login: 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(ffff800000026dd0,1,ffffffff81f354ca,f2,0) at witness_checkorder+0xe14 witness_debugger sys/kern/subr_witness.c:2650 [inline] witness_checkorder(ffff800000026dd0,1,ffffffff81f354ca,f2,0) at witness_checkorder+0xe14 sys/kern/subr_witness.c:926 _rw_enter_read(ffff800000026dc0,ffffffff81f354ca,f2) at _rw_enter_read+0x80 sys/kern/kern_rwlock.c:102 wsmux_mux_open(ffff800000026d00,ffff80000069ed50) at wsmux_mux_open+0x82 wsmux_do_open sys/dev/wscons/wsmux.c:243 [inline] wsmux_mux_open(ffff800000026d00,ffff80000069ed50) at wsmux_mux_open+0x82 sys/dev/wscons/wsmux.c:225 wsmux_attach_sc(ffff80000069ed00,ffff800000026d00) at wsmux_attach_sc+0x180 sys/dev/wscons/wsmux.c:667 VOP_IOCTL(fffffd806dc977d8,80085761,ffff800020baf4f0,f,fffffd807f7c7c60,ffff800020b95078) at VOP_IOCTL+0x9a sys/kern/vfs_vops.c:290 vn_ioctl(fffffd806fcae1c8,80085761,ffff800020baf4f0,ffff800020b95078) at vn_ioctl+0xc9 sys/kern/vfs_vnops.c:512 sys_ioctl(ffff800020b95078,ffff800020baf638,ffff800020baf620) at sys_ioctl+0x646 syscall(ffff800020baf6d0) at syscall+0x5ac mi_syscall sys/sys/syscall_mi.h:99 [inline] syscall(ffff800020baf6d0) at syscall+0x5ac sys/arch/amd64/amd64/trap.c:574 Xsyscall(6,0,7f7ffffcad68,0,1,7f7ffffcad78) at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffcad00, 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(ffff800000026dd0,1,ffffffff81f354ca,f2,0) at witness_checkorder+0xe19 witness_debugger sys/kern/subr_witness.c:2650 [inline] witness_checkorder(ffff800000026dd0,1,ffffffff81f354ca,f2,0) at witness_checkorder+0xe19 sys/kern/subr_witness.c:926 _rw_enter_read(ffff800000026dc0,ffffffff81f354ca,f2) at _rw_enter_read+0x80 sys/kern/kern_rwlock.c:102 wsmux_mux_open(ffff800000026d00,ffff80000069ed50) at wsmux_mux_open+0x82 wsmux_do_open sys/dev/wscons/wsmux.c:243 [inline] wsmux_mux_open(ffff800000026d00,ffff80000069ed50) at wsmux_mux_open+0x82 sys/dev/wscons/wsmux.c:225 wsmux_attach_sc(ffff80000069ed00,ffff800000026d00) at wsmux_attach_sc+0x180 sys/dev/wscons/wsmux.c:667 VOP_IOCTL(fffffd806dc977d8,80085761,ffff800020baf4f0,f,fffffd807f7c7c60,ffff800020b95078) at VOP_IOCTL+0x9a sys/kern/vfs_vops.c:290 vn_ioctl(fffffd806fcae1c8,80085761,ffff800020baf4f0,ffff800020b95078) at vn_ioctl+0xc9 sys/kern/vfs_vnops.c:512 sys_ioctl(ffff800020b95078,ffff800020baf638,ffff800020baf620) at sys_ioctl+0x646 syscall(ffff800020baf6d0) at syscall+0x5ac mi_syscall sys/sys/syscall_mi.h:99 [inline] syscall(ffff800020baf6d0) at syscall+0x5ac sys/arch/amd64/amd64/trap.c:574 Xsyscall(6,0,7f7ffffcad68,0,1,7f7ffffcad78) at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffcad00, count: -10 ddb{0}> show registers rdi 0 rsi 0 rbp 0xffff800020baf120 rbx 0x3 rdx 0xffffffff81f52f17 apollo_pio_rec+0xa34b rcx 0x201 rax 0x14 r8 0xffffffff81316553 kprintf+0x183 r9 0x1 r10 0x67371e6496edc06b r11 0x59e0b9fc10b215ae 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 0xffff800020baf110 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{0}> show proc PROC (syz-executor4885) pid=339125 stat=onproc flags process=2 proc=0 pri=51, usrpri=51, nice=20 forw=0xffffffffffffffff, list=0xffff800020b94010,0xffffffff82334d38 process=0xffff800020b7a360 user=0xffff800020baa000, vmspace=0xfffffd806e9739e0 estcpu=1, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND *92409 339125 41920 0 7 0x2 syz-executor4885 41920 152467 18834 0 3 0x10008a pause ksh 18834 213292 91967 0 3 0x92 select sshd 4663 522458 1 0 3 0x100083 ttyin getty 91967 384704 1 0 3 0x80 select sshd 54303 332731 44759 73 7 0x100090 syslogd 44759 183979 1 0 3 0x100082 netio syslogd 48617 151159 1 77 3 0x100090 poll dhclient 64938 261895 1 0 3 0x80 poll dhclient 11046 294389 0 0 3 0x14200 pgzero zerothread 47403 144960 0 0 3 0x14200 aiodoned aiodoned 22838 408602 0 0 3 0x14200 syncer update 29570 9065 0 0 3 0x14200 cleaner cleaner 23441 221776 0 0 3 0x14200 reaper reaper 74094 339835 0 0 3 0x14200 pgdaemon pagedaemon 7642 13249 0 0 3 0x14200 bored crynlk 69130 176507 0 0 3 0x14200 bored crypto 64478 508683 0 0 3 0x40014200 acpi0 acpi0 46057 51299 0 0 3 0x40014200 idle1 47849 449681 0 0 3 0x14200 bored softnet 46479 239090 0 0 3 0x14200 bored systqmp 49508 104188 0 0 3 0x14200 bored systq 61305 382881 0 0 3 0x40014200 bored softclock 7244 389438 0 0 3 0x40014200 idle0 1 371115 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{0}> show all locks Process 92409 (syz-executor4885) thread 0xffff800020b95078 (339125) exclusive rwlock wsmuxlk r = 0 (0xffff80000069edd0) 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 9444 6323K 6323K 78643K 10532 0 0 pcb 23 9K 9K 78643K 55 0 0 rtable 61 2K 2K 78643K 115 0 0 ifaddr 21 7K 7K 78643K 21 0 0 counters 39 33K 33K 78643K 39 0 0 ioctlops 0 0K 2K 78643K 13 0 0 mount 1 1K 1K 78643K 1 0 0 vnodes 1167 73K 73K 78643K 1172 0 0 UFS quota 1 32K 32K 78643K 1 0 0 UFS mount 5 36K 36K 78643K 5 0 0 shm 2 1K 1K 78643K 2 0 0 VM map 2 1K 1K 78643K 2 0 0 sem 2 0K 0K 78643K 2 0 0 dirhash 12 2K 2K 78643K 12 0 0 ACPI 1792 194K 288K 78643K 12592 0 0 file desc 1 0K 0K 78643K 1 0 0 proc 40 38K 46K 78643K 207 0 0 NFS srvsock 1 0K 0K 78643K 1 0 0 NFS daemon 1 16K 16K 78643K 1 0 0 in_multi 11 0K 0K 78643K 11 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 18 79K 79K 78643K 18 0 0 exec 0 0K 1K 78643K 150 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 47 2K 3K 78643K 651 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 NDP 3 0K 0K 78643K 3 0 0 temp 30 2347K 2411K 78643K 1695 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 2 0 0 1 0 1 1 0 8 0 inpcbpl 280 22 0 16 1 0 1 1 0 8 0 plimitpl 152 13 0 8 1 0 1 1 0 8 0 plcache 128 20 0 0 1 0 1 1 0 8 0 rtentry 112 23 0 1 1 0 1 1 0 8 0 syncache 264 5 0 5 1 0 1 1 0 8 1 tcpcb 544 8 0 5 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 96 0 0 6 0 6 6 0 8 0 art_table 32 97 0 0 1 0 1 1 0 8 0 art_node 16 22 0 2 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino1pl 128 1383 0 17 45 0 45 45 0 8 0 ffsino 272 1383 0 17 92 0 92 92 0 8 0 nchpl 144 1555 0 30 57 0 57 57 0 8 0 uvmvnodes 72 1392 0 0 26 0 26 26 0 8 0 vnodes 200 1392 0 0 74 0 74 74 0 8 0 namei 1024 3262 0 3262 2 1 1 1 0 8 1 percpumem 16 30 0 0 1 0 1 1 0 8 0 scxspl 192 2230 0 2230 2 1 1 2 0 8 1 sigapl 432 174 0 164 2 0 2 2 0 8 0 knotepl 112 5 0 0 1 0 1 1 0 8 0 kqueuepl 104 1 0 0 1 0 1 1 0 8 0 pipepl 112 114 0 107 2 1 1 1 0 8 0 fdescpl 488 175 0 164 2 0 2 2 0 8 0 filepl 152 808 0 765 2 0 2 2 0 8 0 lockfpl 104 6 0 6 1 1 0 1 0 8 0 lockfspl 32 3 0 3 1 1 0 1 0 8 0 sessionpl 112 17 0 9 1 0 1 1 0 8 0 pgrppl 48 17 0 9 1 0 1 1 0 8 0 ucredpl 96 47 0 40 1 0 1 1 0 8 0 zombiepl 144 164 0 164 2 1 1 1 0 8 1 processpl 840 189 0 164 4 0 4 4 0 8 0 procpl 600 189 0 164 3 0 3 3 0 8 0 sockpl 384 64 0 48 2 0 2 2 0 8 0 mcl4k 4096 2 0 0 1 0 1 1 0 8 0 mcl2k 2048 56 0 0 7 0 7 7 0 8 0 mtagpl 80 1 0 0 1 0 1 1 0 8 0 mbufpl 256 75 0 0 5 0 5 5 0 8 0 bufpl 256 1998 0 254 109 0 109 109 0 8 0 anonpl 16 16670 0 15588 6 1 5 6 0 125 0 amapchunkpl 152 487 0 452 2 0 2 2 0 158 0 amappl16 192 72 0 67 1 0 1 1 0 8 0 amappl15 184 1 0 0 1 0 1 1 0 8 0 amappl14 176 1 0 1 1 1 0 1 0 8 0 amappl13 168 16 0 13 1 0 1 1 0 8 0 amappl12 160 6 0 6 1 1 0 1 0 8 0 amappl11 152 174 0 165 1 0 1 1 0 8 0 amappl10 144 44 0 43 1 0 1 1 0 8 0 amappl9 136 205 0 204 1 0 1 1 0 8 0 amappl8 128 106 0 100 1 0 1 1 0 8 0 amappl7 120 29 0 25 1 0 1 1 0 8 0 amappl6 112 41 0 37 1 0 1 1 0 8 0 amappl5 104 139 0 128 1 0 1 1 0 8 0 amappl4 96 258 0 239 1 0 1 1 0 8 0 amappl3 88 112 0 107 1 0 1 1 0 8 0 amappl2 80 564 0 529 1 0 1 1 0 8 0 amappl1 72 11499 0 11118 14 4 10 14 0 8 0 amappl 72 365 0 346 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 1 0 0 1 0 1 1 0 8 0 uaddrrnd 24 175 0 164 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 175 0 164 1 0 1 1 0 8 0 vmmpekpl 168 5133 0 5113 1 0 1 1 0 8 0 vmmpepl 168 23435 0 22751 43 9 34 43 0 357 3 vmsppl 360 174 0 164 2 0 2 2 0 8 0 pdppl 4096 357 0 328 5 0 5 5 0 8 0 pvpl 32 68960 0 66254 29 3 26 26 0 265 1 pmappl 224 174 0 164 1 0 1 1 0 8 0 extentpl 40 39 0 25 1 0 1 1 0 8 0 phpool 112 234 0 3 7 0 7 7 0 8 0 ddb{0}>