witness: thread 0xffff800020b93788 exiting with the following locks held: exclusive rrwlock inode r = 0 (0xfffffd806e5af0a8) locked @ /syzkaller/managers/setuid/kernel/sys/ufs/ufs/ufs_vnops.c:1547 panic: thread 0xffff800020b93788 cannot exit while holding sleeplocks Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND 90485 65839 0 0x2 0x480 1 syz-executor0 *436871 94455 0 0x14000 0x200 0 reaper db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:399 panic() at panic+0x16c sys/kern/subr_prf.c:208 witness_thread_exit(fcd30abbefe740ff) at witness_thread_exit+0x244 sys/kern/subr_witness.c:1377 reaper(0) at reaper+0x14f sys/kern/kern_exit.c:412 end trace frame: 0x0, count: 11 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}> show panic thread 0xffff800020b93788 cannot exit while holding sleeplocks ddb{0}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:399 panic() at panic+0x16c sys/kern/subr_prf.c:208 witness_thread_exit(fcd30abbefe740ff) at witness_thread_exit+0x244 sys/kern/subr_witness.c:1377 reaper(0) at reaper+0x14f sys/kern/kern_exit.c:412 end trace frame: 0x0, count: -4 ddb{0}> show registers rdi 0 rsi 0x1 rbp 0xffff800020b67aa0 rbx 0xffff800020b67b40 rdx 0xffffffff81ec6ebb cmd0646_9_tim_udma+0x136bb rcx 0x201 rax 0x1 r8 0xffffffff8186c5d4 kprintf+0x174 r9 0x1 r10 0xd9671ddb73928432 r11 0xe3e67875b9f1a568 r12 0x3000000008 r13 0xffff800020b67ab0 r14 0x100 r15 0x1 rip 0xffffffff81d1ee38 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800020b67a90 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{0}> show proc PROC (reaper) pid=436871 stat=onproc flags process=14000 proc=200 pri=4, usrpri=51, nice=20 forw=0xffffffffffffffff, list=0xffff800020b20bb8,0xffff800020b21c30 process=0xffff800020b5a698 user=0xffff800020b62000, vmspace=0xffffffff822e8a90 estcpu=1, cpticks=3, pctcpu=0.4 user=0, sys=3, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 65839 90485 14157 0 7 0x482 syz-executor0 14157 23962 57263 0 3 0x82 thrsleep syz-execprog 14157 30953 57263 0 3 0x4000082 thrsleep syz-execprog 14157 386978 57263 0 3 0x4000082 thrsleep syz-execprog 14157 7230 57263 0 3 0x4000082 thrsleep syz-execprog 14157 49060 57263 0 3 0x4000082 kqread syz-execprog 14157 388848 57263 0 3 0x4000082 thrsleep syz-execprog 14157 438293 57263 0 3 0x4000082 thrsleep syz-execprog 14157 138755 57263 0 3 0x4000082 thrsleep syz-execprog 14157 501668 57263 0 3 0x4000082 thrsleep syz-execprog 57263 198461 40486 0 3 0x10008a pause ksh 40486 138255 14540 0 3 0x92 select sshd 99832 502534 1 0 3 0x100083 ttyin getty 14540 15487 1 0 3 0x80 select sshd 2632 199428 42953 73 3 0x100010 ffs_fsync syslogd 42953 245385 1 0 3 0x100082 netio syslogd 69451 328807 1 77 3 0x100090 poll dhclient 88477 304568 1 0 3 0x80 poll dhclient 32587 150036 0 0 3 0x14200 pgzero zerothread 68571 68289 0 0 3 0x14200 aiodoned aiodoned 68593 136836 0 0 3 0x14200 syncer update 57822 469454 0 0 3 0x14200 cleaner cleaner *94455 436871 0 0 7 0x14200 reaper 83223 350201 0 0 3 0x14200 pgdaemon pagedaemon 12610 100978 0 0 3 0x14200 bored crynlk 78264 71982 0 0 3 0x14200 bored crypto 91416 288295 0 0 3 0x40014200 acpi0 acpi0 90400 394199 0 0 3 0x40014200 idle1 9288 257585 0 0 3 0x14200 bored softnet 11078 23941 0 0 3 0x14200 bored systqmp 12521 503075 0 0 3 0x14200 bored systq 39765 426468 0 0 3 0x40014200 bored softclock 92829 284933 0 0 3 0x40014200 idle0 1 61876 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{0}> show all locks Process 2632 (syslogd) thread 0xffff800020be5c30 (199428) exclusive rrwlock inode r = 0 (0xfffffd806eb875e8) locked @ /syzkaller/managers/setuid/kernel/sys/ufs/ufs/ufs_vnops.c:1547 ddb{0}>