witness: panic: kernel diagnostic assertion "_kernel_lock_held()" failed: file "/syzkaller/managers/multicore/kernel/sys/kern/kern_event.c", line 1076 Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND 484798 15229 0 0 0 1 syz-executor.0 *147795 15229 0 0 0x4000000 0 syz-executor.0 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(ffffffff81f8e31d,ffffffff81f86db9,434,ffffffff81f98402) at __assert+0x2e sys/kern/subr_prf.c:155 knote_enqueue(fffffd806ec7cd90) at knote_enqueue+0x216 sys/kern/kern_event.c:1076 knote(ffffffff82338c38,1000000) at knote+0xbd sys/kern/kern_event.c:957 selwakeup(ffffffff82338c38) at selwakeup+0x3b sys/kern/sys_generic.c:795 logwakeup() at logwakeup+0x3b sys/kern/subr_log.c:310 printf(ffffffff81f6bd50) at printf+0x9f sys/kern/subr_prf.c:519 witness_warn(2,0,ffffffff81f94722) at witness_warn+0x211 sys/kern/subr_witness.c:1416 userret(ffff800020b38978) at userret+0x32a sys/kern/kern_sig.c:1902 syscall(ffff800020c69630) at syscall+0x614 mi_syscall_return sys/sys/syscall_mi.h:122 [inline] syscall(ffff800020c69630) at syscall+0x614 sys/arch/amd64/amd64/trap.c:596 Xsyscall(6,0,fffffffffffffef6,0,1,e0acde13330) at Xsyscall+0x128 end of kernel end trace frame: 0x78, 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{0}> ddb{0}> set $lines = 0 ddb{0}> set $maxwidth = 0 ddb{0}> show panic kernel diagnostic assertion "_kernel_lock_held()" failed: file "/syzkaller/managers/multicore/kernel/sys/kern/kern_event.c", line 1076 ddb{0}> 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(ffffffff81f8e31d,ffffffff81f86db9,434,ffffffff81f98402) at __assert+0x2e sys/kern/subr_prf.c:155 knote_enqueue(fffffd806ec7cd90) at knote_enqueue+0x216 sys/kern/kern_event.c:1076 knote(ffffffff82338c38,1000000) at knote+0xbd sys/kern/kern_event.c:957 selwakeup(ffffffff82338c38) at selwakeup+0x3b sys/kern/sys_generic.c:795 logwakeup() at logwakeup+0x3b sys/kern/subr_log.c:310 printf(ffffffff81f6bd50) at printf+0x9f sys/kern/subr_prf.c:519 witness_warn(2,0,ffffffff81f94722) at witness_warn+0x211 sys/kern/subr_witness.c:1416 userret(ffff800020b38978) at userret+0x32a sys/kern/kern_sig.c:1902 syscall(ffff800020c69630) at syscall+0x614 mi_syscall_return sys/sys/syscall_mi.h:122 [inline] syscall(ffff800020c69630) at syscall+0x614 sys/arch/amd64/amd64/trap.c:596 Xsyscall(6,0,fffffffffffffef6,0,1,e0acde13330) at Xsyscall+0x128 end of kernel end trace frame: 0x78, count: -12 ddb{0}> show registers rdi 0xffffffff814647a7 db_enter+0x17 rsi 0x3711 __ALIGN_SIZE+0x2711 rbp 0xffff800020c691a0 rbx 0xffff800020c69250 rdx 0x3712 __ALIGN_SIZE+0x2712 rcx 0xffff8000011ba000 rax 0xffff8000011ba000 r8 0xffffffff8140baf3 kprintf+0x173 r9 0x1 r10 0x25 r11 0xc264c886134afcfa r12 0x3000000008 r13 0xffff800020c691b0 r14 0x100 r15 0x1 rip 0xffffffff814647a8 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800020c69190 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{0}> show proc PROC (syz-executor.0) pid=147795 stat=onproc flags process=0 proc=4000000 pri=32, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffff800020b39788,0xffffffff82355ec8 process=0xffff800020b8c9f0 user=0xffff800020c64000, vmspace=0xfffffd807effeb40 estcpu=36, cpticks=1, pctcpu=0.0 user=0, sys=1, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 15229 484798 22859 0 7 0 syz-executor.0 15229 11722 22859 0 3 0x4000080 lockf syz-executor.0 15229 82896 22859 0 3 0x4000080 fsleep syz-executor.0 15229 322530 22859 0 2 0x4000000 syz-executor.0 15229 305039 22859 0 3 0x4000080 fsleep syz-executor.0 *15229 147795 22859 0 7 0x4000000 syz-executor.0 22859 72639 27249 0 3 0x82 nanosleep syz-executor.0 9914 452088 0 0 3 0x14200 bored sosplice 4886 44843 1 0 3 0x100083 ttyin getty 7564 185252 27249 0 3 0x2 biowait syz-executor.1 27249 338692 31815 0 3 0x82 thrsleep syz-fuzzer 27249 409023 31815 0 3 0x4000082 nanosleep syz-fuzzer 27249 456325 31815 0 3 0x4000082 thrsleep syz-fuzzer 27249 27813 31815 0 3 0x4000082 thrsleep syz-fuzzer 27249 412589 31815 0 3 0x4000082 thrsleep syz-fuzzer 27249 467039 31815 0 3 0x4000082 thrsleep syz-fuzzer 27249 430516 31815 0 3 0x4000082 thrsleep syz-fuzzer 27249 441252 31815 0 3 0x4000082 thrsleep syz-fuzzer 27249 460691 31815 0 3 0x4000082 kqread syz-fuzzer 27249 102322 31815 0 3 0x4000082 thrsleep syz-fuzzer 31815 373144 77916 0 3 0x10008a pause ksh 77916 145770 54765 0 3 0x92 select sshd 54765 45779 1 0 3 0x80 select sshd 35368 452549 93334 74 3 0x100092 bpf pflogd 93334 429038 1 0 3 0x80 netio pflogd 83539 285851 63286 73 3 0x100090 kqread syslogd 63286 47676 1 0 3 0x100082 netio syslogd 96148 330753 1 77 3 0x100090 poll dhclient 37496 503241 1 0 3 0x80 poll dhclient 97532 228851 0 0 3 0x14200 pgzero zerothread 33499 283608 0 0 3 0x14200 aiodoned aiodoned 10575 280129 0 0 3 0x14200 syncer update 15759 314553 0 0 3 0x14200 cleaner cleaner 99364 459239 0 0 3 0x14200 reaper reaper 96751 250252 0 0 3 0x14200 pgdaemon pagedaemon 91194 230357 0 0 3 0x14200 bored crynlk 98910 105128 0 0 3 0x14200 bored crypto 39272 219803 0 0 3 0x40014200 acpi0 acpi0 21877 28206 0 0 3 0x40014200 idle1 22227 412730 0 0 3 0x14200 bored softnet 83251 486780 0 0 3 0x14200 bored systqmp 46017 343923 0 0 3 0x14200 bored systq 66201 499117 0 0 3 0x40014200 bored softclock 50343 274720 0 0 3 0x40014200 idle0 4112 78100 0 0 3 0x14200 bored smr 1 245713 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{0}> show all locks CPU 1: exclusive sched_lock &sched_lock r = 0 (0xffffffff8238d220) #0 witness_lock+0x52e sys/kern/subr_witness.c:1161 #1 sleep_setup+0xb4 sys/kern/kern_synch.c:281 #2 tsleep+0xe2 sys/kern/kern_synch.c:117 #3 sys_nanosleep+0x1b8 sys/kern/kern_time.c:285 #4 syscall+0x552 mi_syscall sys/sys/syscall_mi.h:99 [inline] #4 syscall+0x552 sys/arch/amd64/amd64/trap.c:574 #5 Xsyscall+0x128 Process 15229 (syz-executor.0) thread 0xffff800020b38978 (147795) exclusive rrwlock inode r = 0 (0xfffffd806fbd2b40) #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_lock+0x6e sys/kern/vfs_vnops.c:549 #5 sys_fsync+0x114 sys/kern/vfs_syscalls.c:2704 #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 22859 (syz-executor.0) thread 0xffff800020b399e0 (72639) exclusive kernel_lock &kernel_lock r = 0 (0xffffffff82340a90) #0 witness_lock+0x52e sys/kern/subr_witness.c:1161 #1 syscall+0x43a mi_syscall sys/sys/syscall_mi.h:91 [inline] #1 syscall+0x43a sys/arch/amd64/amd64/trap.c:574 #2 Xsyscall+0x128 Process 7564 (syz-executor.1) thread 0xffff800020b152c8 (185252) exclusive rrwlock inode r = 0 (0xfffffd806fbd2810) #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_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+0x575 sys/kern/vfs_lookup.c:523 #11 namei+0x45f sys/kern/vfs_lookup.c:224 #12 dounlinkat+0x99 sys/kern/vfs_syscalls.c:1673 #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 (0xfffffd806fbd2920) #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_lock+0x6e sys/kern/vfs_vnops.c:549 #5 vfs_lookup+0xec sys/kern/vfs_lookup.c:387 #6 namei+0x45f sys/kern/vfs_lookup.c:224 #7 dounlinkat+0x99 sys/kern/vfs_syscalls.c:1673 #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 9491 6396K 6781K 78643K 11620 0 0 pcb 25 9K 11K 78643K 276 0 0 rtable 108 4K 4K 78643K 310 0 0 ifaddr 49 12K 12K 78643K 92 0 0 counters 39 33K 33K 78643K 39 0 0 ioctlops 0 0K 4K 78643K 1486 0 0 iov 0 0K 12K 78643K 20 0 0 mount 1 1K 1K 78643K 1 0 0 vnodes 1208 76K 76K 78643K 1727 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 11 0 0 VM map 2 1K 1K 78643K 2 0 0 sem 12 0K 0K 78643K 40 0 0 dirhash 12 2K 2K 78643K 12 0 0 ACPI 1808 196K 290K 78643K 12628 0 0 file desc 5 13K 25K 78643K 579 0 0 sigio 0 0K 0K 78643K 6 0 0 proc 54 51K 83K 78643K 439 0 0 subproc 64 65538K 67586K 78643K 102 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 32 0 0 in_multi 33 2K 2K 78643K 62 0 0 ether_multi 1 0K 0K 78643K 4 0 0 mrt 0 0K 0K 78643K 2 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 249 0 0 pfkey data 0 0K 0K 78643K 2 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 93 21K 21K 78643K 2614 0 0 UVM aobj 12 2K 2K 78643K 15 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 5 0 0 NDP 9 0K 0K 78643K 25 0 0 temp 139 2708K 2773K 78643K 4942 0 0 kqueue 0 0K 0K 78643K 2 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 280 213 0 206 1 0 1 1 0 8 0 plimitpl 152 40 0 32 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 tcpqe 32 25 0 25 2 2 0 1 0 8 0 tcpcb 544 64 0 60 1 0 1 1 0 8 0 nd6 48 9 0 3 1 0 1 1 0 8 0 ppxss 1128 7 0 7 3 3 0 1 0 8 0 pfosfp 40 846 0 423 5 0 5 5 0 8 0 pfosfpen 112 1428 0 714 21 0 21 21 0 8 0 pfstitem 24 17 0 5 1 0 1 1 0 8 0 pfstkey 112 17 0 5 1 0 1 1 0 8 0 pfstate 328 17 0 5 1 0 1 1 0 8 0 pfrule 1360 21 0 16 2 1 1 2 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 236 0 44 12 0 12 12 0 8 0 art_table 32 237 0 44 2 0 2 2 0 8 0 art_node 16 55 0 15 1 0 1 1 0 8 0 sysvmsgpl 40 6 0 2 1 0 1 1 0 8 0 semupl 112 1 0 1 1 1 0 1 0 8 0 semapl 112 36 0 26 1 0 1 1 0 8 0 shmpl 112 13 0 3 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino1pl 128 2548 0 1128 46 0 46 46 0 8 0 ffsino 272 2548 0 1128 95 0 95 95 0 8 0 nchpl 144 3479 0 1839 61 0 61 61 0 8 0 uvmvnodes 72 2816 0 0 52 0 52 52 0 8 0 vnodes 200 2816 0 0 149 0 149 149 0 8 0 namei 1024 9601 0 9601 2 1 1 1 0 8 1 percpumem 16 30 0 0 1 0 1 1 0 8 0 scsiplug 64 1 0 1 1 1 0 1 0 8 0 scxspl 192 9234 0 9233 11 8 3 6 0 8 2 sigapl 432 776 0 761 3 1 2 3 0 8 0 futexpl 56 5502 0 5500 1 0 1 1 0 8 0 knotepl 112 158 0 139 1 0 1 1 0 8 0 kqueuepl 104 107 0 105 1 0 1 1 0 8 0 pipepl 112 374 0 355 3 2 1 2 0 8 0 fdescpl 488 777 0 761 3 0 3 3 0 8 0 filepl 152 3845 0 3736 7 2 5 6 0 8 0 lockfpl 104 425 0 423 2 1 1 1 0 8 0 lockfspl 32 190 0 189 2 1 1 1 0 8 0 sessionpl 112 20 0 9 1 0 1 1 0 8 0 pgrppl 48 22 0 11 1 0 1 1 0 8 0 ucredpl 96 529 0 520 1 0 1 1 0 8 0 zombiepl 144 761 0 761 3 2 1 1 0 8 1 processpl 840 793 0 761 4 0 4 4 0 8 0 procpl 600 1864 0 1818 4 0 4 4 0 8 0 srpgc 64 6 0 6 1 0 1 1 0 8 1 sosppl 128 3 0 3 1 1 0 1 0 8 0 sockpl 384 447 0 428 6 3 3 4 0 8 1 mcl64k 65536 5 0 0 1 0 1 1 0 8 0 mcl16k 16384 2 0 0 1 0 1 1 0 8 0 mcl12k 12288 2 0 0 1 0 1 1 0 8 0 mcl9k 9216 2 0 0 1 0 1 1 0 8 0 mcl8k 8192 1 0 0 1 0 1 1 0 8 0 mcl4k 4096 6 0 0 1 0 1 1 0 8 0 mcl2k2 2112 1 0 0 1 0 1 1 0 8 0 mcl2k 2048 126 0 0 15 0 15 15 0 8 0 mtagpl 80 1 0 0 1 0 1 1 0 8 0 mbufpl 256 160 0 0 9 0 9 9 0 8 0 bufpl 256 6615 0 1166 341 0 341 341 0 8 0 anonpl 16 75863 0 66669 65 13 52 63 0 125 5 amapchunkpl 152 4036 0 3913 9 3 6 7 0 158 0 amappl16 192 3394 0 2779 43 11 32 43 0 8 1 amappl15 184 2 0 2 1 1 0 1 0 8 0 amappl14 176 545 0 539 2 1 1 1 0 8 0 amappl13 168 31 0 29 2 1 1 1 0 8 0 amappl12 160 10 0 9 1 0 1 1 0 8 0 amappl11 152 53 0 34 1 0 1 1 0 8 0 amappl10 144 73 0 71 1 0 1 1 0 8 0 amappl9 136 619 0 615 1 0 1 1 0 8 0 amappl8 128 152 0 137 1 0 1 1 0 8 0 amappl7 120 38 0 34 1 0 1 1 0 8 0 amappl6 112 58 0 51 1 0 1 1 0 8 0 amappl5 104 132 0 117 1 0 1 1 0 8 0 amappl4 96 544 0 513 2 1 1 2 0 8 0 amappl3 88 1140 0 1131 1 0 1 1 0 8 0 amappl2 80 5552 0 5496 3 1 2 2 0 8 0 amappl1 72 26125 0 25673 25 15 10 20 0 8 0 amappl 72 2138 0 2095 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 14 0 3 1 0 1 1 0 8 0 uaddrrnd 24 777 0 761 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 777 0 761 1 0 1 1 0 8 0 vmmpekpl 168 9945 0 9922 2 0 2 2 0 8 0 vmmpepl 168 87927 0 86298 123 30 93 93 0 357 17 vmsppl 360 776 0 761 2 0 2 2 0 8 0 pdppl 4096 1562 0 1522 6 0 6 6 0 8 0 pvpl 32 246161 0 233796 166 22 144 155 0 265 25 pmappl 232 776 0 761 2 1 1 2 0 8 0 extentpl 40 39 0 25 1 0 1 1 0 8 0 phpool 112 493 0 4 14 0 14 14 0 8 0