witness: lock order reversal: 1st 0xffff800020b8ceb8 &pr->ps_mtx (&pr->ps_mtx) 2nd 0xffffffff8236c9d8 &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+0x1b sys/kern/subr_witness.c:1252 #7 mtx_leave+0x97 sys/kern/kern_lock.c:360 #8 sched_exit+0x112 sys/kern/kern_sched.c:225 #9 exit1+0x8bf sys/kern/kern_exit.c:349 #10 single_thread_check+0x144 sys/kern/kern_sig.c:1938 #11 userret+0x347 sys/kern/kern_sig.c:1907 #12 syscall+0x614 mi_syscall_return sys/sys/syscall_mi.h:122 [inline] #12 syscall+0x614 sys/arch/amd64/amd64/trap.c:596 #13 Xsyscall+0x128 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(ffffffff8236c9d8,9,0) at witness_checkorder+0xffc witness_debugger sys/kern/subr_witness.c:2504 [inline] witness_checkorder(ffffffff8236c9d8,9,0) at witness_checkorder+0xffc sys/kern/subr_witness.c:1084 __mp_lock(ffffffff8236c7d0) at __mp_lock+0xa1 schedclock(ffff800020b38270) at schedclock+0x99 sys/kern/sched_bsd.c:547 hardclock(ffff80002502d0f0) 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,ffffffff81e84f16,ffff800020ab0ff0,0,0,ffff800020b8cea8) at Xresume_lapic_ltimer+0x26 witness_unlock(ffff800020b8ceb8,8) at witness_unlock+0x1b sys/kern/subr_witness.c:1252 mtx_leave(ffff800020b8cea8) at mtx_leave+0x97 sys/kern/kern_lock.c:360 sched_exit(ffff800020b38270) at sched_exit+0x112 sys/kern/kern_sched.c:225 exit1(ffff800020b38270,0,3) at exit1+0x8bf sys/kern/kern_exit.c:349 single_thread_check(ffff800020b38270,0) at single_thread_check+0x144 sys/kern/kern_sig.c:1938 userret(ffff800020b38270) at userret+0x347 sys/kern/kern_sig.c:1907 syscall(ffff80002502d4d0) at syscall+0x614 mi_syscall_return sys/sys/syscall_mi.h:122 [inline] syscall(ffff80002502d4d0) at syscall+0x614 sys/arch/amd64/amd64/trap.c:596 Xsyscall(6,4,1b0af45a340,53,0,1b0af45fa00) at Xsyscall+0x128 end of kernel end trace frame: 0x1b141d515e0, count: -15 ddb{1}> show registers rdi 0x3 rsi 0xffffffff821c7a20 __sancov_gen_cov_switch_values.122 rbp 0xffff80002502cef0 rbx 0x3 rdx 0xffff800020ab0ff0 rcx 0x3 rax 0xffff800020ab0ff0 r8 0xffffffff813b9985 witness_checkorder+0xfd5 r9 0x5 r10 0x3 r11 0xa8dc6355303a5e9e r12 0xfffffd8002662340 r13 0xc r14 0xffffffff82306df0 w_lodata+0x457b0 r15 0xffffffff823189e0 w_lodata+0x573a0 rip 0xffffffff81e8beb8 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80002502cee0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{1}> show proc PROC (syz-executor.0) pid=408603 stat=dead flags process=1010 proc=4082000 pri=50, usrpri=81, nice=20 forw=0xffffffffffffffff, list=0xffffffffffffffff,0xffffffffffffffff process=0xffff800020b8cdf8 user=0xffff800025028000, vmspace=0xfffffd807effe168 estcpu=36, cpticks=1, pctcpu=0.0 user=0, sys=1, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 64971 145350 69047 32767 3 0x3010 suspend syz-executor.0 64971 347327 69047 32767 7 0x4081010 syz-executor.0 69047 154904 67668 32767 3 0x90 nanosleep syz-executor.0 67668 365536 40997 0 3 0x82 wait syz-executor.0 80403 21992 0 0 3 0x14200 bored sosplice 40997 27591 81225 0 3 0x82 thrsleep syz-fuzzer 40997 461463 81225 0 3 0x4000082 nanosleep syz-fuzzer 40997 258554 81225 0 3 0x4000082 thrsleep syz-fuzzer 40997 420985 81225 0 3 0x4000082 thrsleep syz-fuzzer 40997 228721 81225 0 3 0x4000082 thrsleep syz-fuzzer 40997 30682 81225 0 3 0x4000082 thrsleep syz-fuzzer 40997 172922 81225 0 3 0x4000082 thrsleep syz-fuzzer 40997 31529 81225 0 3 0x4000082 thrsleep syz-fuzzer 40997 392568 81225 0 3 0x4000082 kqread syz-fuzzer 40997 220346 81225 0 3 0x4000082 thrsleep syz-fuzzer 81225 238882 43609 0 3 0x10008a pause ksh 43609 255116 88345 0 3 0x92 select sshd 79106 43508 1 0 3 0x100083 ttyin getty 88345 37000 1 0 3 0x80 select sshd 79602 442480 89710 73 2 0x100090 syslogd 89710 154846 1 0 3 0x100082 netio syslogd 63916 101615 1 77 3 0x100090 poll dhclient 92519 311554 1 0 3 0x80 poll dhclient 2171 205404 0 0 3 0x14200 pgzero zerothread 22434 220969 0 0 3 0x14200 aiodoned aiodoned 40769 198864 0 0 3 0x14200 syncer update 86404 73428 0 0 3 0x14200 cleaner cleaner 33309 238365 0 0 3 0x14200 reaper reaper 9151 265443 0 0 3 0x14200 pgdaemon pagedaemon 48808 189461 0 0 3 0x14200 bored crynlk 11652 52716 0 0 3 0x14200 bored crypto 98763 370600 0 0 3 0x40014200 acpi0 acpi0 97525 333769 0 0 3 0x40014200 idle1 11460 56130 0 0 3 0x14200 bored softnet 82907 458988 0 0 3 0x14200 bored systqmp 12710 170579 0 0 3 0x14200 bored systq 86331 323198 0 0 3 0x40014200 bored softclock 96448 455325 0 0 3 0x40014200 idle0 73313 323853 0 0 3 0x14200 bored smr 1 224162 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 (0xffff800020b8ceb8) #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 sched_exit+0xa5 sys/kern/kern_sched.c:224 #4 exit1+0x8bf sys/kern/kern_exit.c:349 #5 single_thread_check+0x144 sys/kern/kern_sig.c:1938 #6 userret+0x347 sys/kern/kern_sig.c:1907 #7 syscall+0x614 mi_syscall_return sys/sys/syscall_mi.h:122 [inline] #7 syscall+0x614 sys/arch/amd64/amd64/trap.c:596 #8 Xsyscall+0x128 ddb{1}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim Kern Lim devbuf 9456 6319K 6321K 78643K 10903 0 0 pcb 23 9K 11K 78643K 2065 0 0 rtable 83 2K 3K 78643K 3384 0 0 ifaddr 30 11K 12K 78643K 472 0 0 counters 39 33K 33K 78643K 39 0 0 ioctlops 0 0K 2K 78643K 152 0 0 iov 0 0K 28K 78643K 282 0 0 mount 1 1K 1K 78643K 1 0 0 vnodes 1209 76K 76K 78643K 3182 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 45 0 0 VM map 2 1K 1K 78643K 2 0 0 sem 12 0K 0K 78643K 250 0 0 dirhash 12 2K 2K 78643K 12 0 0 ACPI 1808 196K 290K 78643K 12628 0 0 file desc 5 13K 33K 78643K 4279 0 0 sigio 0 0K 0K 78643K 57 0 0 proc 41 38K 70K 78643K 3584 0 0 subproc 17 1K 2K 78643K 1241 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 495 0 0 in_multi 22 1K 2K 78643K 943 0 0 ether_multi 1 0K 0K 78643K 23 0 0 ISOFS mount 1 32K 32K 78643K 1 0 0 MSDOSFS mount 1 16K 16K 78643K 1 0 0 ttys 66 291K 291K 78643K 66 0 0 exec 0 0K 1K 78643K 1285 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 81 12K 29K 78643K 14881 0 0 UVM aobj 130 4K 4K 78643K 138 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 201 0 0 NDP 4 0K 0K 78643K 222 0 0 temp 97 2733K 2803K 78643K 20138 0 0 kqueue 0 0K 0K 78643K 48 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 64 148 0 144 1 0 1 1 0 8 0 inpcbpl 280 1982 0 1975 1 0 1 1 0 8 0 plimitpl 152 328 0 321 1 0 1 1 0 8 0 plcache 128 20 0 0 1 0 1 1 0 8 0 rtentry 112 826 0 793 2 0 2 2 0 8 0 syncache 264 4 0 4 1 1 0 1 0 8 0 tcpcb 544 790 0 786 1 0 1 1 0 8 0 nd6 48 219 0 216 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 3369 0 3222 14 2 12 13 0 8 1 art_table 32 3370 0 3222 2 0 2 2 0 8 0 art_node 16 825 0 795 1 0 1 1 0 8 0 sysvmsgpl 40 29 0 9 1 0 1 1 0 8 0 semapl 112 248 0 238 1 0 1 1 0 8 0 shmpl 112 136 0 8 4 0 4 4 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino1pl 128 5996 0 4508 49 0 49 49 0 8 0 ffsino 272 5996 0 4508 100 0 100 100 0 8 0 nchpl 144 11112 0 9497 61 0 61 61 0 8 0 uvmvnodes 72 5926 0 0 108 0 108 108 0 8 0 vnodes 200 5926 0 0 312 0 312 312 0 8 0 namei 1024 42424 0 42424 2 1 1 1 0 8 1 percpumem 16 30 0 0 1 0 1 1 0 8 0 scxspl 192 30968 0 30968 19 18 1 6 0 8 1 sigapl 432 4237 0 4224 6 4 2 3 0 8 0 futexpl 56 34617 0 34617 1 0 1 1 0 8 1 knotepl 112 2292 0 2279 1 0 1 1 0 8 0 kqueuepl 104 938 0 936 1 0 1 1 0 8 0 pipepl 112 2648 0 2635 8 7 1 2 0 8 0 fdescpl 488 4238 0 4224 3 0 3 3 0 8 1 filepl 152 24734 0 24662 10 5 5 7 0 8 1 lockfpl 104 843 0 843 5 4 1 1 0 8 1 lockfspl 48 266 0 266 5 4 1 1 0 8 1 sessionpl 112 88 0 79 1 0 1 1 0 8 0 pgrppl 48 131 0 122 1 0 1 1 0 8 0 ucredpl 96 7324 0 7316 1 0 1 1 0 8 0 zombiepl 144 4225 0 4224 2 1 1 1 0 8 0 processpl 888 4254 0 4224 4 0 4 4 0 8 0 procpl 600 11192 0 11151 5 1 4 5 0 8 0 srpgc 64 432 0 432 11 10 1 1 0 8 1 sosppl 128 67 0 67 14 14 0 1 0 8 0 sockpl 384 4121 0 4104 5 2 3 4 0 8 1 mcl64k 65536 18 0 0 3 0 3 3 0 8 0 mcl16k 16384 8 0 0 1 0 1 1 0 8 0 mcl12k 12288 17 0 0 2 0 2 2 0 8 0 mcl9k 9216 17 0 0 2 0 2 2 0 8 0 mcl8k 8192 17 0 0 3 0 3 3 0 8 0 mcl4k 4096 8 0 0 1 0 1 1 0 8 0 mcl2k2 2112 6 0 0 1 0 1 1 0 8 0 mcl2k 2048 128 0 0 15 0 15 15 0 8 0 mtagpl 80 1 0 0 1 0 1 1 0 8 0 mbufpl 256 345 0 0 13 0 13 13 0 8 0 bufpl 256 12052 0 5047 439 0 439 439 0 8 0 anonpl 16 452768 0 447470 129 88 41 43 0 125 11 amapchunkpl 152 33246 0 33163 78 69 9 18 0 158 5 amappl16 192 18270 0 17951 138 113 25 30 0 8 8 amappl15 184 1103 0 1103 6 6 0 1 0 8 0 amappl14 176 1447 0 1444 2 1 1 1 0 8 0 amappl13 168 623 0 623 9 9 0 1 0 8 0 amappl12 160 278 0 276 1 0 1 1 0 8 0 amappl11 152 537 0 521 1 0 1 1 0 8 0 amappl10 144 477 0 477 10 9 1 1 0 8 1 amappl9 136 1730 0 1727 1 0 1 1 0 8 0 amappl8 128 1161 0 1138 3 2 1 2 0 8 0 amappl7 120 600 0 592 1 0 1 1 0 8 0 amappl6 112 403 0 390 1 0 1 1 0 8 0 amappl5 104 816 0 805 1 0 1 1 0 8 0 amappl4 96 3511 0 3488 1 0 1 1 0 8 0 amappl3 88 1973 0 1961 1 0 1 1 0 8 0 amappl2 80 27965 0 27900 4 2 2 3 0 8 0 amappl1 72 120626 0 120217 26 17 9 19 0 8 0 amappl 80 12559 0 12527 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 64 137 0 8 3 0 3 3 0 8 0 uaddrrnd 24 4238 0 4224 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 4238 0 4224 1 0 1 1 0 8 0 vmmpekpl 168 37214 0 37191 2 0 2 2 0 8 0 vmmpepl 168 476105 0 474806 152 75 77 78 0 357 14 vmsppl 360 4237 0 4224 2 0 2 2 0 8 0 pdppl 4096 8484 0 8448 6 0 6 6 0 8 1 pvpl 32 1225809 0 1217412 270 158 112 120 0 265 29 pmappl 232 4237 0 4224 6 5 1 2 0 8 0 extentpl 40 41 0 26 1 0 1 1 0 8 0 phpool 112 604 0 5 18 0 18 18 0 8 0