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+0xb sys/kern/subr_witness.c:1252 #7 exit1+0x6e5 sys/kern/kern_exit.c:292 #8 sys_exit+0x17 sys/kern/kern_exit.c:94 #9 syscall+0x552 mi_syscall sys/sys/syscall_mi.h:99 [inline] #9 syscall+0x552 sys/arch/amd64/amd64/trap.c:574 #10 Xsyscall+0x128 Stopped at db_enter+0x18: addq $0x8,%rsp ddb{0}> ddb{0}> set $lines = 0 ddb{0}> set $maxwidth = 0 ddb{0}> show panic the kernel did not panic ddb{0}> 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(ffff800020b39080) at schedclock+0x99 sys/kern/sched_bsd.c:547 hardclock(ffff800020bebc50) 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,ffffffff819d2606,ffffffff821abff0,0,0,ffff800020b3ab28) at Xresume_lapic_ltimer+0x26 witness_unlock(ffff800020b3ab28,ffff800020b3ab28) at witness_unlock+0xb sys/kern/subr_witness.c:1252 exit1(ffff800020b39080,0,1) at exit1+0x6e5 sys/kern/kern_exit.c:292 sys_exit(ffff800020b39080,ffff800020bebe20,ffff800020bebe90) at sys_exit+0x17 sys/kern/kern_exit.c:94 syscall(ffff800020bebf00) at syscall+0x552 mi_syscall sys/sys/syscall_mi.h:99 [inline] syscall(ffff800020bebf00) at syscall+0x552 sys/arch/amd64/amd64/trap.c:574 Xsyscall(6,1,0,1,0,7f7ffffc1c04) at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc1bd0, count: -12 ddb{0}> show registers rdi 0x3 rsi 0xffffffff82243e20 __sancov_gen_cov_switch_values.122 rbp 0xffff800020beba50 rbx 0x3 rdx 0xffffffff821abff0 cpu_info_full_primary+0x1ff0 rcx 0x3 rax 0xffffffff821abff0 cpu_info_full_primary+0x1ff0 r8 0xffffffff81da2df5 witness_checkorder+0xfd5 r9 0x5 r10 0x3 r11 0xf852b1e86fa5e5e4 r12 0xfffffd8002661340 r13 0xc r14 0xffffffff8233b1a0 w_lodata+0x4c2f0 r15 0xffffffff82346250 w_lodata+0x573a0 rip 0xffffffff819ca3d8 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800020beba40 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{0}> show proc PROC (syz-executor.1) pid=446410 stat=dead flags process=1018 proc=2000 pri=50, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffffffffffffffff,0xffffffffffffffff process=0xffff800020b3aa78 user=0xffff800020be6000, vmspace=0xfffffd807effd708 estcpu=36, cpticks=2, pctcpu=0.0 user=0, sys=1, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 87293 420919 0 0 3 0x14200 bored sosplice 90431 106044 68909 32767 2 0x10 syz-executor.0 68909 431296 52731 0 3 0x82 wait syz-executor.0 32584 282746 42077 32767 3 0x90 nanosleep syz-executor.1 42077 63674 52731 0 3 0x82 wait syz-executor.1 52731 178504 66216 0 3 0x82 thrsleep syz-fuzzer 52731 410607 66216 0 3 0x4000082 nanosleep syz-fuzzer 52731 270885 66216 0 3 0x4000082 thrsleep syz-fuzzer 52731 322073 66216 0 3 0x4000082 thrsleep syz-fuzzer 52731 140142 66216 0 3 0x4000082 kqread syz-fuzzer 52731 114256 66216 0 3 0x4000082 thrsleep syz-fuzzer 52731 387658 66216 0 3 0x4000082 thrsleep syz-fuzzer 52731 55402 66216 0 3 0x4000082 thrsleep syz-fuzzer 52731 520403 66216 0 3 0x4000082 thrsleep syz-fuzzer 52731 465176 66216 0 3 0x4000082 thrsleep syz-fuzzer 66216 247987 75556 0 3 0x10008a pause ksh 75556 282141 24810 0 3 0x92 select sshd 89601 65271 1 0 3 0x100083 ttyin getty 24810 350318 1 0 3 0x80 select sshd 44755 468487 35631 73 2 0x100090 syslogd 35631 483454 1 0 3 0x100082 netio syslogd 11652 470873 1 77 3 0x100090 poll dhclient 80885 512852 1 0 3 0x80 poll dhclient 32288 522203 0 0 3 0x14200 pgzero zerothread 13936 8971 0 0 3 0x14200 aiodoned aiodoned 73632 15854 0 0 3 0x14200 syncer update 42737 111333 0 0 3 0x14200 cleaner cleaner 5005 475141 0 0 7 0x14200 reaper 91404 340650 0 0 3 0x14200 pgdaemon pagedaemon 70774 74275 0 0 3 0x14200 bored crynlk 32187 156782 0 0 3 0x14200 bored crypto 63184 392752 0 0 3 0x40014200 acpi0 acpi0 62108 386286 0 0 3 0x40014200 idle1 39074 382011 0 0 3 0x14200 bored softnet 15741 408631 0 0 3 0x14200 bored systqmp 37563 172731 0 0 3 0x14200 bored systq 94612 34492 0 0 3 0x40014200 bored softclock 33024 378939 0 0 3 0x40014200 idle0 40072 117423 0 0 3 0x14200 bored smr 1 337267 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{0}> show all locks CPU 0: 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 tuagg+0x32 sys/kern/kern_resource.c:360 #4 exit1+0x6e5 sys/kern/kern_exit.c:292 #5 sys_exit+0x17 sys/kern/kern_exit.c:94 #6 syscall+0x552 mi_syscall sys/sys/syscall_mi.h:99 [inline] #6 syscall+0x552 sys/arch/amd64/amd64/trap.c:574 #7 Xsyscall+0x128 Process 90431 (syz-executor.0) thread 0xffff800020b38e28 (106044) exclusive rrwlock inode r = 0 (0xfffffd8069338d60) #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 (0xfffffd80693382c0) #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{0}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim Kern Lim devbuf 9458 6321K 6321K 78643K 10550 0 0 pcb 23 9K 9K 78643K 83 0 0 rtable 105 3K 3K 78643K 235 0 0 ifaddr 34 9K 9K 78643K 40 0 0 counters 39 33K 33K 78643K 39 0 0 ioctlops 0 0K 2K 78643K 18 0 0 iov 0 0K 12K 78643K 90 0 0 mount 1 1K 1K 78643K 1 0 0 vnodes 1209 76K 76K 78643K 1240 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 4 0 0 VM map 2 1K 1K 78643K 2 0 0 sem 10 0K 1K 78643K 101 0 0 dirhash 12 2K 2K 78643K 12 0 0 ACPI 1808 196K 290K 78643K 12628 0 0 file desc 6 17K 33K 78643K 311 0 0 sigio 0 0K 0K 78643K 2 0 0 proc 41 38K 70K 78643K 339 0 0 subproc 34 2K 2K 78643K 51 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 10 0 0 in_multi 33 2K 2K 78643K 46 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 48 212K 212K 78643K 48 0 0 exec 0 0K 1K 78643K 196 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 84 20K 30K 78643K 1681 0 0 UVM aobj 2 2K 2K 78643K 2 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 1 0 0 NDP 5 0K 0K 78643K 12 0 0 temp 83 2724K 2788K 78643K 3693 0 0 SYN cache 2 16K 16K 78643K 2 0 0 ddb{0}> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle arp 64 8 0 2 1 0 1 1 0 8 0 inpcbpl 280 93 0 86 1 0 1 1 0 8 0 plimitpl 152 23 0 14 1 0 1 1 0 8 0 plcache 128 20 0 0 1 0 1 1 0 8 0 rtentry 112 56 0 12 2 0 2 2 0 8 0 syncache 264 4 0 4 1 1 0 1 0 8 0 tcpcb 544 26 0 22 1 0 1 1 0 8 0 nd6 48 9 0 3 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 232 0 44 12 0 12 12 0 8 0 art_table 32 233 0 44 2 0 2 2 0 8 0 art_node 16 55 0 15 1 0 1 1 0 8 0 semupl 112 37 0 37 1 0 1 1 0 8 1 semapl 112 99 0 91 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino1pl 128 1799 0 380 46 0 46 46 0 8 0 ffsino 272 1799 0 380 95 0 95 95 0 8 0 nchpl 144 2408 0 791 61 0 61 61 0 8 0 uvmvnodes 72 1859 0 0 34 0 34 34 0 8 0 vnodes 200 1859 0 0 98 0 98 98 0 8 0 namei 1024 6128 0 6128 2 1 1 1 0 8 1 percpumem 16 30 0 0 1 0 1 1 0 8 0 scxspl 192 7049 0 7049 9 8 1 6 0 8 1 sigapl 432 479 0 464 3 1 2 3 0 8 0 futexpl 56 2216 0 2216 1 0 1 1 0 8 1 knotepl 112 79 0 60 1 0 1 1 0 8 0 kqueuepl 104 20 0 18 1 0 1 1 0 8 0 pipepl 112 370 0 351 2 1 1 1 0 8 0 fdescpl 488 480 0 465 3 0 3 3 0 8 1 filepl 152 2223 0 2127 6 1 5 5 0 8 1 lockfpl 104 245 0 245 2 1 1 1 0 8 1 lockfspl 48 119 0 119 2 1 1 1 0 8 1 sessionpl 112 18 0 8 1 0 1 1 0 8 0 pgrppl 48 18 0 8 1 0 1 1 0 8 0 ucredpl 96 445 0 436 1 0 1 1 0 8 0 zombiepl 144 465 0 464 2 1 1 1 0 8 0 processpl 888 496 0 464 4 0 4 4 0 8 0 procpl 600 887 0 845 4 0 4 4 0 8 0 srpgc 64 6 0 6 1 1 0 1 0 8 0 sosppl 128 3 0 3 1 0 1 1 0 8 1 sockpl 384 165 0 148 3 0 3 3 0 8 1 mcl12k 12288 1 0 0 1 0 1 1 0 8 0 mcl9k 9216 1 0 0 1 0 1 1 0 8 0 mcl8k 8192 2 0 0 1 0 1 1 0 8 0 mcl4k 4096 3 0 0 1 0 1 1 0 8 0 mcl2k2 2112 2 0 0 1 0 1 1 0 8 0 mcl2k 2048 122 0 0 15 0 15 15 0 8 0 mtagpl 80 1 0 0 1 0 1 1 0 8 0 mbufpl 256 181 0 0 11 0 11 11 0 8 0 bufpl 256 5935 0 1159 299 0 299 299 0 8 0 anonpl 16 43797 0 38178 29 5 24 28 0 125 0 amapchunkpl 152 2410 0 2323 11 5 6 11 0 158 2 amappl16 192 1243 0 959 17 2 15 17 0 8 0 amappl15 184 248 0 244 1 0 1 1 0 8 0 amappl14 176 153 0 150 2 1 1 1 0 8 0 amappl12 160 34 0 33 1 0 1 1 0 8 0 amappl11 152 54 0 40 1 0 1 1 0 8 0 amappl10 144 72 0 69 2 1 1 1 0 8 0 amappl9 136 570 0 567 1 0 1 1 0 8 0 amappl8 128 134 0 120 1 0 1 1 0 8 0 amappl7 120 42 0 33 1 0 1 1 0 8 0 amappl6 112 60 0 52 1 0 1 1 0 8 0 amappl5 104 138 0 129 1 0 1 1 0 8 0 amappl4 96 487 0 467 1 0 1 1 0 8 0 amappl3 88 428 0 411 1 0 1 1 0 8 0 amappl2 80 3083 0 3014 4 2 2 3 0 8 0 amappl1 72 19520 0 19083 23 13 10 19 0 8 0 amappl 80 1131 0 1096 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 1 0 0 1 0 1 1 0 8 0 uaddrrnd 24 480 0 464 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 480 0 464 1 0 1 1 0 8 0 vmmpekpl 168 7613 0 7589 2 0 2 2 0 8 0 vmmpepl 168 58558 0 57204 90 25 65 74 0 357 6 vmsppl 360 479 0 464 2 0 2 2 0 8 0 pdppl 4096 968 0 928 6 0 6 6 0 8 1 pvpl 32 208620 0 199846 104 15 89 102 0 265 15 pmappl 232 479 0 464 2 1 1 2 0 8 0 extentpl 40 41 0 26 1 0 1 1 0 8 0 phpool 112 449 0 3 13 0 13 13 0 8 0