witness: lock order reversal: 1st 0xffffffff82cc8bd0 &sched_lock (&sched_lock) 2nd 0xffff800029bd0db8 &pr->ps_mtx (&pr->ps_mtx) lock order "&pr->ps_mtx"(mutex) -> "&sched_lock"(sched_lock) first seen at: #0 __mp_lock+0xa2 read_rflags machine/cpufunc.h:195 [inline] #0 __mp_lock+0xa2 intr_disable machine/cpufunc.h:216 [inline] #0 __mp_lock+0xa2 sys/kern/kern_lock.c:142 #1 donice+0x178 sys/kern/kern_resource.c:218 #2 syscall+0x5e2 mi_syscall sys/sys/syscall_mi.h:110 [inline] #2 syscall+0x5e2 sys/arch/amd64/amd64/trap.c:623 #3 Xsyscall+0x128 lock order "&sched_lock"(sched_lock) -> "&pr->ps_mtx"(mutex) first seen at: #0 mtx_enter+0x3e sys/kern/kern_lock.c:265 #1 single_thread_set+0x35a single_thread_wait sys/kern/kern_sig.c:2172 [inline] #1 single_thread_set+0x35a sys/kern/kern_sig.c:2155 #2 sigexit+0x90 sys/kern/kern_sig.c:1562 #3 postsig+0x4a9 sys/kern/kern_sig.c:1494 #4 userret+0x16e sys/kern/kern_sig.c:1987 #5 syscall+0x4e7 mi_syscall_return sys/sys/syscall_mi.h:137 [inline] #5 syscall+0x4e7 sys/arch/amd64/amd64/trap.c:644 #6 Xsyscall+0x128 Stopped at db_enter+0x1c: addq $0x8,%rsp ddb{0}> ddb{0}> set $lines = 0 ddb{0}> set $maxwidth = 0 ddb{0}> show panic the kernel did not panic ddb{0}> trace db_enter() at db_enter+0x1c sys/arch/amd64/amd64/db_interface.c:437 witness_checkorder(ffff800029bd0db8,9,0) at witness_checkorder+0x10b7 witness_debugger sys/kern/subr_witness.c:2510 [inline] witness_checkorder(ffff800029bd0db8,9,0) at witness_checkorder+0x10b7 sys/kern/subr_witness.c:1110 mtx_enter(ffff800029bd0da8) at mtx_enter+0x3e sys/kern/kern_lock.c:265 single_thread_set(ffff80002128b7f0,0,1) at single_thread_set+0x35a single_thread_wait sys/kern/kern_sig.c:2172 [inline] single_thread_set(ffff80002128b7f0,0,1) at single_thread_set+0x35a sys/kern/kern_sig.c:2155 sigexit(ffff80002128b7f0,6) at sigexit+0x90 sys/kern/kern_sig.c:1562 postsig(ffff80002128b7f0,6,ffff80002a9eb3d8) at postsig+0x4a9 sys/kern/kern_sig.c:1494 userret(ffff80002128b7f0) at userret+0x16e sys/kern/kern_sig.c:1987 syscall(ffff80002a9eb510) at syscall+0x4e7 mi_syscall_return sys/sys/syscall_mi.h:137 [inline] syscall(ffff80002a9eb510) at syscall+0x4e7 sys/arch/amd64/amd64/trap.c:644 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xbd841c9ab70, count: -9 ddb{0}> show registers rdi 0x3 rsi 0x40000 acpi_pdirpa+0x2be63 rbp 0xffff80002a9eb0e0 rbx 0x3 rdx 0xffff800000cf9ac0 rcx 0xffff80002128b7f0 rax 0x3ffff acpi_pdirpa+0x2be62 r8 0xffff80002a9eb050 r9 0x8080808080808080 r10 0xa6c6e0c99a03238a r11 0xd199ee86a6388a15 r12 0xfffffd8003a0a900 r13 0 r14 0xfffffd80039fa260 r15 0xfffffd80031c7bc0 rip 0xffffffff81b6e27c db_enter+0x1c cs 0x8 rflags 0x246 rsp 0xffff80002a9eb0d0 ss 0x10 db_enter+0x1c: addq $0x8,%rsp ddb{0}> show proc PROC (syz-executor.1) pid=133071 stat=onproc flags process=500010 proc=4002000 pri=32, usrpri=82, nice=20 forw=0xffffffffffffffff, list=0xffff80002128b2a0,0xffffffff82c90e98 process=0xffff800029bd0ca8 user=0xffff80002a9e6000, vmspace=0xfffffd806a002930 estcpu=36, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 55431 312426 90903 32767 4 0x582010 syz-executor.1 *55431 133071 90903 32767 7 0x4502010 syz-executor.1 64655 148372 79963 32767 2 0x10 syz-executor.7 67512 137159 67445 32767 2 0x10 syz-executor.2 79963 428445 50349 32767 3 0x90 nanoslp syz-executor.7 57648 383336 84540 32767 7 0x10 syz-executor.4 69516 104518 70755 32767 3 0x90 nanoslp syz-executor.3 19269 10361 57258 32767 3 0x90 nanoslp syz-executor.5 50349 160109 21510 0 3 0x82 wait syz-executor.7 15464 285636 75286 32767 3 0x10 biowait syz-executor.6 84540 80755 21510 0 3 0x82 wait syz-executor.4 75286 84120 21510 0 3 0x82 wait syz-executor.6 57258 320898 21510 0 3 0x82 wait syz-executor.5 70755 377365 21510 0 3 0x82 wait syz-executor.3 67445 437037 95240 32767 3 0x90 nanoslp syz-executor.2 95240 131616 21510 0 3 0x82 wait syz-executor.2 712 448502 54200 32767 3 0x10 biowait syz-executor.0 90903 272118 18431 32767 3 0x90 nanoslp syz-executor.1 18431 517255 21510 0 3 0x82 wait syz-executor.1 54200 329032 21510 0 3 0x82 wait syz-executor.0 21510 310270 3768 0 3 0x2000082 wait syz-fuzzer 21510 45592 3768 0 3 0x6000082 nanoslp syz-fuzzer 21510 384592 3768 0 3 0x6000082 wait syz-fuzzer 21510 78477 3768 0 3 0x6000082 wait syz-fuzzer 21510 346025 3768 0 3 0x6000082 thrsleep syz-fuzzer 21510 355246 3768 0 3 0x6000082 wait syz-fuzzer 21510 67807 3768 0 3 0x6000082 wait syz-fuzzer 21510 335335 3768 0 3 0x6000082 wait syz-fuzzer 21510 384328 3768 0 3 0x6000082 thrsleep syz-fuzzer 21510 73401 3768 0 3 0x6000082 wait syz-fuzzer 21510 482423 3768 0 3 0x6000082 thrsleep syz-fuzzer 21510 268007 3768 0 3 0x6000082 thrsleep syz-fuzzer 21510 433147 3768 0 3 0x6000082 wait syz-fuzzer 21510 134966 3768 0 3 0x6000082 thrsleep syz-fuzzer 21510 225241 3768 0 3 0x6000082 kqread syz-fuzzer 21510 516119 3768 0 3 0x6000082 thrsleep syz-fuzzer 3768 132775 20374 0 3 0x10008a sigsusp ksh 20374 518825 20902 0 3 0x9a kqread sshd 46618 300784 1 0 3 0x100083 ttyin getty 20902 95382 1 0 3 0x88 kqread sshd 37780 37309 22056 73 3 0x1100090 kqread syslogd 22056 404617 1 0 3 0x100082 netio syslogd 87395 147751 1 0 3 0x100080 kqread resolvd 85023 117935 28300 77 3 0x100092 kqread dhcpleased 32551 511188 28300 77 3 0x100092 kqread dhcpleased 28300 153901 1 0 3 0x80 kqread dhcpleased 21742 296262 0 0 3 0x14200 bored smr 89684 60635 0 0 2 0x14200 zerothread 33487 498892 0 0 3 0x14200 aiodoned aiodoned 64957 283895 0 0 3 0x14200 syncer update 57915 384928 0 0 3 0x14200 cleaner cleaner 60123 313730 0 0 3 0x14200 reaper reaper 83033 201978 0 0 3 0x14200 pgdaemon pagedaemon 86567 97912 0 0 3 0x14200 bored viomb 99779 513163 0 0 3 0x40014200 acpi0 acpi0 34793 292686 0 0 3 0x40014200 idle1 20266 357770 0 0 3 0x14200 bored softnet3 98277 138824 0 0 3 0x14200 bored softnet2 5499 31120 0 0 3 0x14200 bored softnet1 90441 10527 0 0 3 0x14200 bored softnet0 56011 378480 0 0 3 0x14200 bored systqmp 38588 347632 0 0 3 0x14200 bored systq 64396 405892 0 0 3 0x40014200 bored softclock 31215 183394 0 0 3 0x40014200 idle0 1 134366 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{0}> show all locks CPU 0: exclusive sched_lock &sched_lock r = 0 (0xffffffff82cc8bd0) #0 witness_lock+0x447 #1 single_thread_set+0x179 sys/kern/kern_sig.c:2113 #2 sigexit+0x90 sys/kern/kern_sig.c:1562 #3 postsig+0x4a9 sys/kern/kern_sig.c:1494 #4 userret+0x16e sys/kern/kern_sig.c:1987 #5 syscall+0x4e7 mi_syscall_return sys/sys/syscall_mi.h:137 [inline] #5 syscall+0x4e7 sys/arch/amd64/amd64/trap.c:644 #6 Xsyscall+0x128 Process 55431 (syz-executor.1) thread 0xffff80002128b7f0 (133071) exclusive kernel_lock &kernel_lock r = 0 (0xffffffff82ca0228) #0 witness_lock+0x447 #1 postsig+0x49e sys/kern/kern_sig.c:1500 #2 userret+0x16e sys/kern/kern_sig.c:1987 #3 syscall+0x4e7 mi_syscall_return sys/sys/syscall_mi.h:137 [inline] #3 syscall+0x4e7 sys/arch/amd64/amd64/trap.c:644 #4 Xsyscall+0x128 exclusive sched_lock &sched_lock r = 0 (0xffffffff82cc8bd0) #0 witness_lock+0x447 #1 single_thread_set+0x179 sys/kern/kern_sig.c:2113 #2 sigexit+0x90 sys/kern/kern_sig.c:1562 #3 postsig+0x4a9 sys/kern/kern_sig.c:1494 #4 userret+0x16e sys/kern/kern_sig.c:1987 #5 syscall+0x4e7 mi_syscall_return sys/sys/syscall_mi.h:137 [inline] #5 syscall+0x4e7 sys/arch/amd64/amd64/trap.c:644 #6 Xsyscall+0x128 Process 15464 (syz-executor.6) thread 0xffff80002121a570 (285636) exclusive rrwlock inode r = 0 (0xfffffd80667216f8) #0 witness_lock+0x447 #1 rw_enter+0x3c8 sys/kern/kern_rwlock.c:309 #2 rrw_enter+0x8c sys/kern/kern_rwlock.c:464 #3 VOP_LOCK+0x8b sys/kern/vfs_vops.c:518 #4 ufs_ihashins+0x46 sys/ufs/ufs/ufs_ihash.c:140 #5 ffs_vget+0x141 sys/ufs/ffs/ffs_vfsops.c:1343 #6 ffs_inode_alloc+0x1c2 sys/ufs/ffs/ffs_alloc.c:394 #7 ufs_mkdir+0xf8 sys/ufs/ufs/ufs_vnops.c:1149 #8 VOP_MKDIR+0xc3 sys/kern/vfs_vops.c:388 #9 domkdirat+0x125 sys/kern/vfs_syscalls.c:3073 #10 syscall+0x5e2 mi_syscall sys/sys/syscall_mi.h:110 [inline] #10 syscall+0x5e2 sys/arch/amd64/amd64/trap.c:623 #11 Xsyscall+0x128 exclusive rrwlock inode r = 0 (0xfffffd8067de1c50) #0 witness_lock+0x447 #1 rw_enter+0x3c8 sys/kern/kern_rwlock.c:309 #2 rrw_enter+0x8c sys/kern/kern_rwlock.c:464 #3 VOP_LOCK+0x8b sys/kern/vfs_vops.c:518 #4 vn_lock+0x84 sys/kern/vfs_vnops.c:564 #5 vfs_lookup+0xd5 sys/kern/vfs_lookup.c:418 #6 namei+0x55a sys/kern/vfs_lookup.c:250 #7 domkdirat+0x79 sys/kern/vfs_syscalls.c:3058 #8 syscall+0x5e2 mi_syscall sys/sys/syscall_mi.h:110 [inline] #8 syscall+0x5e2 sys/arch/amd64/amd64/trap.c:623 #9 Xsyscall+0x128 Process 712 (syz-executor.0) thread 0xffff8000211f4810 (448502) exclusive rrwlock inode r = 0 (0xfffffd80667214d8) #0 witness_lock+0x447 #1 rw_enter+0x3c8 sys/kern/kern_rwlock.c:309 #2 rrw_enter+0x8c sys/kern/kern_rwlock.c:464 #3 VOP_LOCK+0x8b sys/kern/vfs_vops.c:518 #4 vn_lock+0x84 sys/kern/vfs_vnops.c:564 #5 vget+0x200 sys/kern/vfs_subr.c:676 #6 ufs_ihashget+0x121 sys/ufs/ufs/ufs_ihash.c:119 #7 ffs_vget+0x7c sys/ufs/ffs/ffs_vfsops.c:1314 #8 ufs_lookup+0x13ba sys/ufs/ufs/ufs_lookup.c:487 #9 VOP_LOOKUP+0x5c sys/kern/vfs_vops.c:85 #10 vfs_lookup+0x6e2 sys/kern/vfs_lookup.c:566 #11 namei+0x55a sys/kern/vfs_lookup.c:250 #12 dounlinkat+0x9d sys/kern/vfs_syscalls.c:1847 #13 syscall+0x5e2 mi_syscall sys/sys/syscall_mi.h:110 [inline] #13 syscall+0x5e2 sys/arch/amd64/amd64/trap.c:623 #14 Xsyscall+0x128 exclusive rrwlock inode r = 0 (0xfffffd8069bf36f8) #0 witness_lock+0x447 #1 rw_enter+0x3c8 sys/kern/kern_rwlock.c:309 #2 rrw_enter+0x8c sys/kern/kern_rwlock.c:464 #3 VOP_LOCK+0x8b sys/kern/vfs_vops.c:518 #4 vn_lock+0x84 sys/kern/vfs_vnops.c:564 #5 vfs_lookup+0xd5 sys/kern/vfs_lookup.c:418 #6 namei+0x55a sys/kern/vfs_lookup.c:250 #7 dounlinkat+0x9d sys/kern/vfs_syscalls.c:1847 #8 syscall+0x5e2 mi_syscall sys/sys/syscall_mi.h:110 [inline] #8 syscall+0x5e2 sys/arch/amd64/amd64/trap.c:623 #9 Xsyscall+0x128 ddb{0}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 10184 6408K 6420K 78643K 11262 0 pcb 13 8K 8K 78643K 13 0 rtable 234 6K 6K 78643K 352 0 pf 29 8K 8K 78643K 29 0 ifaddr 44 15K 15K 78643K 46 0 ifgroup 50 2K 2K 78643K 50 0 counters 60 35K 35K 78643K 60 0 ioctlops 0 0K 2K 78643K 29 0 iov 0 0K 0K 78643K 297 0 mount 1 1K 1K 78643K 1 0 log 0 0K 0K 78643K 4 0 vnodes 1279 80K 80K 78643K 1328 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 17K 78643K 398 0 VM map 2 1K 1K 78643K 2 0 sem 11 0K 0K 78643K 11 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1697 195K 286K 78643K 12548 0 file desc 21 77K 125K 78643K 7496 0 sigio 0 0K 0K 78643K 2 0 proc 56 78K 103K 78643K 471 0 subproc 104 6K 6K 78643K 104 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 in_multi 99 7K 7K 78643K 99 0 ether_multi 1 0K 0K 78643K 1 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 49 228K 228K 78643K 49 0 exec 0 0K 1K 78643K 364 0 tdb 3 0K 0K 78643K 3 0 pagedep 1 8K 8K 78643K 1 0 inodedep 1 32K 32K 78643K 1 0 newblk 1 0K 0K 78643K 1 0 VM swap 8 62K 64K 78643K 10 0 UVM amap 282 81K 82K 78643K 64472 0 UVM aobj 131 17K 17K 78643K 131 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 NDP 11 0K 2K 78643K 27 0 temp 38 5907K 5971K 78643K 18824 0 kqueue 12 18K 20K 78643K 35 0 SYN cache 2 16K 16K 78643K 2 0 ddb{0}> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle plcache 128 22 0 0 1 0 1 1 0 8 0 rtpcb 120 37 0 34 1 0 1 1 0 8 0 rtentry 112 111 0 1 4 0 4 4 0 8 0 unpcb 144 8079 0 8066 6 0 6 6 0 8 5 syncache 304 4 0 4 1 1 0 1 0 8 0 tcpqe 32 194 0 194 1 1 0 1 0 8 0 tcpcb 808 8 0 4 1 0 1 1 0 8 0 arp 120 18 0 0 1 0 1 1 0 8 0 inpcb 368 58 0 51 1 0 1 1 0 8 0 nd6 136 24 0 0 1 0 1 1 0 8 0 kcovpl 48 8 0 0 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 452 0 0 29 0 29 29 0 8 0 art_table 32 453 0 0 4 0 4 4 0 8 0 art_node 16 110 0 10 1 0 1 1 0 8 0 semapl 112 9 0 0 1 0 1 1 0 8 0 shmpl 112 128 0 0 4 0 4 4 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 8927 0 7488 91 0 91 91 0 8 0 ffsino 272 8927 0 7488 97 0 97 97 0 8 0 nchpl 144 20244 0 18565 63 0 63 63 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 52944 0 52943 2 1 1 2 0 8 0 percpumem 16 43 0 0 1 0 1 1 0 8 0 kstatmem 264 22 0 0 2 0 2 2 0 8 0 scxspl 216 50980 0 50978 11 9 2 8 1 8 1 plimitpl 152 41 0 18 1 0 1 1 0 8 0 sigapl 424 7792 0 7741 7 0 7 7 0 8 0 futexpl 64 52521 0 52521 1 0 1 1 0 8 1 knotepl 120 118 0 0 4 0 4 4 0 8 0 kqueuepl 216 34 0 26 1 0 1 1 0 8 0 pipepl 320 135 0 107 3 0 3 3 0 8 0 fdescpl 496 7775 0 7743 7 2 5 6 0 8 0 filepl 152 30407 0 30173 15 0 15 15 0 8 6 lockfpl 104 6 0 4 1 0 1 1 0 8 0 lockfspl 48 4 0 2 1 0 1 1 0 8 0 sessionpl 144 23 0 7 1 0 1 1 0 8 0 pgrppl 48 58 0 42 1 0 1 1 0 8 0 ucredpl 104 2874 0 2856 1 0 1 1 0 8 0 zombiepl 144 7743 0 7741 1 0 1 1 0 8 0 processpl 1072 7792 0 7741 5 1 4 5 0 8 0 procpl 680 15541 0 15474 7 0 7 7 0 8 0 sockpl 488 8350 0 8327 23 12 11 20 0 8 8 mcl64k 65536 17 0 0 3 0 3 3 0 8 0 mcl16k 16384 18 0 0 3 0 3 3 0 8 0 mcl12k 12288 18 0 0 2 0 2 2 0 8 0 mcl9k 9216 17 0 0 2 0 2 2 0 8 0 mcl8k 8192 18 0 0 3 0 3 3 0 8 0 mcl4k 4096 23 0 0 3 1 2 3 0 8 0 mcl2k2 2112 6 0 0 1 0 1 1 0 8 0 mcl2k 2048 264 0 0 33 0 33 33 0 8 0 mtagpl 96 3 0 0 1 0 1 1 0 8 0 mbufpl 256 316 0 0 18 0 18 18 0 8 0 bufpl 288 11496 0 5167 453 0 453 453 0 8 0 anonpl 24 680129 0 673149 63 17 46 57 0 186 0 amapchunkpl 152 203191 0 202499 37 4 33 34 0 158 3 amappl16 200 12119 0 11979 9 1 8 8 0 8 0 amappl15 192 13 0 13 2 2 0 1 0 8 0 amappl14 184 159 0 145 2 1 1 2 0 8 0 amappl13 176 7 0 6 2 1 1 1 0 8 0 amappl12 168 8403 0 8369 2 0 2 2 0 8 0 amappl11 160 48 0 37 1 0 1 1 0 8 0 amappl10 152 36 0 24 1 0 1 1 0 8 0 amappl9 144 249 0 247 1 0 1 1 0 8 0 amappl8 136 232 0 173 3 0 3 3 0 8 0 amappl7 128 103 0 92 2 0 2 2 0 8 0 amappl6 120 240 0 224 2 1 1 2 0 8 0 amappl5 112 302 0 293 1 0 1 1 0 8 0 amappl4 104 1059 0 1024 3 1 2 3 0 8 0 amappl3 96 41762 0 41688 3 0 3 3 0 8 0 amappl2 88 8783 0 8711 3 1 2 3 0 8 0 amappl1 80 34127 0 33609 22 9 13 22 0 8 0 amappl 88 63962 0 63772 6 0 6 6 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 6 0 6 1 1 0 1 0 8 0 dma128 128 253 0 253 1 1 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 72 130 0 0 3 0 3 3 0 8 0 uaddrrnd 24 7775 0 7743 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 7775 0 7743 1 0 1 1 0 8 0 vmmpekpl 168 35526 0 35469 3 0 3 3 0 8 0 vmmpepl 168 427718 0 425719 114 15 99 112 0 357 2 vmsppl 464 7774 0 7743 7 2 5 6 0 8 0 rwobjpl 56 99049 0 91900 104 2 102 102 0 8 0 pdppl 4096 15558 0 15486 144 62 82 96 0 8 10 pvpl 32 2069407 0 2056743 355 73 282 352 0 265 171 pmappl 248 7774 0 7743 4 1 3 3 0 8 0 extentpl 40 56 0 38 1 0 1 1 0 8 0 phpool 112 895 0 66 24 0 24 24 0 8 0 ddb{0}> machine ddbcpu 0 Invalid cpu 0 ddb{0}> trace db_enter() at db_enter+0x1c sys/arch/amd64/amd64/db_interface.c:437 witness_checkorder(ffff800029bd0db8,9,0) at witness_checkorder+0x10b7 witness_debugger sys/kern/subr_witness.c:2510 [inline] witness_checkorder(ffff800029bd0db8,9,0) at witness_checkorder+0x10b7 sys/kern/subr_witness.c:1110 mtx_enter(ffff800029bd0da8) at mtx_enter+0x3e sys/kern/kern_lock.c:265 single_thread_set(ffff80002128b7f0,0,1) at single_thread_set+0x35a single_thread_wait sys/kern/kern_sig.c:2172 [inline] single_thread_set(ffff80002128b7f0,0,1) at single_thread_set+0x35a sys/kern/kern_sig.c:2155 sigexit(ffff80002128b7f0,6) at sigexit+0x90 sys/kern/kern_sig.c:1562 postsig(ffff80002128b7f0,6,ffff80002a9eb3d8) at postsig+0x4a9 sys/kern/kern_sig.c:1494 userret(ffff80002128b7f0) at userret+0x16e sys/kern/kern_sig.c:1987 syscall(ffff80002a9eb510) at syscall+0x4e7 mi_syscall_return sys/sys/syscall_mi.h:137 [inline] syscall(ffff80002a9eb510) at syscall+0x4e7 sys/arch/amd64/amd64/trap.c:644 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xbd841c9ab70, count: -9 ddb{0}> machine ddbcpu 1 Stopped at x86_ipi_db+0x1e: addq $0x8,%rsp ddb{1}> trace x86_ipi_db(ffff800020d58ff0) at x86_ipi_db+0x1e sys/arch/amd64/amd64/db_interface.c:393 x86_ipi_handler() at x86_ipi_handler+0xb7 sys/arch/amd64/amd64/ipi.c:106 Xresume_lapic_ipi() at Xresume_lapic_ipi+0x27 __mp_lock(ffffffff82ca0020) at __mp_lock+0x12e __mp_lock_spin sys/kern/kern_lock.c:116 [inline] __mp_lock(ffffffff82ca0020) at __mp_lock+0x12e sys/kern/kern_lock.c:147 syscall(ffff80002d203990) at syscall+0x5cd mi_syscall sys/sys/syscall_mi.h:110 [inline] syscall(ffff80002d203990) at syscall+0x5cd sys/arch/amd64/amd64/trap.c:623 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x74b74c7e1d90, count: -6