr 42 7K 8K 166960K 105 0 ifgroup 55 2K 2K 166960K 162 0 sysctl 4 1K 1K 166960K 6 0 counters 64 36K 37K 166960K 168 0 ioctlops 0 0K 4K 166960K 1675 0 iov 0 0K 16K 166960K 149 0 mount 1 1K 1K 166960K 1 0 log 0 0K 0K 166960K 4 0 vnodes 1494 94K 94K 166960K 2377 0 UFS quota 1 32K 32K 166960K 1 0 UFS mount 5 36K 36K 166960K 5 0 shm 2 1K 5K 166960K 13 0 VM map 2 1K 1K 166960K 2 0 sem 12 0K 0K 166960K 33 0 dirhash 12 2K 2K 166960K 39 0 ACPI 1692 195K 286K 166960K 12470 0 file desc 17 61K 93K 166960K 1069 0 sigio 0 0K 0K 166960K 85 0 proc 72 91K 140K 166960K 746 0 subproc 72 4K 4K 166960K 108 0 NFS srvsock 1 0K 0K 166960K 1 0 NFS daemon 1 16K 16K 166960K 1 0 ip_moptions 0 0K 0K 166960K 117 0 in_multi 94 6K 7K 166960K 183 0 ether_multi 1 0K 0K 166960K 9 0 mrt 1 0K 0K 166960K 8 0 ISOFS mount 1 32K 32K 166960K 1 0 MSDOSFS mount 1 16K 16K 166960K 1 0 ttys 91 413K 413K 166960K 91 0 exec 0 0K 1K 166960K 646 0 fusefs mount 1 32K 32K 166960K 1 0 pfkey data 0 0K 0K 166960K 3 0 tdb 3 0K 0K 166960K 3 0 VM swap 8 62K 64K 166960K 10 0 UVM amap 241 167K 181K 166960K 11472 0 UVM aobj 28 4K 6K 166960K 30 0 pinsyscall 42 84K 106K 166960K 2289 0 memdesc 1 4K 4K 166960K 1 0 crypto data 1 1K 1K 166960K 1 0 ip6_options 2 0K 0K 166960K 64 0 NDP 12 0K 1K 166960K 71 0 temp 74 8686K 8940K 166960K 29849 0 kqueue 14 22K 30K 166960K 193 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 24 0 0 1 0 1 1 0 8 0 rtpcb 120 124 0 119 1 0 1 1 0 8 0 rtentry 176 190 0 73 6 0 6 6 0 8 0 unpcb 144 863 0 843 9 8 1 4 0 8 0 syncache 336 5 0 4 2 1 1 1 0 8 0 tcpcb 808 473 0 465 11 9 2 8 0 8 0 arp 128 28 0 9 1 0 1 1 0 8 0 inpcb 384 1770 0 1747 20 17 3 15 0 8 0 nd6 144 47 0 17 2 0 2 2 0 8 0 pkpcb 40 44 0 44 2 2 0 1 0 8 0 kcovpl 48 12 0 4 1 0 1 1 0 8 0 ppxss 1192 36 0 36 1 1 0 1 0 8 0 pppxif 1504 10 0 10 2 2 0 1 0 8 0 pffrag 232 7 0 0 1 0 1 1 0 482 0 pffrnode 88 7 0 0 1 0 1 1 0 8 0 pffrent 40 11 0 4 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 12 0 5 1 0 1 1 0 8 0 pfanchor 1288 7 0 0 1 0 1 1 0 8 0 pftag 88 4 0 1 1 0 1 1 0 8 0 pfstitem 24 72 0 21 1 0 1 1 0 8 0 pfstkey 128 72 0 21 2 0 2 2 0 8 0 pfstate 384 72 0 21 6 0 6 6 0 8 0 pfrule 1344 36 0 24 3 2 1 2 0 8 0 rttmr 136 1 0 1 1 1 0 1 0 8 0 art_heap8 4096 3 0 0 3 0 3 3 0 8 0 art_heap4 256 836 0 365 31 1 30 30 0 8 0 art_table 32 839 0 365 4 0 4 4 0 8 0 art_node 16 186 0 79 1 0 1 1 0 8 0 sysvmsgpl 40 14 0 10 1 0 1 1 0 8 0 semapl 112 30 0 20 1 0 1 1 0 8 0 shmpl 112 27 0 2 1 0 1 1 0 8 0 dirhash 1024 35 0 18 3 0 3 3 0 8 0 dino2pl 256 3329 0 1814 96 0 96 96 0 8 0 ffsino 288 3329 0 1814 109 0 109 109 0 8 0 nchpl 144 4693 0 2989 64 0 64 64 0 8 0 rtmask 32 3 0 3 2 2 0 1 0 8 0 uvmvnodes 80 2801 0 0 58 0 58 58 0 8 0 vnodes 216 2801 0 0 156 0 156 156 0 8 0 namei 1024 16845 0 16845 1 0 1 1 0 8 1 percpumem 16 98 0 52 1 0 1 1 0 8 0 pfiaddrpl 120 2 0 0 1 0 1 1 0 8 0 kstatmem 264 92 0 68 3 1 2 3 0 8 0 acpiwqpl 32 1 0 1 1 0 1 1 1 8 1 scsiplug 72 7 0 7 2 1 1 1 0 8 1 scxspl 216 14453 0 14453 10 9 1 8 1 8 1 plimitpl 152 149 0 130 1 0 1 1 0 8 0 sigapl 424 1371 0 1319 8 2 6 7 0 8 0 futexpl 64 14079 0 14075 1 0 1 1 0 8 0 knotepl 120 547 0 0 17 0 17 17 0 8 0 kqueuepl 224 348 0 337 4 3 1 3 0 8 0 pipepl 336 191 0 164 3 0 3 3 0 8 0 fdescpl 520 1351 0 1320 3 0 3 3 0 8 0 filepl 160 8762 0 8531 18 7 11 17 0 8 0 lockfpl 104 276 0 274 1 0 1 1 0 8 0 lockfspl 48 115 0 113 1 0 1 1 0 8 0 sessionpl 144 28 0 19 1 0 1 1 0 8 0 pgrppl 48 52 0 35 1 0 1 1 0 8 0 ucredpl 104 926 0 912 1 0 1 1 0 8 0 zombiepl 144 1322 0 1319 1 0 1 1 0 8 0 processpl 1192 1371 0 1319 5 0 5 5 0 8 0 procpl 656 2878 0 2818 7 1 6 6 0 8 0 srpgc 96 8 0 8 2 2 0 1 0 8 0 sosppl 168 13 0 13 1 1 0 1 0 8 0 sockpl 728 2815 0 2768 25 20 5 16 0 8 0 mcl64k 65536 5 0 0 1 0 1 1 0 8 0 mcl16k 16384 1 0 0 1 0 1 1 0 8 0 mcl12k 12288 1 0 0 1 0 1 1 0 8 0 mcl9k 9216 3 0 0 1 0 1 1 0 8 0 mcl8k 8192 3 0 0 1 0 1 1 0 8 0 mcl4k 4096 115 0 0 15 0 15 15 0 8 0 mcl2k 2048 37 0 0 5 0 5 5 0 8 0 mtagpl 96 123 0 0 3 0 3 3 0 8 0 mbufpl 256 340 0 0 21 0 21 21 0 8 0 bufpl 280 4124 0 133 286 0 286 286 0 8 0 anonpl 24 189865 0 186413 50 21 29 46 0 184 0 amapchunkpl 152 36787 0 36293 31 7 24 28 0 158 1 amappl16 200 3157 0 3124 18 15 3 15 0 8 0 amappl15 192 4 0 4 1 1 0 1 0 8 0 amappl14 184 126 0 114 1 0 1 1 0 8 0 amappl13 176 4 0 4 2 2 0 1 0 8 0 amappl12 168 2084 0 2053 4 1 3 3 0 8 0 amappl11 160 52 0 38 1 0 1 1 0 8 0 amappl10 152 47 0 47 1 1 0 1 0 8 0 amappl9 144 268 0 267 2 1 1 1 0 8 0 amappl8 136 42 0 40 1 0 1 1 0 8 0 amappl7 128 119 0 106 1 0 1 1 0 8 0 amappl6 120 253 0 249 1 0 1 1 0 8 0 amappl5 112 141 0 131 1 0 1 1 0 8 0 amappl4 104 341 0 322 1 0 1 1 0 8 0 amappl3 96 7404 0 7289 5 1 4 4 0 8 0 amappl2 88 715 0 651 2 0 2 2 0 8 0 amappl1 80 12545 0 11938 15 1 14 15 0 8 0 amappl 88 10529 0 10363 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 7 0 7 2 2 0 1 0 8 0 dma128 128 255 0 255 2 2 0 1 0 8 0 dma64 64 7 0 7 2 2 0 1 0 8 0 dma32 32 8 0 8 2 2 0 1 0 8 0 dma16 16 18 0 17 1 0 1 1 0 8 0 aobjpl 72 29 0 2 1 0 1 1 0 8 0 uaddrrnd 24 1351 0 1320 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 1351 0 1320 1 0 1 1 0 8 0 vmmpekpl 168 12056 0 12013 3 0 3 3 0 8 0 vmmpepl 168 88446 0 86444 105 13 92 100 0 357 0 vmsppl 480 1350 0 1320 6 1 5 5 0 8 0 rwobjpl 72 26704 0 22934 73 2 71 73 0 8 0 pdppl 4096 2710 0 2640 112 40 72 86 0 8 2 pvpl 32 15687 0 0 128 1 127 127 0 265 0 pmappl 256 1350 0 1320 3 0 3 3 0 8 0 extentpl 40 45 0 27 1 0 1 1 0 8 0 phpool 112 422 0 54 11 0 11 11 0 8 0 ddb{1}> machine ddbcpu 0 Stopped at x86_ipi_db+0x27: addq $0x8,%rsp x86_ipi_db(ffffffff837b8ff0) 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(ffffffff8393e568) at __mp_lock+0x192 __mp_lock_spin sys/kern/kern_lock.c:113 [inline] __mp_lock(ffffffff8393e568) at __mp_lock+0x192 sys/kern/kern_lock.c:144 softintr_dispatch(0) at softintr_dispatch+0x5b sys/arch/amd64/amd64/softintr.c:88 Xsoftclock() at Xsoftclock+0x27 cnputc(31) at cnputc+0x61 sys/dev/cons.c:218 db_putchar(31) at db_putchar+0x65c sys/ddb/db_output.c:155 kprintf() at kprintf+0x2aba sys/kern/subr_prf.c:1065 db_printf(ffffffff833f8186) at db_printf+0x9b sys/kern/subr_prf.c:-1 fault(ffffffff83397e46) at fault+0xa7 sys/arch/amd64/amd64/trap.c:157 kpageflttrap(ffff80003b819f30,ffff8000014d504a) at kpageflttrap+0x385 sys/arch/amd64/amd64/trap.c:290 kerntrap(ffff80003b819f30) at kerntrap+0x14a sys/arch/amd64/amd64/trap.c:332 alltraps_kern_meltdown() at alltraps_kern_meltdown+0x7b end trace frame: 0xffff80003b81a060, count: 0 ddb{0}> trace x86_ipi_db(ffffffff837b8ff0) 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(ffffffff8393e568) at __mp_lock+0x192 __mp_lock_spin sys/kern/kern_lock.c:113 [inline] __mp_lock(ffffffff8393e568) at __mp_lock+0x192 sys/kern/kern_lock.c:144 softintr_dispatch(0) at softintr_dispatch+0x5b sys/arch/amd64/amd64/softintr.c:88 Xsoftclock() at Xsoftclock+0x27 cnputc(31) at cnputc+0x61 sys/dev/cons.c:218 db_putchar(31) at db_putchar+0x65c sys/ddb/db_output.c:155 kprintf() at kprintf+0x2aba sys/kern/subr_prf.c:1065 db_printf(ffffffff833f8186) at db_printf+0x9b sys/kern/subr_prf.c:-1 fault(ffffffff83397e46) at fault+0xa7 sys/arch/amd64/amd64/trap.c:157 kpageflttrap(ffff80003b819f30,ffff8000014d504a) at kpageflttrap+0x385 sys/arch/amd64/amd64/trap.c:290 kerntrap(ffff80003b819f30) at kerntrap+0x14a sys/arch/amd64/amd64/trap.c:332 alltraps_kern_meltdown() at alltraps_kern_meltdown+0x7b arp_rtrequest(ffff800000039058,1,fffffd8067343900) at arp_rtrequest+0x66f arprequest sys/netinet/if_ether.c:281 [inline] arp_rtrequest(ffff800000039058,1,fffffd8067343900) at arp_rtrequest+0x66f sys/netinet/if_ether.c:184 rtrequest(1,ffff80003b81a210,0,ffff80003b81a190,0) at rtrequest+0xc5c sys/net/route.c:1117 rtm_output(ffff8000014f0500,ffff80003b81a2b8,ffff80003b81a210,0,0) at rtm_output+0x876 sys/net/rtsock.c:973 route_output(fffffd8067254d00,ffff80000149ce58) at route_output+0x9a1 sys/net/rtsock.c:878 route_send(ffff80000149ce58,fffffd8067254d00,0,0) at route_send+0xd7 sys/net/rtsock.c:342 sosend(ffff80000149ce58,0,ffff80003b81a458,0,0,808) at sosend+0x804 sys/kern/uipc_socket.c:-1 sendit(ffff80003c455c60,3,ffff80003b81a550,808,ffff80003b81a600) at sendit+0x721 sys/kern/uipc_syscalls.c:779 sys_sendto(ffff80003c455c60,ffff80003b81a6b0,ffff80003b81a600) at sys_sendto+0x8d sys/kern/uipc_syscalls.c:557 syscall(ffff80003b81a6b0) at syscall+0xbc6 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80003b81a6b0) at syscall+0xbc6 sys/arch/amd64/amd64/trap.c:577 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x25f7592fc40, count: -24 ddb{0}> machine ddbcpu 1 Stopped at savectx+0xae: movl $0,%gs:0x680 savectx() at savectx+0xae end of kernel end trace frame: 0x74738f87a800, count: 14 ddb{1}> trace savectx() at savectx+0xae end of kernel end trace frame: 0x74738f87a800, count: -1