witness: lock order reversal: 1st 0xffff800020afbc88 &pr->ps_mtx (&pr->ps_mtx) 2nd 0xffffffff82384c80 &sched_lock (&sched_lock) lock order "&sched_lock"(sched_lock) -> "&pr->ps_mtx"(mutex) first seen at: #0 witness_checkorder+0x6a7 sys/kern/subr_witness.c:877 #1 mtx_enter+0x3a sys/kern/kern_lock.c:265 #2 tuagg+0x32 sys/kern/kern_resource.c:360 #3 mi_switch+0x1c7 x86_atomic_clearbits_u32 sys/arch/amd64/compile/SYZKALLER/obj/machine/atomic.h:298 [inline] #3 mi_switch+0x1c7 sys/kern/sched_bsd.c:392 #4 sleep_finish+0x110 sys/kern/kern_synch.c:303 #5 msleep+0x1af sleep_finish_timeout sys/kern/kern_synch.c:327 [inline] #5 msleep+0x1af sleep_finish_all sys/kern/kern_synch.c:157 [inline] #5 msleep+0x1af sys/kern/kern_synch.c:220 #6 scsi_xs_sync+0x14f sys/scsi/scsi_base.c:1339 #7 scsi_start+0x86 sys/scsi/scsi_base.c:938 #8 sdopen+0x22b sys/scsi/sd.c:400 #9 spec_open+0x41c sys/kern/spec_vnops.c:158 #10 VOP_OPEN+0x6a sys/kern/vfs_vops.c:153 #11 sr_meta_native_bootprobe+0xd3 sys/dev/softraid.c:1038 #12 sr_boot_assembly+0x1aa sys/dev/softraid.c:1202 #13 sr_attach+0x183 sys/dev/softraid.c:1822 #14 config_attach+0x347 sys/kern/subr_autoconf.c:404 #15 main+0x6de sys/kern/init_main.c:483 #16 longmode_hi+0x95 lock order "&pr->ps_mtx"(mutex) -> "&sched_lock"(sched_lock) first seen at: #0 witness_checkorder+0x6a7 sys/kern/subr_witness.c:877 #1 __mp_lock+0xa1 #2 schedclock+0x99 sys/kern/sched_bsd.c:547 #3 hardclock+0x1d8 sys/kern/kern_clock.c:174 #4 lapic_clockintr+0x44 sys/arch/amd64/amd64/lapic.c:425 #5 Xresume_lapic_ltimer+0x26 #6 witness_unlock+0x20 sys/kern/subr_witness.c:1252 #7 mtx_leave+0x97 sys/kern/kern_lock.c:360 #8 exit1+0x6e5 sys/kern/kern_exit.c:292 #9 single_thread_check+0x144 sys/kern/kern_sig.c:1938 #10 userret+0x347 sys/kern/kern_sig.c:1907 #11 Xsyscall+0x156 Stopped at db_enter+0x18: 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+0x18 sys/arch/amd64/amd64/db_interface.c:398 witness_checkorder(ffffffff82384c80,9,0) at witness_checkorder+0xffc witness_debugger sys/kern/subr_witness.c:2504 [inline] witness_checkorder(ffffffff82384c80,9,0) at witness_checkorder+0xffc sys/kern/subr_witness.c:1084 __mp_lock(ffffffff82384a78) at __mp_lock+0xa1 schedclock(ffff800020b38bd0) at schedclock+0x99 sys/kern/sched_bsd.c:547 hardclock(ffff800021c2eef0) at hardclock+0x1d8 sys/kern/kern_clock.c:174 lapic_clockintr(0,0) at lapic_clockintr+0x44 sys/arch/amd64/amd64/lapic.c:425 Xresume_lapic_ltimer(9,ffffffff8123ad46,ffff800020ab0ff0,0,0,ffff800020afbc78) at Xresume_lapic_ltimer+0x26 witness_unlock(ffff800020afbc88,8) at witness_unlock+0x20 sys/kern/subr_witness.c:1252 mtx_leave(ffff800020afbc78) at mtx_leave+0x97 sys/kern/kern_lock.c:360 exit1(ffff800020b38bd0,0,3) at exit1+0x6e5 sys/kern/kern_exit.c:292 single_thread_check(ffff800020b38bd0,0) at single_thread_check+0x144 sys/kern/kern_sig.c:1938 userret(ffff800020b38bd0) at userret+0x347 sys/kern/kern_sig.c:1907 Xsyscall(6,0,2f956a26c80,53,0,2fa234cda00) at Xsyscall+0x156 end of kernel end trace frame: 0x2f9f6b8f840, count: -13 ddb{1}> show registers rdi 0x3 rsi 0xffffffff821fc9e0 __sancov_gen_cov_switch_values.122 rbp 0xffff800021c2ecf0 rbx 0x3 rdx 0xffff800020ab0ff0 rcx 0x3 rax 0xffff800020ab0ff0 r8 0xffffffff818c8c95 witness_checkorder+0xfd5 r9 0x5 r10 0x3 r11 0x15bd5bd2d2052445 r12 0xfffffd8002661340 r13 0xc r14 0xffffffff823343c0 w_lodata+0x49170 r15 0xffffffff823423e0 w_lodata+0x57190 rip 0xffffffff81a42468 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800021c2ece0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{1}> show proc PROC (syz-executor.0) pid=12031 stat=dead flags process=1000 proc=4082000 pri=77, usrpri=77, nice=20 forw=0xffffffffffffffff, list=0xffffffffffffffff,0xffffffffffffffff process=0xffff800020afbbc8 user=0xffff800021c2a000, vmspace=0xfffffd807effd9d8 estcpu=27, cpticks=1, pctcpu=0.0 user=0, sys=1, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 34733 145723 76921 0 2 0x3000 syz-executor.0 56086 186406 1 0 3 0x100083 ttyin getty 45899 196702 0 0 3 0x14200 bored sosplice 89462 471123 87076 0 3 0x82 piperd syz-executor.1 76921 462126 87076 0 3 0x82 nanosleep syz-executor.0 87076 341857 3281 0 3 0x82 thrsleep syz-fuzzer 87076 393993 3281 0 3 0x4000082 thrsleep syz-fuzzer 87076 251679 3281 0 3 0x4000082 thrsleep syz-fuzzer 87076 391285 3281 0 3 0x4000082 kqread syz-fuzzer 87076 495693 3281 0 3 0x4000082 thrsleep syz-fuzzer 87076 110064 3281 0 3 0x4000082 thrsleep syz-fuzzer 87076 20641 3281 0 3 0x4000082 thrsleep syz-fuzzer 87076 168611 3281 0 3 0x4000082 thrsleep syz-fuzzer 87076 86088 3281 0 3 0x4000082 thrsleep syz-fuzzer 87076 313928 3281 0 3 0x4000082 thrsleep syz-fuzzer 3281 151394 50887 0 3 0x10008a pause ksh 50887 289177 10079 0 3 0x92 select sshd 10079 394660 1 0 3 0x80 select sshd 3093 173330 35991 74 3 0x100092 bpf pflogd 35991 144472 1 0 3 0x80 netio pflogd 88015 486244 82563 73 2 0x100090 syslogd 82563 382898 1 0 3 0x100082 netio syslogd 87889 391624 1 77 3 0x100090 poll dhclient 93288 452040 1 0 3 0x80 poll dhclient 33002 462269 0 0 3 0x14200 pgzero zerothread 50706 23826 0 0 3 0x14200 aiodoned aiodoned 79278 303630 0 0 3 0x14200 syncer update 95846 262901 0 0 3 0x14200 cleaner cleaner 57362 30345 0 0 7 0x14200 reaper 73192 127851 0 0 3 0x14200 pgdaemon pagedaemon 43118 93373 0 0 3 0x14200 bored crynlk 11552 227750 0 0 3 0x14200 bored crypto 9263 321259 0 0 3 0x40014200 acpi0 acpi0 4644 41728 0 0 3 0x40014200 idle1 91017 240716 0 0 3 0x14200 bored softnet 14271 146759 0 0 3 0x14200 bored systqmp 74057 196872 0 0 3 0x14200 bored systq 96588 276762 0 0 3 0x40014200 bored softclock 74707 12830 0 0 3 0x40014200 idle0 17141 485824 0 0 3 0x14200 bored smr 1 462802 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{1}> show all locks CPU 1: exclusive mutex &pr->ps_mtx r = 0 (0xffff800020afbc88) #0 witness_lock+0x52e sys/kern/subr_witness.c:1161 #1 mtx_enter_try+0x102 #2 mtx_enter+0x4b sys/kern/kern_lock.c:266 #3 tuagg+0x32 sys/kern/kern_resource.c:360 #4 exit1+0x6e5 sys/kern/kern_exit.c:292 #5 single_thread_check+0x144 sys/kern/kern_sig.c:1938 #6 userret+0x347 sys/kern/kern_sig.c:1907 #7 Xsyscall+0x156 ddb{1}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim Kern Lim devbuf 9520 6414K 6866K 78643K 12472 0 0 pcb 25 9K 10K 78643K 454 0 0 rtable 112 4K 5K 78643K 415 0 0 ifaddr 59 13K 14K 78643K 157 0 0 counters 39 33K 33K 78643K 39 0 0 ioctlops 0 0K 4K 78643K 1501 0 0 iov 0 0K 16K 78643K 92 0 0 mount 1 1K 1K 78643K 1 0 0 vnodes 1207 76K 77K 78643K 1930 0 0 UFS quota 1 32K 32K 78643K 1 0 0 UFS mount 5 36K 36K 78643K 5 0 0 shm 2 1K 5K 78643K 13 0 0 VM map 2 1K 1K 78643K 2 0 0 sem 12 0K 0K 78643K 87 0 0 dirhash 12 2K 2K 78643K 12 0 0 ACPI 1808 196K 290K 78643K 12628 0 0 file desc 5 13K 25K 78643K 909 0 0 sigio 0 0K 0K 78643K 10 0 0 proc 53 50K 83K 78643K 452 0 0 subproc 32 2K 2K 78643K 34 0 0 NFS srvsock 1 0K 0K 78643K 1 0 0 NFS daemon 1 16K 16K 78643K 1 0 0 ip_moptions 0 0K 0K 78643K 80 0 0 in_multi 33 2K 2K 78643K 47 0 0 ether_multi 1 0K 0K 78643K 4 0 0 mrt 0 0K 0K 78643K 8 0 0 ISOFS mount 1 32K 32K 78643K 1 0 0 MSDOSFS mount 1 16K 16K 78643K 1 0 0 ttys 72 318K 318K 78643K 72 0 0 exec 0 0K 1K 78643K 268 0 0 pfkey data 0 0K 4K 78643K 2 0 0 pagedep 1 8K 8K 78643K 1 0 0 inodedep 1 32K 32K 78643K 1 0 0 newblk 1 0K 0K 78643K 1 0 0 VM swap 7 26K 26K 78643K 7 0 0 UVM amap 91 20K 29K 78643K 3942 0 0 UVM aobj 38 2K 2K 78643K 48 0 0 memdesc 1 4K 4K 78643K 1 0 0 crypto data 1 1K 1K 78643K 1 0 0 ip6_options 0 0K 0K 78643K 57 0 0 NDP 12 0K 0K 78643K 41 0 0 temp 159 2732K 2804K 78643K 6020 0 0 kqueue 0 0K 0K 78643K 2 0 0 SYN cache 2 16K 16K 78643K 2 0 0 ddb{1}> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle arp 64 6 0 0 1 0 1 1 0 8 0 inpcbpl 280 430 0 423 1 0 1 1 0 8 0 plimitpl 152 39 0 31 1 0 1 1 0 8 0 plcache 128 20 0 0 1 0 1 1 0 8 0 rtentry 112 51 0 7 2 0 2 2 0 8 0 syncache 264 4 0 4 1 1 0 1 0 8 0 tcpcb 544 133 0 129 1 0 1 1 0 8 0 rttmr 72 2 0 2 2 1 1 1 0 8 1 nd6 48 6 0 0 1 0 1 1 0 8 0 ppxss 1128 24 0 24 2 1 1 1 0 8 1 pfosfp 40 846 0 423 5 0 5 5 0 8 0 pfosfpen 112 1428 0 714 21 0 21 21 0 8 0 pfstitem 24 16 0 10 1 0 1 1 0 8 0 pfstkey 112 16 0 10 1 0 1 1 0 8 0 pfstate 328 16 0 10 1 0 1 1 0 8 0 pfrule 1360 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 256 189 0 0 12 0 12 12 0 8 0 art_table 32 190 0 0 2 0 2 2 0 8 0 art_node 16 46 0 6 1 0 1 1 0 8 0 sysvmsgpl 40 6 0 2 1 0 1 1 0 8 0 semupl 112 2 0 2 1 1 0 1 0 8 0 semapl 112 81 0 71 1 0 1 1 0 8 0 shmpl 112 46 0 10 2 0 2 2 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino1pl 128 2875 0 1449 47 0 47 47 0 8 0 ffsino 272 2875 0 1449 96 0 96 96 0 8 0 nchpl 144 4320 0 2686 61 0 61 61 0 8 0 uvmvnodes 72 3361 0 0 62 0 62 62 0 8 0 vnodes 200 3361 0 0 177 0 177 177 0 8 0 namei 1024 12811 0 12811 2 1 1 1 0 8 1 percpumem 16 30 0 0 1 0 1 1 0 8 0 scsiplug 64 1 0 1 1 1 0 1 0 8 0 scxspl 192 11961 0 11961 14 13 1 6 0 8 1 sigapl 432 1110 0 1095 3 1 2 3 0 8 0 futexpl 56 10336 0 10336 1 0 1 1 0 8 1 knotepl 112 225 0 206 1 0 1 1 0 8 0 kqueuepl 104 229 0 227 1 0 1 1 0 8 0 pipepl 112 656 0 637 3 2 1 2 0 8 0 fdescpl 488 1111 0 1095 3 0 3 3 0 8 0 filepl 152 6215 0 6116 6 1 5 6 0 8 1 lockfpl 104 301 0 301 2 1 1 1 0 8 1 lockfspl 48 101 0 101 2 1 1 1 0 8 1 sessionpl 112 19 0 8 1 0 1 1 0 8 0 pgrppl 48 41 0 30 1 0 1 1 0 8 0 ucredpl 96 1103 0 1094 1 0 1 1 0 8 0 zombiepl 144 1096 0 1095 2 1 1 1 0 8 0 processpl 888 1127 0 1095 4 0 4 4 0 8 0 procpl 600 3169 0 3125 4 0 4 4 0 8 0 srpgc 64 2 0 2 2 1 1 1 0 8 1 sosppl 128 10 0 10 3 3 0 1 0 8 0 sockpl 384 822 0 803 3 0 3 3 0 8 1 mcl64k 65536 9 0 0 2 0 2 2 0 8 0 mcl16k 16384 1 0 0 1 0 1 1 0 8 0 mcl12k 12288 7 0 0 1 0 1 1 0 8 0 mcl9k 9216 4 0 0 1 0 1 1 0 8 0 mcl8k 8192 1 0 0 1 0 1 1 0 8 0 mcl4k 4096 7 0 0 1 0 1 1 0 8 0 mcl2k2 2112 2 0 0 1 0 1 1 0 8 0 mcl2k 2048 121 0 0 15 0 15 15 0 8 0 mtagpl 80 1 0 0 1 0 1 1 0 8 0 mbufpl 256 155 0 0 9 0 9 9 0 8 0 bufpl 256 7575 0 1190 400 0 400 400 0 8 0 anonpl 16 100971 0 90708 70 19 51 56 0 125 8 amapchunkpl 152 6268 0 6165 15 6 9 9 0 158 4 amappl16 192 4881 0 4335 43 14 29 38 0 8 1 amappl14 176 36 0 34 2 1 1 1 0 8 0 amappl13 168 433 0 432 1 0 1 1 0 8 0 amappl12 160 8 0 7 1 0 1 1 0 8 0 amappl11 152 497 0 477 1 0 1 1 0 8 0 amappl10 144 71 0 68 1 0 1 1 0 8 0 amappl9 136 592 0 588 1 0 1 1 0 8 0 amappl8 128 149 0 133 1 0 1 1 0 8 0 amappl7 120 34 0 29 1 0 1 1 0 8 0 amappl6 112 499 0 492 1 0 1 1 0 8 0 amappl5 104 128 0 113 1 0 1 1 0 8 0 amappl4 96 1284 0 1253 2 1 1 2 0 8 0 amappl3 88 204 0 193 1 0 1 1 0 8 0 amappl2 80 8450 0 8379 4 2 2 3 0 8 0 amappl1 72 33326 0 32882 26 15 11 20 0 8 0 amappl 80 3415 0 3375 1 0 1 1 0 84 0 dma4096 4096 1 0 1 1 1 0 1 0 8 0 dma256 256 6 0 6 1 1 0 1 0 8 0 dma64 64 259 0 259 1 1 0 1 0 8 0 dma32 32 7 0 7 1 1 0 1 0 8 0 dma16 16 17 0 17 1 1 0 1 0 8 0 aobjpl 64 47 0 10 1 0 1 1 0 8 0 uaddrrnd 24 1111 0 1095 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 1111 0 1095 1 0 1 1 0 8 0 vmmpekpl 168 13110 0 13080 2 0 2 2 0 8 0 vmmpepl 168 124205 0 122605 110 35 75 85 0 357 3 vmsppl 360 1110 0 1095 2 0 2 2 0 8 0 pdppl 4096 2230 0 2190 6 0 6 6 0 8 0 pvpl 32 322709 0 309236 170 33 137 143 0 265 28 pmappl 232 1110 0 1095 2 1 1 2 0 8 0 extentpl 40 41 0 26 1 0 1 1 0 8 0 phpool 112 554 0 4 16 0 16 16 0 8 0