witness: acquiring duplicate lock of same type: "&sc->sc_lock" 1st wsmuxlk @ /syzkaller/managers/multicore/kernel/sys/dev/wscons/wsmux.c:242 2nd wsmuxlk @ /syzkaller/managers/multicore/kernel/sys/dev/wscons/wsmux.c:242 Starting stack trace... witness_checkorder(ffff800000026fd0,1,ffffffff81f354ca,f2,0) at witness_checkorder+0xe14 witness_debugger sys/kern/subr_witness.c:2650 [inline] witness_checkorder(ffff800000026fd0,1,ffffffff81f354ca,f2,0) at witness_checkorder+0xe14 sys/kern/subr_witness.c:926 _rw_enter_read(ffff800000026fc0,ffffffff81f354ca,f2) at _rw_enter_read+0x80 sys/kern/kern_rwlock.c:102 wsmux_mux_open(ffff800000026f00,ffff800000026d50) at wsmux_mux_open+0x82 wsmux_do_open sys/dev/wscons/wsmux.c:243 [inline] wsmux_mux_open(ffff800000026f00,ffff800000026d50) at wsmux_mux_open+0x82 sys/dev/wscons/wsmux.c:225 wsmuxopen(4500,3,2000,ffff800020b43c38) at wsmuxopen+0x179 wsmux_do_open sys/dev/wscons/wsmux.c:255 [inline] wsmuxopen(4500,3,2000,ffff800020b43c38) at wsmuxopen+0x179 sys/dev/wscons/wsmux.c:201 spec_open(ffff800020bef8c0) at spec_open+0x217 sys/kern/spec_vnops.c:158 VOP_OPEN(fffffd80742a3dd0,3,fffffd807f7c7b40,ffff800020b43c38) at VOP_OPEN+0x76 sys/kern/vfs_vops.c:153 vn_open(ffff800020befab0,3,0) at vn_open+0x4c6 sys/kern/vfs_vnops.c:174 doopenat(ffff800020b43c38,ffffff9c,20000040,2,0,ffff800020befcf0) at doopenat+0x2be sys/kern/vfs_syscalls.c:1045 syscall(ffff800020befda0) at syscall+0x5ac mi_syscall sys/sys/syscall_mi.h:99 [inline] syscall(ffff800020befda0) at syscall+0x5ac sys/arch/amd64/amd64/trap.c:574 Xsyscall(6,0,ffffffffffffffb1,0,4,86d53579010) at Xsyscall+0x128 end of kernel end trace frame: 0x86f732af190, count: 247 End of stack trace. 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:399 witness_checkorder(ffff800000026fd0,1,ffffffff81f354ca,f2,0) at witness_checkorder+0xe19 witness_debugger sys/kern/subr_witness.c:2650 [inline] witness_checkorder(ffff800000026fd0,1,ffffffff81f354ca,f2,0) at witness_checkorder+0xe19 sys/kern/subr_witness.c:926 _rw_enter_read(ffff800000026fc0,ffffffff81f354ca,f2) at _rw_enter_read+0x80 sys/kern/kern_rwlock.c:102 wsmux_mux_open(ffff800000026f00,ffff800000026d50) at wsmux_mux_open+0x82 wsmux_do_open sys/dev/wscons/wsmux.c:243 [inline] wsmux_mux_open(ffff800000026f00,ffff800000026d50) at wsmux_mux_open+0x82 sys/dev/wscons/wsmux.c:225 wsmuxopen(4500,3,2000,ffff800020b43c38) at wsmuxopen+0x179 wsmux_do_open sys/dev/wscons/wsmux.c:255 [inline] wsmuxopen(4500,3,2000,ffff800020b43c38) at wsmuxopen+0x179 sys/dev/wscons/wsmux.c:201 spec_open(ffff800020bef8c0) at spec_open+0x217 sys/kern/spec_vnops.c:158 VOP_OPEN(fffffd80742a3dd0,3,fffffd807f7c7b40,ffff800020b43c38) at VOP_OPEN+0x76 sys/kern/vfs_vops.c:153 vn_open(ffff800020befab0,3,0) at vn_open+0x4c6 sys/kern/vfs_vnops.c:174 doopenat(ffff800020b43c38,ffffff9c,20000040,2,0,ffff800020befcf0) at doopenat+0x2be sys/kern/vfs_syscalls.c:1045 syscall(ffff800020befda0) at syscall+0x5ac mi_syscall sys/sys/syscall_mi.h:99 [inline] syscall(ffff800020befda0) at syscall+0x5ac sys/arch/amd64/amd64/trap.c:574 Xsyscall(6,0,ffffffffffffffb1,0,4,86d53579010) at Xsyscall+0x128 end of kernel end trace frame: 0x86f732af190, count: -11 ddb{1}> show registers rdi 0 rsi 0x3ffff acpi_pdirpa+0x2be67 rbp 0xffff800020bef660 rbx 0x3 rdx 0x40000 acpi_pdirpa+0x2be68 rcx 0xffff800002b49000 rax 0xffff800001b47a40 r8 0xffffffff81316553 kprintf+0x183 r9 0x1 r10 0x25 r11 0xa5a1775e41c3c81b 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 0xffff800020bef650 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{1}> show proc PROC (syz-executor.1) pid=83506 stat=onproc flags process=0 proc=4000000 pri=61, usrpri=61, nice=20 forw=0xffffffffffffffff, list=0xffff800020b42e28,0xffffffff82334d38 process=0xffff800020b45708 user=0xffff800020bea000, vmspace=0xfffffd807f00d708 estcpu=22, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 98850 363204 25212 0 7 0 syz-executor.1 *98850 83506 25212 0 7 0x4000000 syz-executor.1 17924 261446 1 0 3 0x100083 ttyin getty 5800 338168 0 0 3 0x14200 bored sosplice 13980 183853 4122 0 3 0x82 nanosleep syz-executor.0 25212 244722 4122 0 3 0x82 nanosleep syz-executor.1 4122 498517 12706 0 3 0x82 thrsleep syz-fuzzer 4122 66876 12706 0 3 0x4000082 thrsleep syz-fuzzer 4122 461260 12706 0 3 0x4000082 thrsleep syz-fuzzer 4122 229245 12706 0 3 0x4000082 thrsleep syz-fuzzer 4122 90807 12706 0 3 0x4000082 thrsleep syz-fuzzer 4122 310138 12706 0 3 0x4000082 thrsleep syz-fuzzer 4122 282979 12706 0 3 0x4000082 thrsleep syz-fuzzer 4122 173386 12706 0 3 0x4000082 kqread syz-fuzzer 4122 96280 12706 0 3 0x4000082 thrsleep syz-fuzzer 4122 411559 12706 0 3 0x4000082 thrsleep syz-fuzzer 12706 416764 51464 0 3 0x10008a pause ksh 51464 254412 47263 0 3 0x92 select sshd 47263 423816 1 0 3 0x80 select sshd 42689 67585 93456 73 2 0x100090 syslogd 93456 508207 1 0 3 0x100082 netio syslogd 53689 121654 1 77 3 0x100090 poll dhclient 9816 192283 1 0 3 0x80 poll dhclient 52219 108021 0 0 3 0x14200 pgzero zerothread 77005 477988 0 0 3 0x14200 aiodoned aiodoned 47102 56025 0 0 3 0x14200 syncer update 29474 333110 0 0 3 0x14200 cleaner cleaner 34332 513129 0 0 3 0x14200 reaper reaper 26236 946 0 0 3 0x14200 pgdaemon pagedaemon 1170 478095 0 0 3 0x14200 bored crynlk 91876 132257 0 0 3 0x14200 bored crypto 678 187402 0 0 3 0x40014200 acpi0 acpi0 78310 366866 0 0 3 0x40014200 idle1 34634 512960 0 0 3 0x14200 bored softnet 29269 514251 0 0 3 0x14200 bored systqmp 974 436019 0 0 3 0x14200 bored systq 59592 283980 0 0 3 0x40014200 bored softclock 1514 521561 0 0 3 0x40014200 idle0 1 293578 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{1}> show all locks Process 98850 (syz-executor.1) thread 0xffff800020b43c38 (83506) shared rwlock wsmuxlk r = 0 (0xffff800000026dd0) locked @ /syzkaller/managers/multicore/kernel/sys/dev/wscons/wsmux.c:242 #0 witness_lock+0x58a sys/kern/subr_witness.c:1205 #1 wsmuxopen+0xf3 wsmux_do_open sys/dev/wscons/wsmux.c:243 [inline] #1 wsmuxopen+0xf3 sys/dev/wscons/wsmux.c:201 #2 spec_open+0x217 sys/kern/spec_vnops.c:158 #3 VOP_OPEN+0x76 sys/kern/vfs_vops.c:153 #4 vn_open+0x4c6 sys/kern/vfs_vnops.c:174 #5 doopenat+0x2be sys/kern/vfs_syscalls.c:1045 #6 syscall+0x5ac mi_syscall sys/sys/syscall_mi.h:99 [inline] #6 syscall+0x5ac sys/arch/amd64/amd64/trap.c:574 #7 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{1}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim Kern Lim devbuf 9522 6368K 6377K 78643K 11257 0 0 pcb 23 9K 11K 78643K 999 0 0 rtable 100 3K 4K 78643K 631 0 0 ifaddr 56 14K 15K 78643K 288 0 0 counters 39 33K 33K 78643K 39 0 0 ioctlops 0 0K 2K 78643K 43 0 0 iov 0 0K 28K 78643K 216 0 0 mount 1 1K 1K 78643K 1 0 0 vnodes 1199 75K 76K 78643K 2383 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 35 0 0 VM map 2 1K 1K 78643K 2 0 0 sem 12 0K 0K 78643K 217 0 0 dirhash 12 2K 2K 78643K 12 0 0 ACPI 1792 194K 288K 78643K 12592 0 0 file desc 5 13K 21K 78643K 1877 0 0 sigio 0 0K 0K 78643K 30 0 0 proc 43 38K 58K 78643K 623 0 0 subproc 64 65538K 67586K 78643K 185 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 253 0 0 in_multi 33 2K 2K 78643K 148 0 0 ether_multi 1 0K 0K 78643K 15 0 0 ISOFS mount 1 32K 32K 78643K 1 0 0 MSDOSFS mount 1 16K 16K 78643K 1 0 0 ttys 102 450K 450K 78643K 102 0 0 exec 0 0K 1K 78643K 327 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 100 21K 30K 78643K 6905 0 0 UVM aobj 110 4K 4K 78643K 122 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 53 0 0 NDP 11 0K 0K 78643K 82 0 0 temp 163 2367K 2435K 78643K 8101 0 0 kqueue 0 0K 0K 78643K 8 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 7 0 3 1 0 1 1 0 8 0 inpcbpl 280 915 0 908 1 0 1 1 0 8 0 plimitpl 152 45 0 38 1 0 1 1 0 8 0 plcache 128 20 0 0 1 0 1 1 0 8 0 rtentry 112 68 0 28 2 0 2 2 0 8 0 syncache 264 4 0 4 1 1 0 1 0 8 0 tcpcb 544 306 0 302 1 0 1 1 0 8 0 nd6 48 10 0 6 1 0 1 1 0 8 0 ppxss 1128 45 0 45 13 12 1 1 0 8 1 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 308 0 123 12 0 12 12 0 8 0 art_table 32 309 0 123 2 0 2 2 0 8 0 art_node 16 67 0 33 1 0 1 1 0 8 0 sysvmsgpl 40 16 0 9 1 0 1 1 0 8 0 semupl 112 1 0 1 1 1 0 1 0 8 0 semapl 112 213 0 203 1 0 1 1 0 8 0 shmpl 112 120 0 12 4 0 4 4 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino1pl 128 5065 0 3641 47 0 47 47 0 8 1 ffsino 272 5065 0 3641 96 0 96 96 0 8 0 nchpl 144 8038 0 6435 61 0 61 61 0 8 0 uvmvnodes 72 5357 0 0 98 0 98 98 0 8 0 vnodes 200 5357 0 0 282 0 282 282 0 8 0 namei 1024 23783 0 23783 4 3 1 1 0 8 1 percpumem 16 30 0 0 1 0 1 1 0 8 0 scsiplug 64 7 0 7 6 5 1 1 0 8 1 scxspl 192 23375 0 23375 16 15 1 6 0 8 1 sigapl 432 2040 0 2027 2 0 2 2 0 8 0 futexpl 56 24793 0 24793 2 1 1 1 0 8 1 knotepl 112 485 0 458 3 2 1 2 0 8 0 kqueuepl 104 509 0 507 1 0 1 1 0 8 0 pipepl 112 1350 0 1331 6 5 1 2 0 8 0 fdescpl 488 2041 0 2027 3 1 2 3 0 8 0 filepl 152 12441 0 12346 16 11 5 6 0 8 1 lockfpl 104 637 0 637 6 5 1 1 0 8 1 lockfspl 32 922 0 922 5 4 1 1 0 8 1 sessionpl 112 24 0 14 1 0 1 1 0 8 0 pgrppl 48 42 0 32 1 0 1 1 0 8 0 ucredpl 96 3291 0 3284 1 0 1 1 0 8 0 zombiepl 144 2027 0 2026 2 1 1 1 0 8 0 processpl 840 2056 0 2026 4 0 4 4 0 8 0 procpl 600 6150 0 6110 4 0 4 4 0 8 0 srpgc 64 18 0 18 1 1 0 1 0 8 0 sosppl 128 49 0 49 12 11 1 1 0 8 1 sockpl 384 1787 0 1770 15 12 3 4 0 8 1 mcl64k 65536 232 0 0 29 23 6 29 0 8 1 mcl16k 16384 3 0 0 1 0 1 1 0 8 0 mcl12k 12288 15 0 0 2 0 2 2 0 8 0 mcl9k 9216 13 0 0 1 0 1 1 0 8 0 mcl8k 8192 6 0 0 1 0 1 1 0 8 0 mcl4k 4096 15 0 0 2 0 2 2 0 8 0 mcl2k2 2112 5 0 0 1 0 1 1 0 8 0 mcl2k 2048 126 0 0 13 1 12 13 0 8 0 mtagpl 80 1 0 0 1 0 1 1 0 8 0 mbufpl 256 573 0 0 27 0 27 27 0 8 0 bufpl 256 9296 0 2324 437 1 436 437 0 8 0 anonpl 16 215907 0 207671 125 75 50 50 0 125 15 amapchunkpl 152 12655 0 12566 32 27 5 9 0 158 0 amappl16 192 10646 0 10210 86 56 30 34 0 8 8 amappl15 184 3 0 2 1 0 1 1 0 8 0 amappl14 176 901 0 899 2 1 1 1 0 8 0 amappl13 168 947 0 942 1 0 1 1 0 8 0 amappl12 160 19 0 15 2 1 1 1 0 8 0 amappl11 152 190 0 181 1 0 1 1 0 8 0 amappl10 144 112 0 110 2 1 1 1 0 8 0 amappl9 136 287 0 283 1 0 1 1 0 8 0 amappl8 128 187 0 154 3 1 2 2 0 8 0 amappl7 120 958 0 950 1 0 1 1 0 8 0 amappl6 112 947 0 941 1 0 1 1 0 8 0 amappl5 104 299 0 287 1 0 1 1 0 8 0 amappl4 96 303 0 280 2 1 1 2 0 8 0 amappl3 88 197 0 192 1 0 1 1 0 8 0 amappl2 80 19062 0 19009 2 0 2 2 0 8 0 amappl1 72 51914 0 51491 24 14 10 19 0 8 0 amappl 72 6414 0 6380 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 64 121 0 12 2 0 2 2 0 8 0 uaddrrnd 24 2041 0 2027 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 2041 0 2027 1 0 1 1 0 8 0 vmmpekpl 168 19687 0 19663 2 0 2 2 0 8 0 vmmpepl 168 222076 0 220680 131 55 76 76 0 357 11 vmsppl 360 2040 0 2027 2 0 2 2 0 8 0 pdppl 4096 4089 0 4054 5 0 5 5 0 8 0 pvpl 32 586955 0 575730 272 143 129 129 0 265 37 pmappl 224 2040 0 2027 1 0 1 1 0 8 0 extentpl 40 39 0 25 1 0 1 1 0 8 0 phpool 112 634 0 30 18 0 18 18 0 8 0