login: witness: panic: kernel diagnostic assertion "_kernel_lock_held()" failed: file "/syzkaller/managers/setuid/kernel/sys/kern/kern_event.c", line 1076 Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *311700 6806 32767 0x10 0x4000000 1 syz-executor4079 524263 34869 32767 0x10 0x480 0 syz-executor4079 db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic() at panic+0x15c sys/kern/subr_prf.c:208 __assert(ffffffff81f8c2bf,ffffffff81f90d96,434,ffffffff81f96de6) at __assert+0x2e sys/kern/subr_prf.c:155 knote_enqueue(fffffd806ec57d20) at knote_enqueue+0x216 sys/kern/kern_event.c:1076 knote(ffffffff8234b168,1000000) at knote+0xbd sys/kern/kern_event.c:957 selwakeup(ffffffff8234b168) at selwakeup+0x3b sys/kern/sys_generic.c:795 logwakeup() at logwakeup+0x3b sys/kern/subr_log.c:310 printf(ffffffff81f6acf3) at printf+0x9f sys/kern/subr_prf.c:519 witness_warn(2,0,ffffffff81f92281) at witness_warn+0x211 sys/kern/subr_witness.c:1416 userret(ffff800020b14008) at userret+0x32a sys/kern/kern_sig.c:1902 syscall(ffff800020be5c90) at syscall+0x614 mi_syscall_return sys/sys/syscall_mi.h:122 [inline] syscall(ffff800020be5c90) at syscall+0x614 sys/arch/amd64/amd64/trap.c:596 Xsyscall(6,5,e9eef3fb288,0,e9eef3fb268,e9eef3fb260) at Xsyscall+0x128 end of kernel end trace frame: 0xea1384dfa10, count: 3 https://www.openbsd.org/ddb.html describes the minimum info required in bug reports. Insufficient info makes it difficult to find and fix bugs. ddb{1}> ddb{1}> set $lines = 0 ddb{1}> set $maxwidth = 0 ddb{1}> show panic kernel diagnostic assertion "_kernel_lock_held()" failed: file "/syzkaller/managers/setuid/kernel/sys/kern/kern_event.c", line 1076 ddb{1}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic() at panic+0x15c sys/kern/subr_prf.c:208 __assert(ffffffff81f8c2bf,ffffffff81f90d96,434,ffffffff81f96de6) at __assert+0x2e sys/kern/subr_prf.c:155 knote_enqueue(fffffd806ec57d20) at knote_enqueue+0x216 sys/kern/kern_event.c:1076 knote(ffffffff8234b168,1000000) at knote+0xbd sys/kern/kern_event.c:957 selwakeup(ffffffff8234b168) at selwakeup+0x3b sys/kern/sys_generic.c:795 logwakeup() at logwakeup+0x3b sys/kern/subr_log.c:310 printf(ffffffff81f6acf3) at printf+0x9f sys/kern/subr_prf.c:519 witness_warn(2,0,ffffffff81f92281) at witness_warn+0x211 sys/kern/subr_witness.c:1416 userret(ffff800020b14008) at userret+0x32a sys/kern/kern_sig.c:1902 syscall(ffff800020be5c90) at syscall+0x614 mi_syscall_return sys/sys/syscall_mi.h:122 [inline] syscall(ffff800020be5c90) at syscall+0x614 sys/arch/amd64/amd64/trap.c:596 Xsyscall(6,5,e9eef3fb288,0,e9eef3fb268,e9eef3fb260) at Xsyscall+0x128 end of kernel end trace frame: 0xea1384dfa10, count: -12 ddb{1}> show registers rdi 0 rsi 0x1 rbp 0xffff800020be5800 rbx 0xffff800020be58b0 rdx 0x8b rcx 0x2 rax 0x1 r8 0xffffffff81df1983 kprintf+0x173 r9 0x1 r10 0xbc7e49610bab61f9 r11 0xbffcad399a1fdb0c r12 0x3000000008 r13 0xffff800020be5810 r14 0x100 r15 0x1 rip 0xffffffff81c2c858 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800020be57f0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{1}> show proc PROC (syz-executor4079) pid=311700 stat=onproc flags process=10 proc=4000000 pri=32, usrpri=63, nice=20 forw=0xffffffffffffffff, list=0xffff800020b14710,0xffff800020b15530 process=0xffff800020b3a6a0 user=0xffff800020be0000, vmspace=0xfffffd807effd708 estcpu=13, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 65336 393080 34620 32767 2 0x10 syz-executor4079 65336 244198 34620 32767 3 0x4000090 fsleep syz-executor4079 65336 433116 34620 32767 2 0x4000090 syz-executor4079 6806 264436 34869 32767 2 0x10 syz-executor4079 * 6806 311700 34869 32767 7 0x4000010 syz-executor4079 6806 40847 34869 32767 3 0x4000090 fsleep syz-executor4079 6806 485940 34869 32767 2 0x4000010 syz-executor4079 34620 380345 35052 32767 3 0x90 nanosleep syz-executor4079 34869 524263 36380 32767 7 0x490 syz-executor4079 35052 160964 65466 0 3 0x80 wait syz-executor4079 36380 308764 65466 0 3 0x80 wait syz-executor4079 65466 317990 65088 0 3 0x82 nanosleep syz-executor4079 65088 178656 11103 0 3 0x10008a pause ksh 11103 290261 80348 0 3 0x92 select sshd 6558 333422 1 0 3 0x100083 ttyin getty 80348 143113 1 0 3 0x80 select sshd 18416 362853 99472 73 3 0x100090 kqread syslogd 99472 255932 1 0 3 0x100082 netio syslogd 69013 313742 1 77 3 0x100090 poll dhclient 69575 318374 1 0 3 0x80 poll dhclient 76534 345340 0 0 3 0x14200 pgzero zerothread 25686 141498 0 0 3 0x14200 aiodoned aiodoned 80179 122887 0 0 3 0x14200 syncer update 70940 339976 0 0 3 0x14200 cleaner cleaner 9758 337158 0 0 3 0x14200 reaper reaper 84386 82687 0 0 3 0x14200 pgdaemon pagedaemon 86482 47439 0 0 3 0x14200 bored crynlk 50168 363702 0 0 3 0x14200 bored crypto 49943 436723 0 0 3 0x40014200 acpi0 acpi0 18709 120089 0 0 3 0x40014200 idle1 93715 326062 0 0 3 0x14200 bored softnet 38828 227400 0 0 3 0x14200 bored systqmp 7275 8963 0 0 3 0x14200 bored systq 96276 381000 0 0 3 0x40014200 bored softclock 73351 309821 0 0 3 0x40014200 idle0 45081 444877 0 0 3 0x14200 bored smr 1 405788 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{1}> show all locks Process 6806 (syz-executor4079) thread 0xffff800020b14008 (311700) exclusive rrwlock inode r = 0 (0xfffffd806f7cfa30) #0 witness_lock+0x52e sys/kern/subr_witness.c:1161 #1 rw_enter+0x414 sys/kern/kern_rwlock.c:278 #2 rrw_enter+0x4f sys/kern/kern_rwlock.c:407 #3 VOP_LOCK+0x4b sys/kern/vfs_vops.c:602 #4 vn_write+0x169 vn_lock sys/kern/vfs_vnops.c:549 [inline] #4 vn_write+0x169 sys/kern/vfs_vnops.c:393 #5 dofilewritev+0x1a9 sys/kern/sys_generic.c:364 #6 sys_write+0x83 sys/kern/sys_generic.c:284 #7 syscall+0x552 mi_syscall sys/sys/syscall_mi.h:99 [inline] #7 syscall+0x552 sys/arch/amd64/amd64/trap.c:574 #8 Xsyscall+0x128 ddb{1}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim Kern Lim devbuf 9447 6316K 6316K 78643K 10534 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 1166 73K 73K 78643K 2078 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 1808 196K 290K 78643K 12628 0 0 file desc 3 4K 5K 78643K 1054 0 0 proc 41 38K 46K 78643K 208 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 48 212K 212K 78643K 48 0 0 exec 0 0K 1K 78643K 152 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 64 19K 19K 78643K 1994 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 2699K 2763K 78643K 2406 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 2 0 0 1 0 1 1 0 8 0 inpcbpl 280 22 0 16 1 0 1 1 0 8 0 plimitpl 152 15 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 2 2 0 1 0 8 0 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 2641 0 1272 45 0 45 45 0 8 0 ffsino 272 2641 0 1272 92 0 92 92 0 8 0 nchpl 144 3165 0 1637 57 0 57 57 0 8 0 uvmvnodes 72 2650 0 0 49 0 49 49 0 8 0 vnodes 200 2650 0 0 140 0 140 140 0 8 0 namei 1024 10294 0 10294 2 1 1 1 0 8 1 percpumem 16 30 0 0 1 0 1 1 0 8 0 scxspl 192 5202 0 5202 13 12 1 6 0 8 1 sigapl 432 531 0 515 2 0 2 2 0 8 0 futexpl 56 3093 0 3091 1 0 1 1 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 112 118 0 111 2 1 1 1 0 8 0 fdescpl 488 532 0 515 3 0 3 3 0 8 0 filepl 152 5376 0 5325 3 0 3 3 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 19 0 9 1 0 1 1 0 8 0 pgrppl 48 19 0 9 1 0 1 1 0 8 0 ucredpl 96 4262 0 4253 1 0 1 1 0 8 0 zombiepl 144 515 0 515 3 2 1 1 0 8 1 processpl 840 547 0 515 4 0 4 4 0 8 0 procpl 600 1521 0 1484 5 2 3 4 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 87 0 0 10 0 10 10 0 8 0 mtagpl 80 1 0 0 1 0 1 1 0 8 0 mbufpl 256 123 0 0 7 0 7 7 0 8 0 bufpl 256 2435 0 245 137 0 137 137 0 8 0 anonpl 16 39620 0 38347 7 1 6 6 0 125 0 amapchunkpl 152 2796 0 2745 3 0 3 3 0 158 0 amappl16 192 619 0 608 1 0 1 1 0 8 0 amappl14 176 14 0 13 3 2 1 1 0 8 0 amappl12 160 10 0 10 2 2 0 1 0 8 0 amappl11 152 44 0 30 1 0 1 1 0 8 0 amappl10 144 46 0 46 2 2 0 1 0 8 0 amappl9 136 413 0 407 1 0 1 1 0 8 0 amappl8 128 84 0 80 1 0 1 1 0 8 0 amappl7 120 15 0 14 1 0 1 1 0 8 0 amappl6 112 45 0 40 1 0 1 1 0 8 0 amappl5 104 116 0 107 1 0 1 1 0 8 0 amappl4 96 1088 0 1059 1 0 1 1 0 8 0 amappl3 88 107 0 101 1 0 1 1 0 8 0 amappl2 80 3730 0 3672 2 0 2 2 0 8 0 amappl1 72 24121 0 23642 14 4 10 14 0 8 0 amappl 72 1700 0 1668 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 24 532 0 515 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 532 0 515 1 0 1 1 0 8 0 vmmpekpl 168 8055 0 8034 2 0 2 2 0 8 0 vmmpepl 168 56587 0 55621 62 19 43 44 0 357 0 vmsppl 360 531 0 515 2 0 2 2 0 8 0 pdppl 4096 1072 0 1030 6 0 6 6 0 8 0 pvpl 32 120993 0 117875 33 7 26 26 0 265 0 pmappl 232 531 0 515 1 0 1 1 0 8 0 extentpl 40 39 0 25 1 0 1 1 0 8 0 phpool 112 268 0 3 8 0 8 8 0 8 0