witness: lock order reversal: 1st 0xffffffff82c75c58 &sched_lock (&sched_lock) 2nd 0xffff80002121de70 &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{1}> ddb{1}> set $lines = 0 ddb{1}> set $maxwidth = 0 ddb{1}> show panic the kernel did not panic ddb{1}> trace db_enter() at db_enter+0x1c sys/arch/amd64/amd64/db_interface.c:437 witness_checkorder(ffff80002121de70,9,0) at witness_checkorder+0x10b7 witness_debugger sys/kern/subr_witness.c:2510 [inline] witness_checkorder(ffff80002121de70,9,0) at witness_checkorder+0x10b7 sys/kern/subr_witness.c:1110 mtx_enter(ffff80002121de60) at mtx_enter+0x3e sys/kern/kern_lock.c:265 single_thread_set(ffff8000211f5560,0,1) at single_thread_set+0x35a single_thread_wait sys/kern/kern_sig.c:2172 [inline] single_thread_set(ffff8000211f5560,0,1) at single_thread_set+0x35a sys/kern/kern_sig.c:2155 sigexit(ffff8000211f5560,6) at sigexit+0x90 sys/kern/kern_sig.c:1562 postsig(ffff8000211f5560,6,ffff8000212bbdf8) at postsig+0x4a9 sys/kern/kern_sig.c:1494 userret(ffff8000211f5560) at userret+0x16e sys/kern/kern_sig.c:1987 syscall(ffff8000212bbf30) at syscall+0x4e7 mi_syscall_return sys/sys/syscall_mi.h:137 [inline] syscall(ffff8000212bbf30) at syscall+0x4e7 sys/arch/amd64/amd64/trap.c:644 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xc2950459e80, count: -9 ddb{1}> show registers rdi 0x3 rsi 0xffffffff82c40e70 __sancov_gen_cov_switch_values.134 rbp 0xffff8000212bbb00 rbx 0x3 rdx 0x3fd rcx 0 rax 0x1 r8 0xffff8000212bba70 r9 0x8080808080808080 r10 0xcfdee2023b685e77 r11 0x2f2983fc8e02d1f3 r12 0xfffffd8003a0d900 r13 0 r14 0xfffffd8003a06630 r15 0xfffffd80031cabc0 rip 0xffffffff82131f9c db_enter+0x1c cs 0x8 rflags 0x246 rsp 0xffff8000212bbaf0 ss 0x10 db_enter+0x1c: addq $0x8,%rsp ddb{1}> show proc PROC (syz-executor.0) pid=12407 stat=onproc flags process=100000 proc=4002000 pri=32, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff8000211f4d68,0xffffffff82d74600 process=0xffff80002121dd60 user=0xffff8000212b6000, vmspace=0xfffffd807eff81d0 estcpu=36, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 73374 203013 90031 0 4 0x182000 syz-executor.0 *73374 12407 90031 0 7 0x4102000 syz-executor.0 90031 366134 60990 0 3 0x82 nanoslp syz-executor.0 60990 87918 59082 0 3 0x2000082 thrsleep syz-execprog 60990 355327 59082 0 3 0x6000082 thrsleep syz-execprog 60990 232657 59082 0 3 0x6000082 wait syz-execprog 60990 396764 59082 0 3 0x6000082 thrsleep syz-execprog 60990 362658 59082 0 3 0x6000082 thrsleep syz-execprog 60990 320308 59082 0 3 0x6000082 kqread syz-execprog 60990 301253 59082 0 3 0x6000082 thrsleep syz-execprog 60990 244156 59082 0 3 0x6000082 thrsleep syz-execprog 60990 467141 59082 0 3 0x6000082 thrsleep syz-execprog 60990 48961 59082 0 3 0x6000082 thrsleep syz-execprog 59082 274101 10762 0 3 0x10008a sigsusp ksh 10762 133767 15665 0 3 0x9a kqread sshd 44682 9640 1 0 3 0x100083 ttyin getty 15665 364915 1 0 3 0x88 kqread sshd 13420 164746 67346 74 3 0x1100092 bpf pflogd 67346 360740 1 0 3 0x80 netio pflogd 81770 442115 18860 73 3 0x1100090 kqread syslogd 18860 151573 1 0 3 0x100082 netio syslogd 78057 473417 1 0 3 0x100080 kqread resolvd 82805 294437 45536 77 3 0x100092 kqread dhcpleased 27417 504498 45536 77 3 0x100092 kqread dhcpleased 45536 322691 1 0 3 0x80 kqread dhcpleased 31074 185147 0 0 3 0x14200 bored smr 25832 234334 0 0 7 0x14200 zerothread 81791 135969 0 0 3 0x14200 aiodoned aiodoned 52210 202139 0 0 3 0x14200 syncer update 34092 308409 0 0 3 0x14200 cleaner cleaner 7281 61859 0 0 3 0x14200 reaper reaper 95952 500161 0 0 3 0x14200 pgdaemon pagedaemon 24426 15828 0 0 3 0x14200 bored viomb 34346 158091 0 0 3 0x40014200 acpi0 acpi0 81966 437308 0 0 3 0x40014200 idle1 91814 182278 0 0 3 0x14200 bored softnet3 63458 270778 0 0 3 0x14200 bored softnet2 63216 519173 0 0 3 0x14200 bored softnet1 78036 415475 0 0 3 0x14200 bored softnet0 95235 94012 0 0 3 0x14200 bored systqmp 93524 31181 0 0 3 0x14200 bored systq 92405 448108 0 0 3 0x40014200 bored softclock 99079 68649 0 0 3 0x40014200 idle0 1 469752 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{1}> show all locks CPU 1: exclusive sched_lock &sched_lock r = 0 (0xffffffff82c75c58) #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 73374 (syz-executor.0) thread 0xffff8000211f5560 (12407) exclusive kernel_lock &kernel_lock r = 0 (0xffffffff82d78a60) #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 (0xffffffff82c75c58) #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 ddb{1}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 10165 6458K 6458K 78643K 11243 0 pcb 13 8K 8K 78643K 13 0 rtable 80 2K 2K 78643K 144 0 pf 18 7K 10K 78643K 29 0 ifaddr 17 10K 10K 78643K 17 0 ifgroup 27 1K 1K 78643K 27 0 counters 46 34K 34K 78643K 46 0 ioctlops 0 0K 4K 78643K 1476 0 mount 1 1K 1K 78643K 1 0 log 0 0K 0K 78643K 4 0 vnodes 1176 74K 74K 78643K 1192 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 1K 78643K 2 0 VM map 2 1K 1K 78643K 2 0 sem 2 0K 0K 78643K 2 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1697 195K 286K 78643K 12548 0 file desc 4 9K 13K 78643K 22 0 proc 67 91K 103K 78643K 330 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 in_multi 22 1K 1K 78643K 22 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 25 122K 122K 78643K 25 0 exec 0 0K 1K 78643K 301 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 166 15K 15K 78643K 2947 0 UVM aobj 3 2K 2K 78643K 3 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 NDP 7 0K 0K 78643K 7 0 temp 1 5904K 5968K 78643K 3511 0 kqueue 12 18K 18K 78643K 25 0 SYN cache 2 16K 16K 78643K 2 0 ddb{1}> 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 22 0 19 1 0 1 1 0 8 0 rtentry 112 34 0 1 1 0 1 1 0 8 0 unpcb 144 35 0 20 1 0 1 1 0 8 0 syncache 304 5 0 5 1 0 1 1 0 8 1 tcpqe 32 145 0 145 1 1 0 1 0 8 0 tcpcb 808 8 0 5 1 0 1 1 0 8 0 arp 120 4 0 0 1 0 1 1 0 8 0 inpcb 368 37 0 31 1 0 1 1 0 8 0 nd6 136 3 0 0 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 pfstitem 24 11 0 0 1 0 1 1 0 8 0 pfstkey 128 11 0 0 1 0 1 1 0 8 0 pfstate 376 11 0 0 2 0 2 2 0 8 0 pfrule 1344 21 0 16 2 1 1 2 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 144 0 0 9 0 9 9 0 8 0 art_table 32 145 0 0 2 0 2 2 0 8 0 art_node 16 33 0 3 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1465 0 52 89 0 89 89 0 8 0 ffsino 272 1465 0 52 95 0 95 95 0 8 0 nchpl 144 1704 0 63 61 0 61 61 0 8 0 uvmvnodes 80 1479 0 0 31 0 31 31 0 8 0 vnodes 216 1479 0 0 83 0 83 83 0 8 0 namei 1024 5502 0 5502 2 0 2 2 0 8 2 percpumem 16 36 0 0 1 0 1 1 0 8 0 kstatmem 264 10 0 0 1 0 1 1 0 8 0 scxspl 216 6208 0 6208 3 2 1 2 1 8 1 plimitpl 152 28 0 19 1 0 1 1 0 8 0 sigapl 424 370 0 336 7 1 6 6 0 8 2 knotepl 120 56 0 0 2 0 2 2 0 8 0 kqueuepl 216 21 0 13 1 0 1 1 0 8 0 pipepl 320 118 0 111 2 0 2 2 0 8 1 fdescpl 496 353 0 336 4 0 4 4 0 8 1 filepl 152 1544 0 1474 4 0 4 4 0 8 1 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 19 0 9 1 0 1 1 0 8 0 pgrppl 48 19 0 9 1 0 1 1 0 8 0 ucredpl 104 71 0 59 1 0 1 1 0 8 0 zombiepl 144 336 0 336 1 0 1 1 0 8 1 processpl 1072 370 0 336 4 0 4 4 0 8 1 procpl 680 380 0 336 6 1 5 5 0 8 1 sockpl 488 94 0 70 4 0 4 4 0 8 0 mcl8k 8192 5 0 0 1 0 1 1 0 8 0 mcl4k 4096 5 0 0 1 0 1 1 0 8 0 mcl2k 2048 284 0 0 36 0 36 36 0 8 0 mtagpl 96 2 0 0 1 0 1 1 0 8 0 mbufpl 256 295 0 0 19 0 19 19 0 8 0 bufpl 288 4109 0 140 284 0 284 284 0 8 0 anonpl 24 182878 0 179028 58 2 56 56 0 186 30 amapchunkpl 152 9771 0 9384 27 0 27 27 0 158 11 amappl16 200 5095 0 5021 6 0 6 6 0 8 0 amappl15 192 14 0 14 1 1 0 1 0 8 0 amappl14 184 164 0 147 2 0 2 2 0 8 0 amappl13 176 9 0 9 1 1 0 1 0 8 0 amappl12 168 928 0 910 3 1 2 2 0 8 1 amappl11 160 57 0 43 1 0 1 1 0 8 0 amappl10 152 16 0 14 1 0 1 1 0 8 0 amappl9 144 201 0 201 1 0 1 1 0 8 1 amappl8 136 104 0 84 2 0 2 2 0 8 1 amappl7 128 61 0 54 2 0 2 2 0 8 0 amappl6 120 211 0 194 2 0 2 2 0 8 1 amappl5 112 179 0 168 1 0 1 1 0 8 0 amappl4 104 576 0 537 3 0 3 3 0 8 1 amappl3 96 2469 0 2422 3 1 2 2 0 8 0 amappl2 88 620 0 564 3 0 3 3 0 8 1 amappl1 80 10393 0 9889 23 0 23 23 0 8 11 amappl 88 2492 0 2392 4 0 4 4 0 92 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 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 2 0 0 1 0 1 1 0 8 0 uaddrrnd 24 353 0 336 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 353 0 336 1 0 1 1 0 8 0 vmmpekpl 168 9677 0 9653 2 0 2 2 0 8 0 vmmpepl 168 42581 0 41242 117 0 117 117 0 357 58 vmsppl 464 352 0 336 4 0 4 4 0 8 1 rwobjpl 56 20552 0 18175 47 0 47 47 0 8 6 pdppl 4096 714 0 672 84 22 62 66 0 8 20 pvpl 32 379714 0 371330 348 9 339 346 0 265 265 pmappl 248 352 0 336 2 0 2 2 0 8 0 extentpl 40 56 0 38 1 0 1 1 0 8 0 phpool 112 635 0 25 18 0 18 18 0 8 0 ddb{1}> machine ddbcpu 0 Stopped at x86_ipi_db+0x1e: addq $0x8,%rsp ddb{0}> trace x86_ipi_db(ffffffff82b9dff0) 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(ffffffff82c75a50) at __mp_lock+0x122 __mp_lock_spin sys/kern/kern_lock.c:116 [inline] __mp_lock(ffffffff82c75a50) at __mp_lock+0x122 sys/kern/kern_lock.c:147 yield() at yield+0x37 sys/kern/sched_bsd.c:321 uvm_pagezero_thread(ffff8000211b2558) at uvm_pagezero_thread+0x6d sys/uvm/uvm_pmemrange.c:2170 end trace frame: 0x0, count: -6 ddb{0}> machine ddbcpu 1 Stopped at db_enter+0x1c: addq $0x8,%rsp ddb{1}> trace db_enter() at db_enter+0x1c sys/arch/amd64/amd64/db_interface.c:437 witness_checkorder(ffff80002121de70,9,0) at witness_checkorder+0x10b7 witness_debugger sys/kern/subr_witness.c:2510 [inline] witness_checkorder(ffff80002121de70,9,0) at witness_checkorder+0x10b7 sys/kern/subr_witness.c:1110 mtx_enter(ffff80002121de60) at mtx_enter+0x3e sys/kern/kern_lock.c:265 single_thread_set(ffff8000211f5560,0,1) at single_thread_set+0x35a single_thread_wait sys/kern/kern_sig.c:2172 [inline] single_thread_set(ffff8000211f5560,0,1) at single_thread_set+0x35a sys/kern/kern_sig.c:2155 sigexit(ffff8000211f5560,6) at sigexit+0x90 sys/kern/kern_sig.c:1562 postsig(ffff8000211f5560,6,ffff8000212bbdf8) at postsig+0x4a9 sys/kern/kern_sig.c:1494 userret(ffff8000211f5560) at userret+0x16e sys/kern/kern_sig.c:1987 syscall(ffff8000212bbf30) at syscall+0x4e7 mi_syscall_return sys/sys/syscall_mi.h:137 [inline] syscall(ffff8000212bbf30) at syscall+0x4e7 sys/arch/amd64/amd64/trap.c:644 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xc2950459e80, count: -9 ddb{1}>