witness: acquiring duplicate lock of same type: "&sc->sc_lock" 1st wsmuxlk @ /syzkaller/managers/multicore/kernel/sys/dev/wscons/wsmux.c:626 2nd wsmuxlk @ /syzkaller/managers/multicore/kernel/sys/dev/wscons/wsmux.c:242 Starting stack trace... witness_checkorder(ffff800002b499d0,1,ffffffff81f354ca,f2,0) at witness_checkorder+0xe14 witness_debugger sys/kern/subr_witness.c:2650 [inline] witness_checkorder(ffff800002b499d0,1,ffffffff81f354ca,f2,0) at witness_checkorder+0xe14 sys/kern/subr_witness.c:926 _rw_enter_read(ffff800002b499c0,ffffffff81f354ca,f2) at _rw_enter_read+0x80 sys/kern/kern_rwlock.c:102 wsmux_mux_open(ffff800002b49900,ffff800000026d50) at wsmux_mux_open+0x82 wsmux_do_open sys/dev/wscons/wsmux.c:243 [inline] wsmux_mux_open(ffff800002b49900,ffff800000026d50) at wsmux_mux_open+0x82 sys/dev/wscons/wsmux.c:225 wsmux_attach_sc(ffff800000026d00,ffff800002b49900) at wsmux_attach_sc+0x180 sys/dev/wscons/wsmux.c:667 VOP_IOCTL(fffffd8067147d38,80085761,ffff800020c499f0,43,fffffd807f7c7900,ffff800020b424c8) at VOP_IOCTL+0x9a sys/kern/vfs_vops.c:290 vn_ioctl(fffffd807c38f868,80085761,ffff800020c499f0,ffff800020b424c8) at vn_ioctl+0xc9 sys/kern/vfs_vnops.c:512 sys_ioctl(ffff800020b424c8,ffff800020c49b38,ffff800020c49b20) at sys_ioctl+0x646 syscall(ffff800020c49bd0) at syscall+0x5ac mi_syscall sys/sys/syscall_mi.h:99 [inline] syscall(ffff800020c49bd0) at syscall+0x5ac sys/arch/amd64/amd64/trap.c:574 Xsyscall(6,0,ffffffffffffff86,0,3,8fc6d2f2010) at Xsyscall+0x128 end of kernel end trace frame: 0x8fef8fb6e60, count: 248 End of stack trace. 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:399 witness_checkorder(ffff800002b499d0,1,ffffffff81f354ca,f2,0) at witness_checkorder+0xe19 witness_debugger sys/kern/subr_witness.c:2650 [inline] witness_checkorder(ffff800002b499d0,1,ffffffff81f354ca,f2,0) at witness_checkorder+0xe19 sys/kern/subr_witness.c:926 _rw_enter_read(ffff800002b499c0,ffffffff81f354ca,f2) at _rw_enter_read+0x80 sys/kern/kern_rwlock.c:102 wsmux_mux_open(ffff800002b49900,ffff800000026d50) at wsmux_mux_open+0x82 wsmux_do_open sys/dev/wscons/wsmux.c:243 [inline] wsmux_mux_open(ffff800002b49900,ffff800000026d50) at wsmux_mux_open+0x82 sys/dev/wscons/wsmux.c:225 wsmux_attach_sc(ffff800000026d00,ffff800002b49900) at wsmux_attach_sc+0x180 sys/dev/wscons/wsmux.c:667 VOP_IOCTL(fffffd8067147d38,80085761,ffff800020c499f0,43,fffffd807f7c7900,ffff800020b424c8) at VOP_IOCTL+0x9a sys/kern/vfs_vops.c:290 vn_ioctl(fffffd807c38f868,80085761,ffff800020c499f0,ffff800020b424c8) at vn_ioctl+0xc9 sys/kern/vfs_vnops.c:512 sys_ioctl(ffff800020b424c8,ffff800020c49b38,ffff800020c49b20) at sys_ioctl+0x646 syscall(ffff800020c49bd0) at syscall+0x5ac mi_syscall sys/sys/syscall_mi.h:99 [inline] syscall(ffff800020c49bd0) at syscall+0x5ac sys/arch/amd64/amd64/trap.c:574 Xsyscall(6,0,ffffffffffffff86,0,3,8fc6d2f2010) at Xsyscall+0x128 end of kernel end trace frame: 0x8fef8fb6e60, count: -10 ddb{0}> show registers rdi 0 rsi 0x3ffff acpi_pdirpa+0x2be67 rbp 0xffff800020c49620 rbx 0x3 rdx 0x40000 acpi_pdirpa+0x2be68 rcx 0xffff800002b4a000 rax 0xffff800001948780 r8 0xffffffff81316553 kprintf+0x183 r9 0x1 r10 0x25 r11 0x78e9c3e16df9df9f r12 0xffffffff81f354ca substchar+0x955e r13 0xf2 r14 0xffffffff81f25297 apollo_udma33_tim+0x16e4 r15 0xffffffff81f354ca substchar+0x955e rip 0xffffffff81264218 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800020c49610 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{0}> show proc PROC (syz-executor.1) pid=28374 stat=onproc flags process=0 proc=4000000 pri=86, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffff800020b43530,0xffffffff82334d38 process=0xffff800020b44d30 user=0xffff800020c44000, vmspace=0xfffffd807f00d9d8 estcpu=36, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 33189 470300 81395 0 2 0 syz-executor.1 *33189 28374 81395 0 7 0x4000000 syz-executor.1 59445 4493 27999 0 3 0x80 nanosleep syz-executor.0 59445 137495 27999 0 3 0x4000080 poll syz-executor.0 59445 164088 27999 0 3 0x4000080 fsleep syz-executor.0 3124 262473 0 0 3 0x14200 bored sosplice 81395 365260 31919 0 3 0x82 nanosleep syz-executor.1 27999 209135 31919 0 3 0x82 nanosleep syz-executor.0 31919 254355 4350 0 3 0x82 thrsleep syz-fuzzer 31919 492609 4350 0 3 0x4000082 nanosleep syz-fuzzer 31919 485685 4350 0 3 0x4000082 thrsleep syz-fuzzer 31919 207818 4350 0 3 0x4000082 thrsleep syz-fuzzer 31919 49130 4350 0 3 0x4000082 thrsleep syz-fuzzer 31919 67811 4350 0 3 0x4000082 kqread syz-fuzzer 31919 198566 4350 0 3 0x4000082 thrsleep syz-fuzzer 31919 77692 4350 0 3 0x4000082 thrsleep syz-fuzzer 31919 42938 4350 0 3 0x4000082 thrsleep syz-fuzzer 31919 329808 4350 0 3 0x4000082 thrsleep syz-fuzzer 4350 64237 44183 0 3 0x10008a pause ksh 44183 31270 22142 0 3 0x92 select sshd 26934 501399 1 0 3 0x100083 ttyin getty 22142 6615 1 0 3 0x80 select sshd 91928 281404 66482 73 7 0x100090 syslogd 66482 356999 1 0 3 0x100082 netio syslogd 37229 253322 1 77 3 0x100090 poll dhclient 48816 89738 1 0 3 0x80 poll dhclient 82449 453870 0 0 3 0x14200 pgzero zerothread 64767 203378 0 0 3 0x14200 aiodoned aiodoned 73017 125028 0 0 3 0x14200 syncer update 8182 194953 0 0 3 0x14200 cleaner cleaner 76099 384736 0 0 3 0x14200 reaper reaper 87195 118574 0 0 3 0x14200 pgdaemon pagedaemon 49814 47250 0 0 3 0x14200 bored crynlk 3427 319868 0 0 3 0x14200 bored crypto 83117 278673 0 0 3 0x40014200 acpi0 acpi0 71215 243098 0 0 3 0x40014200 idle1 54906 401829 0 0 3 0x14200 bored softnet 34096 180178 0 0 3 0x14200 bored systqmp 38164 234191 0 0 3 0x14200 bored systq 85690 391942 0 0 3 0x40014200 bored softclock 36783 266248 0 0 3 0x40014200 idle0 1 521778 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{0}> show all locks Process 33189 (syz-executor.1) thread 0xffff800020b424c8 (28374) exclusive rwlock wsmuxlk r = 0 (0xffff800000026dd0) locked @ /syzkaller/managers/multicore/kernel/sys/dev/wscons/wsmux.c:626 #0 witness_lock+0x58a sys/kern/subr_witness.c:1205 #1 wsmux_attach_sc+0x48 sys/dev/wscons/wsmux.c:632 #2 VOP_IOCTL+0x9a sys/kern/vfs_vops.c:290 #3 vn_ioctl+0xc9 sys/kern/vfs_vnops.c:512 #4 sys_ioctl+0x646 #5 syscall+0x5ac mi_syscall sys/sys/syscall_mi.h:99 [inline] #5 syscall+0x5ac sys/arch/amd64/amd64/trap.c:574 #6 Xsyscall+0x128 exclusive kernel_lock &kernel_lock r = 0 (0xffffffff8235c720) locked @ /syzkaller/managers/multicore/kernel/sys/sys/syscall_mi.h:90 #0 witness_lock+0x58a sys/kern/subr_witness.c:1205 #1 syscall+0x47f mi_syscall sys/sys/syscall_mi.h:91 [inline] #1 syscall+0x47f sys/arch/amd64/amd64/trap.c:574 #2 Xsyscall+0x128 ddb{0}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim Kern Lim devbuf 9482 6347K 6352K 78643K 10782 0 0 pcb 23 9K 10K 78643K 288 0 0 rtable 100 3K 4K 78643K 270 0 0 ifaddr 43 11K 12K 78643K 101 0 0 counters 39 33K 33K 78643K 39 0 0 ioctlops 0 0K 2K 78643K 15 0 0 iov 0 0K 24K 78643K 59 0 0 mount 1 1K 1K 78643K 1 0 0 vnodes 1207 76K 76K 78643K 1702 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 25 0 0 VM map 2 1K 1K 78643K 2 0 0 sem 11 1K 1K 78643K 12 0 0 dirhash 12 2K 2K 78643K 12 0 0 ACPI 1792 194K 288K 78643K 12592 0 0 file desc 6 17K 25K 78643K 881 0 0 sigio 1 0K 0K 78643K 18 0 0 proc 42 38K 70K 78643K 359 0 0 subproc 64 65538K 67586K 78643K 73 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 68 0 0 in_multi 33 2K 2K 78643K 45 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 72 318K 318K 78643K 72 0 0 exec 0 0K 1K 78643K 197 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 20K 21K 78643K 3068 0 0 UVM aobj 27 2K 2K 78643K 27 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 16 0 0 NDP 7 0K 0K 78643K 27 0 0 temp 94 2352K 2426K 78643K 4897 0 0 kqueue 0 0K 0K 78643K 8 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 4 0 0 1 0 1 1 0 8 0 inpcbpl 280 345 0 338 1 0 1 1 0 8 0 plimitpl 152 35 0 28 1 0 1 1 0 8 0 plcache 128 20 0 0 1 0 1 1 0 8 0 rtentry 112 41 0 1 2 0 2 2 0 8 0 syncache 264 4 0 4 1 1 0 1 0 8 0 tcpcb 544 110 0 106 1 0 1 1 0 8 0 nd6 48 4 0 0 1 0 1 1 0 8 0 ppxss 1128 12 0 12 2 1 1 1 0 8 1 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 186 0 0 12 0 12 12 0 8 0 art_table 32 187 0 0 2 0 2 2 0 8 0 art_node 16 40 0 6 1 0 1 1 0 8 0 semapl 112 10 0 1 1 0 1 1 0 8 0 shmpl 112 25 0 0 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino1pl 128 3064 0 1641 47 1 46 47 0 8 0 ffsino 272 3064 0 1641 96 0 96 96 0 8 0 nchpl 144 4397 0 2773 61 0 61 61 0 8 0 uvmvnodes 72 3190 0 0 58 0 58 58 0 8 0 vnodes 200 3190 0 0 168 0 168 168 0 8 0 namei 1024 11056 0 11056 2 1 1 1 0 8 1 percpumem 16 30 0 0 1 0 1 1 0 8 0 scsiplug 64 4 0 4 1 1 0 1 0 8 0 scxspl 192 15907 0 15907 8 7 1 6 0 8 1 sigapl 432 1049 0 1035 2 0 2 2 0 8 0 futexpl 56 6100 0 6099 1 0 1 1 0 8 0 knotepl 112 185 0 158 2 1 1 2 0 8 0 kqueuepl 104 175 0 173 1 0 1 1 0 8 0 pipepl 112 230 0 211 2 1 1 1 0 8 0 fdescpl 488 1050 0 1035 3 1 2 3 0 8 0 filepl 152 4412 0 4316 8 4 4 5 0 8 0 lockfpl 104 285 0 284 5 4 1 1 0 8 0 lockfspl 32 354 0 353 5 4 1 1 0 8 0 sessionpl 112 17 0 7 1 0 1 1 0 8 0 pgrppl 48 17 0 7 1 0 1 1 0 8 0 ucredpl 96 1312 0 1305 1 0 1 1 0 8 0 zombiepl 144 1035 0 1035 2 1 1 1 0 8 1 processpl 840 1065 0 1035 4 0 4 4 0 8 0 procpl 600 2384 0 2342 4 0 4 4 0 8 0 sosppl 128 35 0 35 3 2 1 1 0 8 1 sockpl 384 577 0 560 6 3 3 3 0 8 1 mcl64k 65536 3 0 0 1 0 1 1 0 8 0 mcl9k 9216 3 0 0 1 0 1 1 0 8 0 mcl8k 8192 5 0 0 1 0 1 1 0 8 0 mcl4k 4096 6 0 0 1 0 1 1 0 8 0 mcl2k2 2112 5 0 0 1 0 1 1 0 8 0 mcl2k 2048 136 0 0 14 0 14 14 0 8 1 mtagpl 80 1 0 0 1 0 1 1 0 8 0 mbufpl 256 211 0 0 10 0 10 10 0 8 0 bufpl 256 9122 0 2150 436 0 436 436 0 8 0 anonpl 16 157489 0 154489 51 26 25 45 0 125 10 amapchunkpl 152 4722 0 4635 8 4 4 5 0 158 0 amappl16 192 8455 0 8336 41 30 11 30 0 8 4 amappl15 184 1 0 0 1 0 1 1 0 8 0 amappl14 176 441 0 438 2 1 1 1 0 8 0 amappl13 168 27 0 23 1 0 1 1 0 8 0 amappl12 160 438 0 434 2 1 1 1 0 8 0 amappl11 152 182 0 172 1 0 1 1 0 8 0 amappl10 144 52 0 52 2 2 0 1 0 8 0 amappl9 136 353 0 349 1 0 1 1 0 8 0 amappl8 128 563 0 540 1 0 1 1 0 8 0 amappl7 120 38 0 32 1 0 1 1 0 8 0 amappl6 112 502 0 492 1 0 1 1 0 8 0 amappl5 104 126 0 116 1 0 1 1 0 8 0 amappl4 96 267 0 248 1 0 1 1 0 8 0 amappl3 88 137 0 129 1 0 1 1 0 8 0 amappl2 80 9294 0 9231 2 0 2 2 0 8 0 amappl1 72 28132 0 27698 24 14 10 19 0 8 0 amappl 72 2633 0 2598 1 0 1 1 0 75 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 26 0 0 1 0 1 1 0 8 0 uaddrrnd 24 1050 0 1035 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 1050 0 1035 1 0 1 1 0 8 0 vmmpekpl 168 10412 0 10389 2 0 2 2 0 8 0 vmmpepl 168 116040 0 114890 106 50 56 72 0 357 5 vmsppl 360 1049 0 1035 2 0 2 2 0 8 0 pdppl 4096 2107 0 2070 6 1 5 6 0 8 0 pvpl 32 399975 0 393949 166 73 93 118 0 265 42 pmappl 224 1049 0 1035 1 0 1 1 0 8 0 extentpl 40 39 0 25 1 0 1 1 0 8 0 phpool 112 586 0 4 17 0 17 17 0 8 0