witness: lock order reversal: 1st 0xffffffff82cfb918 &sched_lock (&sched_lock) 2nd 0xffff80002121ef30 &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(ffff80002121ef30,9,0) at witness_checkorder+0x10b7 witness_debugger sys/kern/subr_witness.c:2510 [inline] witness_checkorder(ffff80002121ef30,9,0) at witness_checkorder+0x10b7 sys/kern/subr_witness.c:1110 mtx_enter(ffff80002121ef20) 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,ffff8000212a76d8) at postsig+0x4a9 sys/kern/kern_sig.c:1494 userret(ffff8000211f5560) at userret+0x16e sys/kern/kern_sig.c:1987 syscall(ffff8000212a7810) at syscall+0x4e7 mi_syscall_return sys/sys/syscall_mi.h:137 [inline] syscall(ffff8000212a7810) at syscall+0x4e7 sys/arch/amd64/amd64/trap.c:644 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xd0b507df190, count: -9 ddb{1}> show registers rdi 0x3 rsi 0xffffffff82b8e4a0 __sancov_gen_cov_switch_values.134 rbp 0xffff8000212a73e0 rbx 0x3 rdx 0x3fd rcx 0 rax 0x1 r8 0xffff8000212a7350 r9 0x8080808080808080 r10 0xf7fa211f888a2172 r11 0x1a374c6c29b9a75b r12 0xfffffd8003a0e590 r13 0 r14 0xfffffd8003a06ea0 r15 0xfffffd80031cbbc0 rip 0xffffffff810eab1c db_enter+0x1c cs 0x8 rflags 0x246 rsp 0xffff8000212a73d0 ss 0x10 db_enter+0x1c: addq $0x8,%rsp ddb{1}> show proc PROC (syz-executor.0) pid=144751 stat=onproc flags process=100000 proc=4002000 pri=32, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff8000211f52b8,0xffffffff82cfc210 process=0xffff80002121ee20 user=0xffff8000212a2000, vmspace=0xfffffd8008a16910 estcpu=36, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 11689 292002 48983 0 4 0x182000 syz-executor.0 *11689 144751 48983 0 7 0x4102000 syz-executor.0 48983 355345 13863 0 3 0x82 nanoslp syz-executor.0 13863 335598 24498 0 3 0x2000082 thrsleep syz-execprog 13863 62261 24498 0 3 0x6000082 thrsleep syz-execprog 13863 169013 24498 0 3 0x6000082 thrsleep syz-execprog 13863 297067 24498 0 3 0x6000082 thrsleep syz-execprog 13863 231040 24498 0 3 0x6000082 thrsleep syz-execprog 13863 209383 24498 0 3 0x6000082 thrsleep syz-execprog 13863 394308 24498 0 3 0x6000082 kqread syz-execprog 13863 389240 24498 0 3 0x6000082 thrsleep syz-execprog 13863 386442 24498 0 3 0x6000082 wait syz-execprog 13863 306752 24498 0 3 0x6000082 thrsleep syz-execprog 13863 86716 24498 0 3 0x6000082 thrsleep syz-execprog 24498 42504 74284 0 3 0x10008a sigsusp ksh 74284 9292 88596 0 3 0x9a kqread sshd 29938 495664 1 0 3 0x100083 ttyin getty 88596 388804 1 0 3 0x88 kqread sshd 56969 46580 66911 74 3 0x1100092 bpf pflogd 66911 403112 1 0 3 0x80 netio pflogd 32972 514910 51375 73 3 0x1100090 kqread syslogd 51375 124933 1 0 3 0x100082 netio syslogd 2340 503501 1 0 3 0x100080 kqread resolvd 71725 153277 82963 77 3 0x100092 kqread dhcpleased 14688 183077 82963 77 3 0x100092 kqread dhcpleased 82963 88972 1 0 3 0x80 kqread dhcpleased 27526 286132 0 0 3 0x14200 bored smr 43010 271103 0 0 7 0x14200 zerothread 65069 421715 0 0 3 0x14200 aiodoned aiodoned 97188 362403 0 0 3 0x14200 syncer update 21575 282965 0 0 3 0x14200 cleaner cleaner 77054 39759 0 0 3 0x14200 reaper reaper 42607 25774 0 0 3 0x14200 pgdaemon pagedaemon 95552 400143 0 0 3 0x14200 bored viomb 75236 493921 0 0 3 0x40014200 acpi0 acpi0 92234 426578 0 0 3 0x40014200 idle1 29906 494059 0 0 3 0x14200 bored softnet3 96667 285575 0 0 3 0x14200 bored softnet2 68867 397023 0 0 3 0x14200 bored softnet1 73868 16211 0 0 3 0x14200 bored softnet0 22957 6554 0 0 3 0x14200 bored systqmp 85660 392094 0 0 3 0x14200 bored systq 43346 360227 0 0 3 0x40014200 bored softclock 17960 502908 0 0 3 0x40014200 idle0 1 9937 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 (0xffffffff82cfb918) #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 11689 (syz-executor.0) thread 0xffff8000211f5560 (144751) exclusive kernel_lock &kernel_lock r = 0 (0xffffffff82c82c68) #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 (0xffffffff82cfb918) #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 25 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 299 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 167 16K 18K 78643K 2903 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 3461 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 32 208 0 208 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 5490 0 5490 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 6303 0 6303 3 2 1 2 1 8 1 plimitpl 152 28 0 19 1 0 1 1 0 8 0 sigapl 424 368 0 334 7 1 6 6 0 8 2 knotepl 120 70 0 0 3 0 3 3 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 496 351 0 334 4 0 4 4 0 8 1 filepl 152 1538 0 1468 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 144 334 0 334 1 0 1 1 0 8 1 processpl 1072 368 0 334 4 0 4 4 0 8 1 procpl 680 379 0 334 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 2 0 0 1 0 1 1 0 8 0 mcl2k 2048 257 0 0 33 0 33 33 0 8 0 mtagpl 96 2 0 0 1 0 1 1 0 8 0 mbufpl 256 276 0 0 18 0 18 18 0 8 0 bufpl 288 4117 0 148 284 0 284 284 0 8 0 anonpl 24 174076 0 170293 58 0 58 58 0 186 32 amapchunkpl 152 9668 0 9268 28 0 28 28 0 158 11 amappl16 200 4637 0 4574 5 0 5 5 0 8 0 amappl15 192 12 0 11 1 0 1 1 0 8 0 amappl14 184 139 0 127 2 0 2 2 0 8 1 amappl13 176 8 0 8 1 1 0 1 0 8 0 amappl12 168 928 0 910 3 1 2 2 0 8 1 amappl11 160 60 0 44 1 0 1 1 0 8 0 amappl10 152 28 0 25 1 0 1 1 0 8 0 amappl9 144 184 0 184 1 0 1 1 0 8 1 amappl8 136 104 0 81 2 0 2 2 0 8 1 amappl7 128 61 0 56 1 0 1 1 0 8 0 amappl6 120 191 0 172 3 1 2 3 0 8 1 amappl5 112 140 0 129 1 0 1 1 0 8 0 amappl4 104 551 0 511 3 0 3 3 0 8 1 amappl3 96 2478 0 2432 3 1 2 2 0 8 0 amappl2 88 617 0 560 3 0 3 3 0 8 1 amappl1 80 10268 0 9768 23 0 23 23 0 8 10 amappl 88 2451 0 2349 5 0 5 5 0 92 2 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 24 351 0 334 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 351 0 334 1 0 1 1 0 8 0 vmmpekpl 168 9592 0 9568 2 0 2 2 0 8 0 vmmpepl 168 41382 0 40049 119 1 118 118 0 357 60 vmsppl 464 350 0 334 4 0 4 4 0 8 1 rwobjpl 56 20005 0 17641 47 0 47 47 0 8 8 pdppl 4096 710 0 668 84 18 66 66 0 8 24 pvpl 32 368959 0 360631 367 0 367 367 0 265 291 pmappl 248 350 0 334 2 0 2 2 0 8 0 extentpl 40 56 0 38 1 0 1 1 0 8 0 phpool 112 631 0 21 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(ffffffff82be4ff0) 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(ffffffff82cfb710) at __mp_lock+0x122 __mp_lock_spin sys/kern/kern_lock.c:116 [inline] __mp_lock(ffffffff82cfb710) at __mp_lock+0x122 sys/kern/kern_lock.c:147 yield() at yield+0x37 sys/kern/sched_bsd.c:321 uvm_pagezero_thread(ffff8000211b2800) 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(ffff80002121ef30,9,0) at witness_checkorder+0x10b7 witness_debugger sys/kern/subr_witness.c:2510 [inline] witness_checkorder(ffff80002121ef30,9,0) at witness_checkorder+0x10b7 sys/kern/subr_witness.c:1110 mtx_enter(ffff80002121ef20) 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,ffff8000212a76d8) at postsig+0x4a9 sys/kern/kern_sig.c:1494 userret(ffff8000211f5560) at userret+0x16e sys/kern/kern_sig.c:1987 syscall(ffff8000212a7810) at syscall+0x4e7 mi_syscall_return sys/sys/syscall_mi.h:137 [inline] syscall(ffff8000212a7810) at syscall+0x4e7 sys/arch/amd64/amd64/trap.c:644 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xd0b507df190, count: -9 ddb{1}>