login: witness: lock order reversal: 1st 0xffff800020b3ab38 &pr->ps_mtx (&pr->ps_mtx) 2nd 0xffffffff8236e2f8 &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+0xb5 sys/kern/subr_witness.c:1270 #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(ffffffff8236e2f8,9,0) at witness_checkorder+0xffc witness_debugger sys/kern/subr_witness.c:2504 [inline] witness_checkorder(ffffffff8236e2f8,9,0) at witness_checkorder+0xffc sys/kern/subr_witness.c:1084 __mp_lock(ffffffff8236e0f0) at __mp_lock+0xa1 schedclock(ffff800020b38720) at schedclock+0x99 sys/kern/sched_bsd.c:547 hardclock(ffff800020becb70) 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(9,1,0,0,ffffffff82243da0,ffff800020ab0ff0) at Xresume_lapic_ltimer+0x26 witness_unlock(ffff800020b3ab38,8) at witness_unlock+0xb5 sys/kern/subr_witness.c:1270 mtx_leave(ffff800020b3ab28) at mtx_leave+0x97 sys/kern/kern_lock.c:360 sched_exit(ffff800020b38720) at sched_exit+0x112 sys/kern/kern_sched.c:225 exit1(ffff800020b38720,0,3) at exit1+0x8bf sys/kern/kern_exit.c:349 single_thread_check(ffff800020b38720,0) at single_thread_check+0x144 sys/kern/kern_sig.c:1938 userret(ffff800020b38720) at userret+0x347 sys/kern/kern_sig.c:1907 syscall(ffff800020becf90) at syscall+0x614 mi_syscall_return sys/sys/syscall_mi.h:122 [inline] syscall(ffff800020becf90) at syscall+0x614 sys/arch/amd64/amd64/trap.c:596 Xsyscall(6,4,d19c2455720,53,0,d1a4d4d2c00) at Xsyscall+0x128 end of kernel end trace frame: 0xd19b961f7f0, count: -15 ddb{1}> show registers rdi 0x3 rsi 0xffffffff82243e20 __sancov_gen_cov_switch_values.122 rbp 0xffff800020bec970 rbx 0x3 rdx 0xffff800020ab0ff0 rcx 0x3 rax 0xffff800020ab0ff0 r8 0xffffffff81da2df5 witness_checkorder+0xfd5 r9 0x5 r10 0x3 r11 0x51c7f1b4fdeeafca r12 0xfffffd8002661340 r13 0xc r14 0xffffffff8233b250 w_lodata+0x4c3a0 r15 0xffffffff82346040 w_lodata+0x57190 rip 0xffffffff819ca3d8 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800020bec960 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{1}> show proc PROC (syz-executor.1) pid=293313 stat=dead flags process=401010 proc=4082000 pri=50, usrpri=71, nice=20 forw=0xffffffffffffffff, list=0xffffffffffffffff,0xffffffffffffffff process=0xffff800020b3aa78 user=0xffff800020be8000, vmspace=0xfffffd807effd438 estcpu=36, cpticks=1, pctcpu=0.0 user=0, sys=1, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 66847 47145 87351 32767 2 0x403010 syz-executor.1 87351 198819 46785 32767 3 0x90 nanosleep syz-executor.1 46785 21929 74462 0 3 0x82 wait syz-executor.1 3754 212256 0 0 3 0x14200 bored sosplice 74462 336461 70524 0 3 0x82 kqread syz-fuzzer 74462 425803 70524 0 3 0x4000082 nanosleep syz-fuzzer 74462 422077 70524 0 3 0x4000082 thrsleep syz-fuzzer 74462 56872 70524 0 3 0x4000082 thrsleep syz-fuzzer 74462 19981 70524 0 3 0x4000082 thrsleep syz-fuzzer 74462 361235 70524 0 3 0x4000082 thrsleep syz-fuzzer 74462 19286 70524 0 3 0x4000082 thrsleep syz-fuzzer 74462 241107 70524 0 3 0x4000082 thrsleep syz-fuzzer 74462 152361 70524 0 3 0x4000082 thrsleep syz-fuzzer 74462 460939 70524 0 3 0x4000082 thrsleep syz-fuzzer 70524 69126 53187 0 3 0x10008a pause ksh 53187 159940 5001 0 3 0x92 select sshd 74092 77403 1 0 3 0x100083 ttyin getty 5001 412813 1 0 3 0x80 select sshd 79075 70070 71439 73 2 0x100090 syslogd 71439 454188 1 0 3 0x100082 netio syslogd 92624 506953 1 77 3 0x100090 poll dhclient 17773 506201 1 0 3 0x80 poll dhclient 51017 351060 0 0 3 0x14200 pgzero zerothread 35418 108251 0 0 3 0x14200 aiodoned aiodoned 7700 89964 0 0 3 0x14200 syncer update 90547 310243 0 0 3 0x14200 cleaner cleaner 9461 476554 0 0 7 0x14200 reaper 37588 109828 0 0 3 0x14200 pgdaemon pagedaemon 57881 451949 0 0 3 0x14200 bored crynlk 53791 290553 0 0 3 0x14200 bored crypto 94296 262666 0 0 3 0x40014200 acpi0 acpi0 65801 358460 0 0 3 0x40014200 idle1 72062 92705 0 0 3 0x14200 bored softnet 91324 513904 0 0 3 0x14200 bored systqmp 73479 330528 0 0 3 0x14200 bored systq 44820 367691 0 0 3 0x40014200 bored softclock 47492 108875 0 0 3 0x40014200 idle0 62492 256075 0 0 3 0x14200 bored smr 1 367546 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 (0xffff800020b3ab38) #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 9454 6319K 6321K 78643K 10571 0 0 pcb 23 9K 11K 78643K 253 0 0 rtable 83 2K 3K 78643K 427 0 0 ifaddr 28 8K 9K 78643K 65 0 0 counters 39 33K 33K 78643K 39 0 0 ioctlops 0 0K 2K 78643K 26 0 0 iov 0 0K 16K 78643K 25 0 0 mount 1 1K 1K 78643K 1 0 0 vnodes 1209 76K 76K 78643K 1377 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 7 0 0 VM map 2 1K 1K 78643K 2 0 0 sem 12 0K 0K 78643K 36 0 0 dirhash 12 2K 2K 78643K 12 0 0 ACPI 1808 196K 290K 78643K 12628 0 0 file desc 5 13K 33K 78643K 423 0 0 sigio 0 0K 0K 78643K 6 0 0 proc 41 38K 70K 78643K 533 0 0 subproc 17 1K 2K 78643K 119 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 42 0 0 in_multi 22 1K 2K 78643K 101 0 0 ether_multi 1 0K 0K 78643K 3 0 0 ISOFS mount 1 32K 32K 78643K 1 0 0 MSDOSFS mount 1 16K 16K 78643K 1 0 0 ttys 54 238K 238K 78643K 54 0 0 exec 0 0K 1K 78643K 269 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 77 12K 29K 78643K 2168 0 0 UVM aobj 23 2K 2K 78643K 23 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 20 0 0 NDP 4 0K 0K 78643K 24 0 0 temp 69 2722K 2790K 78643K 4468 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 16 0 12 1 0 1 1 0 8 0 inpcbpl 280 214 0 207 1 0 1 1 0 8 0 plimitpl 152 43 0 36 1 0 1 1 0 8 0 plcache 128 20 0 0 1 0 1 1 0 8 0 rtentry 112 100 0 67 2 0 2 2 0 8 0 syncache 264 4 0 4 1 1 0 1 0 8 0 tcpcb 544 72 0 68 1 0 1 1 0 8 0 nd6 48 21 0 18 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 408 0 264 12 0 12 12 0 8 0 art_table 32 409 0 264 2 0 2 2 0 8 0 art_node 16 99 0 69 1 0 1 1 0 8 0 semapl 112 34 0 24 1 0 1 1 0 8 0 shmpl 112 21 0 0 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino1pl 128 1886 0 465 47 0 47 47 0 8 0 ffsino 272 1886 0 465 96 0 96 96 0 8 0 nchpl 144 2603 0 992 61 0 61 61 0 8 0 uvmvnodes 72 2014 0 0 37 0 37 37 0 8 0 vnodes 200 2014 0 0 106 0 106 106 0 8 0 namei 1024 7709 0 7709 2 1 1 1 0 8 1 percpumem 16 30 0 0 1 0 1 1 0 8 0 scxspl 192 7128 0 7128 11 9 2 6 0 8 2 sigapl 432 579 0 566 3 1 2 3 0 8 0 futexpl 56 3678 0 3678 1 0 1 1 0 8 1 knotepl 112 278 0 265 1 0 1 1 0 8 0 kqueuepl 104 111 0 109 1 0 1 1 0 8 0 pipepl 112 420 0 405 3 2 1 2 0 8 0 fdescpl 488 580 0 566 3 0 3 3 0 8 1 filepl 152 3367 0 3293 8 3 5 7 0 8 1 lockfpl 104 97 0 97 2 1 1 1 0 8 1 lockfspl 48 29 0 29 2 1 1 1 0 8 1 sessionpl 112 22 0 13 1 0 1 1 0 8 0 pgrppl 48 24 0 15 1 0 1 1 0 8 0 ucredpl 96 820 0 812 1 0 1 1 0 8 0 zombiepl 144 567 0 566 2 1 1 1 0 8 0 processpl 888 596 0 566 4 0 4 4 0 8 0 procpl 600 1290 0 1248 4 0 4 4 0 8 0 srpgc 64 36 0 36 2 1 1 1 0 8 1 sosppl 128 13 0 13 2 1 1 1 0 8 1 sockpl 384 456 0 439 4 1 3 4 0 8 1 mcl12k 12288 3 0 0 1 0 1 1 0 8 0 mcl9k 9216 2 0 0 1 0 1 1 0 8 0 mcl8k 8192 3 0 0 1 0 1 1 0 8 0 mcl4k 4096 5 0 0 1 0 1 1 0 8 0 mcl2k 2048 112 0 0 13 0 13 13 0 8 0 mtagpl 80 1 0 0 1 0 1 1 0 8 0 mbufpl 256 198 0 0 12 0 12 12 0 8 0 bufpl 256 6341 0 1159 324 0 324 324 0 8 0 anonpl 16 58982 0 53829 36 9 27 33 0 125 2 amapchunkpl 152 3902 0 3816 11 7 4 9 0 158 0 amappl16 192 1714 0 1425 19 2 17 17 0 8 2 amappl15 184 194 0 192 1 0 1 1 0 8 0 amappl14 176 168 0 166 2 1 1 1 0 8 0 amappl12 160 135 0 134 1 0 1 1 0 8 0 amappl11 152 75 0 61 1 0 1 1 0 8 0 amappl10 144 104 0 101 2 1 1 1 0 8 0 amappl9 136 624 0 622 1 0 1 1 0 8 0 amappl8 128 184 0 167 1 0 1 1 0 8 0 amappl7 120 59 0 49 1 0 1 1 0 8 0 amappl6 112 57 0 51 1 0 1 1 0 8 0 amappl5 104 263 0 253 1 0 1 1 0 8 0 amappl4 96 629 0 607 1 0 1 1 0 8 0 amappl3 88 339 0 326 1 0 1 1 0 8 0 amappl2 80 3544 0 3482 4 2 2 3 0 8 0 amappl1 72 22577 0 22148 23 13 10 19 0 8 0 amappl 80 1596 0 1563 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 22 0 0 1 0 1 1 0 8 0 uaddrrnd 24 580 0 566 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 580 0 566 1 0 1 1 0 8 0 vmmpekpl 168 8693 0 8669 2 0 2 2 0 8 0 vmmpepl 168 70491 0 69209 88 22 66 74 0 357 10 vmsppl 360 579 0 566 2 0 2 2 0 8 0 pdppl 4096 1168 0 1132 6 0 6 6 0 8 1 pvpl 32 207465 0 199248 105 17 88 102 0 265 13 pmappl 232 579 0 566 2 1 1 2 0 8 0 extentpl 40 41 0 26 1 0 1 1 0 8 0 phpool 112 474 0 3 14 0 14 14 0 8 0