witness: lock order reversal: 1st 0xffff800020b8d5a8 &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 __sanitizer_cov_trace_cmp4+0x3a sys/dev/kcov.c:172 #7 witness_unlock+0x10c sys/kern/subr_witness.c:1272 #8 mtx_leave+0x97 sys/kern/kern_lock.c:360 #9 exit1+0x6e5 sys/kern/kern_exit.c:292 #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(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(ffff800022e2ed40) 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,ffffffff817951cd,0,0,9,d) at Xresume_lapic_ltimer+0x26 __sanitizer_cov_trace_cmp4(d,d) at __sanitizer_cov_trace_cmp4+0x3a sys/dev/kcov.c:172 witness_unlock(ffff800020b8d5a8,8) at witness_unlock+0x10c sys/kern/subr_witness.c:1272 mtx_leave(ffff800020b8d598) 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 syscall(ffff800022e2f140) at syscall+0x614 mi_syscall_return sys/sys/syscall_mi.h:122 [inline] syscall(ffff800022e2f140) at syscall+0x614 sys/arch/amd64/amd64/trap.c:596 Xsyscall(6,4,6d97a95e0,53,0,73786b200) at Xsyscall+0x128 end of kernel end trace frame: 0x7425dd680, count: -15 ddb{1}> show registers rdi 0x3 rsi 0xffffffff821fc9e0 __sancov_gen_cov_switch_values.122 rbp 0xffff800022e2eb40 rbx 0x3 rdx 0xffff800020ab0ff0 rcx 0x3 rax 0xffff800020ab0ff0 r8 0xffffffff818c8c95 witness_checkorder+0xfd5 r9 0x5 r10 0x3 r11 0x3e3831d72ddcb211 r12 0xfffffd8002661340 r13 0xc r14 0xffffffff82336c50 w_lodata+0x4ba00 r15 0xffffffff823423e0 w_lodata+0x57190 rip 0xffffffff81a42468 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800022e2eb30 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{1}> show proc PROC (syz-executor.1) pid=197215 stat=dead flags process=1000 proc=4082000 pri=50, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffffffffffffffff,0xffffffffffffffff process=0xffff800020b8d4e8 user=0xffff800022e2a000, vmspace=0xfffffd807effd9d8 estcpu=36, cpticks=1, pctcpu=0.0 user=0, sys=1, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 39709 519278 18 0 3 0x3000 suspend syz-executor.1 39709 54816 18 0 7 0x4081000 syz-executor.1 16172 182102 0 0 3 0x14200 bored sosplice 18 169100 36460 0 3 0x82 nanosleep syz-executor.1 23118 269360 36460 0 3 0x2 biowait syz-executor.0 36460 389781 87845 0 3 0x82 thrsleep syz-fuzzer 36460 229150 87845 0 3 0x4000082 nanosleep syz-fuzzer 36460 137262 87845 0 3 0x4000082 thrsleep syz-fuzzer 36460 150926 87845 0 3 0x4000082 thrsleep syz-fuzzer 36460 474990 87845 0 3 0x4000082 thrsleep syz-fuzzer 36460 84416 87845 0 3 0x4000082 thrsleep syz-fuzzer 36460 278027 87845 0 3 0x4000082 thrsleep syz-fuzzer 36460 507854 87845 0 3 0x4000082 thrsleep syz-fuzzer 36460 60925 87845 0 3 0x4000082 kqread syz-fuzzer 36460 479539 87845 0 3 0x4000082 thrsleep syz-fuzzer 87845 44490 58996 0 3 0x10008a pause ksh 58996 284096 79221 0 3 0x92 select sshd 31337 20602 1 0 3 0x100083 ttyin getty 79221 332118 1 0 3 0x80 select sshd 10164 56960 42820 74 3 0x100092 bpf pflogd 42820 389271 1 0 3 0x80 netio pflogd 73133 502615 84764 73 2 0x100090 syslogd 84764 400184 1 0 3 0x100082 netio syslogd 61519 16809 1 77 3 0x100090 poll dhclient 33518 399781 1 0 3 0x80 poll dhclient 79169 68721 0 0 3 0x14200 pgzero zerothread 98014 413231 0 0 3 0x14200 aiodoned aiodoned 60486 356028 0 0 3 0x14200 syncer update 39699 359063 0 0 3 0x14200 cleaner cleaner 5366 420082 0 0 3 0x14200 reaper reaper 67126 93063 0 0 3 0x14200 pgdaemon pagedaemon 76075 426069 0 0 3 0x14200 bored crynlk 44966 240975 0 0 3 0x14200 bored crypto 79530 170237 0 0 3 0x40014200 acpi0 acpi0 73723 26564 0 0 3 0x40014200 idle1 67331 279626 0 0 3 0x14200 bored softnet 39059 156217 0 0 3 0x14200 bored systqmp 74990 407441 0 0 3 0x14200 bored systq 83879 229737 0 0 3 0x40014200 bored softclock 83098 171911 0 0 3 0x40014200 idle0 88314 332934 0 0 3 0x14200 bored smr 1 219968 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 (0xffff800020b8d5a8) #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 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 Process 23118 (syz-executor.0) thread 0xffff800020b159d0 (269360) exclusive rrwlock inode r = 0 (0xfffffd8066d721b8) #0 witness_lock+0x52e sys/kern/subr_witness.c:1161 #1 rw_enter+0x46d sys/kern/kern_rwlock.c:306 #2 rrw_enter+0x4f sys/kern/kern_rwlock.c:435 #3 VOP_LOCK+0x4b sys/kern/vfs_vops.c:602 #4 vn_lock+0x6e sys/kern/vfs_vnops.c:549 #5 vget+0x1c3 sys/kern/vfs_subr.c:672 #6 ufs_ihashget+0x141 sys/ufs/ufs/ufs_ihash.c:119 #7 ffs_vget+0x74 sys/ufs/ffs/ffs_vfsops.c:1323 #8 ufs_lookup+0x1575 sys/ufs/ufs/ufs_lookup.c:487 #9 VOP_LOOKUP+0x5b sys/kern/vfs_vops.c:90 #10 vfs_lookup+0x77d sys/kern/vfs_lookup.c:571 #11 namei+0x61c sys/kern/vfs_lookup.c:252 #12 dounlinkat+0x99 sys/kern/vfs_syscalls.c:1766 #13 syscall+0x552 mi_syscall sys/sys/syscall_mi.h:99 [inline] #13 syscall+0x552 sys/arch/amd64/amd64/trap.c:574 #14 Xsyscall+0x128 exclusive rrwlock inode r = 0 (0xfffffd8069a1f0a0) #0 witness_lock+0x52e sys/kern/subr_witness.c:1161 #1 rw_enter+0x46d sys/kern/kern_rwlock.c:306 #2 rrw_enter+0x4f sys/kern/kern_rwlock.c:435 #3 VOP_LOCK+0x4b sys/kern/vfs_vops.c:602 #4 vn_lock+0x6e sys/kern/vfs_vnops.c:549 #5 vfs_lookup+0xe9 sys/kern/vfs_lookup.c:422 #6 namei+0x61c sys/kern/vfs_lookup.c:252 #7 dounlinkat+0x99 sys/kern/vfs_syscalls.c:1766 #8 syscall+0x552 mi_syscall sys/sys/syscall_mi.h:99 [inline] #8 syscall+0x552 sys/arch/amd64/amd64/trap.c:574 #9 Xsyscall+0x128 ddb{1}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim Kern Lim devbuf 9492 6412K 6919K 78643K 10936 0 0 pcb 25 9K 10K 78643K 110 0 0 rtable 108 4K 4K 78643K 234 0 0 ifaddr 49 11K 12K 78643K 67 0 0 counters 39 33K 33K 78643K 39 0 0 ioctlops 0 0K 4K 78643K 1477 0 0 iov 0 0K 4K 78643K 6 0 0 mount 1 1K 1K 78643K 1 0 0 vnodes 1208 76K 76K 78643K 1375 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 5 0 0 VM map 2 1K 1K 78643K 2 0 0 sem 12 1K 1K 78643K 16 0 0 dirhash 12 2K 2K 78643K 12 0 0 ACPI 1808 196K 290K 78643K 12628 0 0 file desc 5 13K 25K 78643K 184 0 0 proc 53 50K 83K 78643K 372 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 8 0 0 in_multi 33 2K 2K 78643K 36 0 0 ether_multi 1 0K 0K 78643K 1 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 217 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 85 20K 21K 78643K 1497 0 0 UVM aobj 10 2K 2K 78643K 10 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 10 0 0 NDP 9 0K 0K 78643K 17 0 0 temp 117 2722K 2787K 78643K 3798 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 91 0 84 1 0 1 1 0 8 0 plimitpl 152 19 0 11 1 0 1 1 0 8 0 plcache 128 20 0 0 1 0 1 1 0 8 0 rtentry 112 45 0 1 2 0 2 2 0 8 0 syncache 264 4 0 4 1 1 0 1 0 8 0 tcpcb 544 30 0 26 1 0 1 1 0 8 0 nd6 48 6 0 0 1 0 1 1 0 8 0 ppxss 1128 4 0 4 1 0 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 13 0 4 1 0 1 1 0 8 0 pfstkey 112 13 0 4 1 0 1 1 0 8 0 pfstate 328 13 0 3 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 256 188 0 0 12 0 12 12 0 8 0 art_table 32 189 0 0 2 0 2 2 0 8 0 art_node 16 44 0 4 1 0 1 1 0 8 0 sysvmsgpl 40 2 0 0 1 0 1 1 0 8 0 semupl 112 1 0 1 1 1 0 1 0 8 0 semapl 112 14 0 4 1 0 1 1 0 8 0 shmpl 112 8 0 0 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino1pl 128 1725 0 306 47 0 47 47 0 8 0 ffsino 272 1725 0 306 96 0 96 96 0 8 0 nchpl 144 2149 0 512 61 0 61 61 0 8 0 uvmvnodes 72 1855 0 0 34 0 34 34 0 8 0 vnodes 200 1855 0 0 98 0 98 98 0 8 0 namei 1024 5892 0 5892 1 0 1 1 0 8 1 percpumem 16 30 0 0 1 0 1 1 0 8 0 scsiplug 64 1 0 1 1 0 1 1 0 8 1 scxspl 192 5289 0 5288 7 6 1 6 0 8 0 sigapl 432 384 0 369 3 1 2 3 0 8 0 futexpl 56 1871 0 1871 1 0 1 1 0 8 1 knotepl 112 85 0 66 1 0 1 1 0 8 0 kqueuepl 104 39 0 37 1 0 1 1 0 8 0 pipepl 112 230 0 211 2 1 1 1 0 8 0 fdescpl 488 385 0 369 3 0 3 3 0 8 0 filepl 152 2083 0 1976 5 0 5 5 0 8 0 lockfpl 104 99 0 99 2 1 1 1 0 8 1 lockfspl 48 38 0 38 2 1 1 1 0 8 1 sessionpl 112 18 0 7 1 0 1 1 0 8 0 pgrppl 48 22 0 11 1 0 1 1 0 8 0 ucredpl 96 350 0 341 1 0 1 1 0 8 0 zombiepl 144 370 0 369 2 1 1 1 0 8 0 processpl 888 401 0 369 4 0 4 4 0 8 0 procpl 600 753 0 710 4 0 4 4 0 8 0 sosppl 128 4 0 4 1 1 0 1 0 8 0 sockpl 384 174 0 155 3 0 3 3 0 8 1 mcl64k 65536 1 0 0 1 0 1 1 0 8 0 mcl16k 16384 1 0 0 1 0 1 1 0 8 0 mcl12k 12288 1 0 0 1 0 1 1 0 8 0 mcl9k 9216 2 0 0 1 0 1 1 0 8 0 mcl8k 8192 2 0 0 1 0 1 1 0 8 0 mcl4k 4096 2 0 0 1 0 1 1 0 8 0 mcl2k2 2112 1 0 0 1 0 1 1 0 8 0 mcl2k 2048 107 0 0 13 0 13 13 0 8 0 mtagpl 80 1 0 0 1 0 1 1 0 8 0 mbufpl 256 168 0 0 11 1 10 11 0 8 0 bufpl 256 5864 0 1188 293 0 293 293 0 8 0 anonpl 16 41600 0 31690 43 2 41 41 0 125 0 amapchunkpl 152 1909 0 1819 6 2 4 6 0 158 0 amappl16 192 1187 0 656 27 0 27 27 0 8 0 amappl15 184 77 0 75 1 0 1 1 0 8 0 amappl14 176 121 0 115 2 1 1 1 0 8 0 amappl12 160 14 0 13 1 0 1 1 0 8 0 amappl11 152 62 0 44 1 0 1 1 0 8 0 amappl10 144 74 0 70 1 0 1 1 0 8 0 amappl9 136 665 0 661 1 0 1 1 0 8 0 amappl8 128 210 0 196 1 0 1 1 0 8 0 amappl7 120 38 0 33 1 0 1 1 0 8 0 amappl6 112 59 0 51 1 0 1 1 0 8 0 amappl5 104 121 0 107 1 0 1 1 0 8 0 amappl4 96 482 0 457 1 0 1 1 0 8 0 amappl3 88 335 0 321 1 0 1 1 0 8 0 amappl2 80 2164 0 2093 4 2 2 3 0 8 0 amappl1 72 18086 0 17636 25 15 10 20 0 8 0 amappl 80 1002 0 966 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 9 0 0 1 0 1 1 0 8 0 uaddrrnd 24 385 0 369 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 385 0 369 1 0 1 1 0 8 0 vmmpekpl 168 7028 0 6994 2 0 2 2 0 8 0 vmmpepl 168 49178 0 47588 92 17 75 84 0 357 2 vmsppl 360 384 0 369 2 0 2 2 0 8 0 pdppl 4096 778 0 738 6 0 6 6 0 8 0 pvpl 32 154976 0 141851 113 4 109 109 0 265 1 pmappl 232 384 0 369 2 1 1 2 0 8 0 extentpl 40 41 0 26 1 0 1 1 0 8 0 phpool 112 445 0 4 13 0 13 13 0 8 0