witness: thread exiting with locks held

[openbsd] witness: thread exiting with locks held
Status: upstream: reported syz repro on 2019/01/28 21:04
Reported-by: syzbot+9938f8e87064d4a6b361@syzkaller.appspotmail.com
First crash: 21d, last: 3h42m

duplicates:
Title	Repro	Count	Last	Reported	Patched	Status
panic: thread ADDR cannotW ARexNiIt NGw:h ilSPeL h oNlOTdi nLgO WsElReEepD lOoNck sSY		1	18d	18d	0/3	closed as dup on 2019/02/01 06:52
panic: thread ADDR cannot exit while holding sleeplocks	syz	21	21d	22d	0/3	closed as dup on 2019/01/28 21:07

Sample crash report:

login: witness: thread 0xffff800020be5078 exiting with the following locks held:
exclusive rrwlock inode r = 0 (0xfffffd806d38f0a8) locked @ /syzkaller/managers/multicore/kernel/sys/ufs/ufs/ufs_vnops.c:1547
panic: thread 0xffff800020be5078 cannot exit while holding sleeplocks
Stopped at      db_enter+0x18:  addq    $0x8,%rsp
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
 269727  25430     73    0x100010          0    0  syslogd
* 26549  44126      0     0x14000      0x200    1  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(c47ebb29993326db) 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{1}> 
ddb{1}> set $lines = 0
ddb{1}> show panic
thread 0xffff800020be5078 cannot exit while holding sleeplocks
ddb{1}> 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(c47ebb29993326db) 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{1}> show registers
rdi                                0
rsi                              0x1
rbp               0xffff800020b674f0
rbx               0xffff800020b67590
rdx               0xffffffff81f33250    cy_pio_rec+0x41b4
rcx                            0x201
rax                              0x1
r8                0xffffffff81df7814    kprintf+0x174
r9                               0x1
r10               0x85db9422cdeed693
r11               0xb911823ec3742b12
r12                     0x3000000008
r13               0xffff800020b67500
r14                            0x100
r15                              0x1
rip               0xffffffff8100c2e8    db_enter+0x18
cs                               0x8
rflags                         0x246
rsp               0xffff800020b674e0
ss                              0x10
db_enter+0x18:  addq    $0x8,%rsp
ddb{1}>

All crashes (206):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro
ci-openbsd-multicore	2019/01/29 01:11	openbsd	fabafa7b	aa432daf	.config	log	report	syz
ci-openbsd-multicore	2019/02/01 04:50	openbsd	dc36d2c7	aa432daf	.config	log	report	syz
ci-openbsd-setuid	2019/01/30 00:47	openbsd	906b732f	aa432daf	.config	log	report	syz
ci-openbsd-setuid	2019/01/29 21:54	openbsd	81059776	aa432daf	.config	log	report	syz
ci-openbsd-multicore	2019/01/29 20:15	openbsd	81059776	aa432daf	.config	log	report	syz
ci-openbsd-multicore	2019/01/29 18:37	openbsd	81059776	aa432daf	.config	log	report	syz
ci-openbsd-multicore	2019/01/29 13:00	openbsd	81059776	aa432daf	.config	log	report	syz
ci-openbsd-multicore	2019/01/29 11:04	openbsd	81059776	aa432daf	.config	log	report	syz
ci-openbsd-setuid	2019/01/29 08:04	openbsd	fabafa7b	aa432daf	.config	log	report	syz
ci-openbsd-setuid	2019/01/29 07:32	openbsd	fabafa7b	aa432daf	.config	log	report	syz
ci-openbsd-setuid	2019/01/29 01:58	openbsd	fabafa7b	aa432daf	.config	log	report	syz
ci-openbsd-setuid	2019/01/28 21:03	openbsd	fabafa7b	aa432daf	.config	log	report
ci-openbsd-setuid	2019/02/19 16:19	openbsd	77a2d566	4df543c9	.config	log	report
ci-openbsd-multicore	2019/02/19 03:41	openbsd	9c4fc159	59f36113	.config	log	report
ci-openbsd-setuid	2019/02/19 01:13	openbsd	9c4fc159	59f36113	.config	log	report
ci-openbsd-setuid	2019/02/18 19:38	openbsd	9c4fc159	59f36113	.config	log	report
ci-openbsd-setuid	2019/02/18 13:57	openbsd	9a540fb6	59f36113	.config	log	report
ci-openbsd-setuid	2019/02/18 06:00	openbsd	9a540fb6	59f36113	.config	log	report
ci-openbsd-setuid	2019/02/17 16:19	openbsd	3748d632	3e98cc30	.config	log	report
ci-openbsd-setuid	2019/02/17 14:44	openbsd	3748d632	3e98cc30	.config	log	report
ci-openbsd-multicore	2019/02/17 00:32	openbsd	f4f0873d	f42dee6d	.config	log	report
ci-openbsd-setuid	2019/02/16 22:03	openbsd	f4f0873d	f42dee6d	.config	log	report
ci-openbsd-setuid	2019/02/16 17:33	openbsd	f4f0873d	f42dee6d	.config	log	report
ci-openbsd-multicore	2019/02/16 16:13	openbsd	f4f0873d	f42dee6d	.config	log	report
ci-openbsd-setuid	2019/02/16 12:21	openbsd	f4f0873d	f42dee6d	.config	log	report
ci-openbsd-setuid	2019/02/16 08:44	openbsd	9a029001	f42dee6d	.config	log	report
ci-openbsd-setuid	2019/02/16 03:36	openbsd	9a029001	f42dee6d	.config	log	report
ci-openbsd-setuid	2019/02/15 21:14	openbsd	64a70754	f6f233c0	.config	log	report
ci-openbsd-multicore	2019/02/15 16:42	openbsd	64a70754	f6f233c0	.config	log	report
ci-openbsd-setuid	2019/02/15 09:40	openbsd	64a70754	76dd003f	.config	log	report
ci-openbsd-multicore	2019/02/14 18:04	openbsd	12d12f75	76dd003f	.config	log	report
ci-openbsd-setuid	2019/02/14 15:40	openbsd	12d12f75	76dd003f	.config	log	report
ci-openbsd-setuid	2019/02/14 14:07	openbsd	296ad859	6a46f448	.config	log	report
ci-openbsd-setuid	2019/02/14 12:45	openbsd	296ad859	6a46f448	.config	log	report
ci-openbsd-setuid	2019/02/14 10:53	openbsd	296ad859	6a46f448	.config	log	report
ci-openbsd-multicore	2019/02/14 00:39	openbsd	47f3b7d8	0a49c954	.config	log	report
ci-openbsd-multicore	2019/02/13 23:24	openbsd	47f3b7d8	0a49c954	.config	log	report
ci-openbsd-setuid	2019/02/13 17:51	openbsd	47f3b7d8	0a49c954	.config	log	report
ci-openbsd-setuid	2019/02/13 14:43	openbsd	fe67560f	1eedba36	.config	log	report
ci-openbsd-setuid	2019/02/13 13:39	openbsd	fe67560f	1eedba36	.config	log	report
ci-openbsd-setuid	2019/02/13 10:39	openbsd	fe67560f	1eedba36	.config	log	report
ci-openbsd-multicore	2019/02/13 08:48	openbsd	fe67560f	1eedba36	.config	log	report
ci-openbsd-multicore	2019/02/13 06:51	openbsd	fe67560f	1eedba36	.config	log	report
ci-openbsd-setuid	2019/02/13 03:44	openbsd	fe67560f	1eedba36	.config	log	report
ci-openbsd-setuid	2019/02/13 02:04	openbsd	fe67560f	1eedba36	.config	log	report
ci-openbsd-multicore	2019/02/12 23:34	openbsd	9a16e850	6ecc6d0f	.config	log	report
ci-openbsd-multicore	2019/02/12 15:19	openbsd	9a16e850	6ecc6d0f	.config	log	report
ci-openbsd-multicore	2019/02/12 01:11	openbsd	2a8cd46f	65a0d619	.config	log	report
ci-openbsd-setuid	2019/02/11 22:48	openbsd	2a8cd46f	65a0d619	.config	log	report
ci-openbsd-setuid	2019/02/11 19:56	openbsd	c14615c1	73f5f452	.config	log	report
ci-openbsd-setuid	2019/02/11 08:49	openbsd	c14615c1	b4f792e4	.config	log	report
ci-openbsd-setuid	2019/02/11 05:40	openbsd	d1b04a40	b4f792e4	.config	log	report
ci-openbsd-setuid	2019/02/11 01:54	openbsd	d1b04a40	b4f792e4	.config	log	report
ci-openbsd-setuid	2019/02/10 22:30	openbsd	d1b04a40	b4f792e4	.config	log	report
ci-openbsd-multicore	2019/02/10 19:55	openbsd	d1b04a40	b4f792e4	.config	log	report
ci-openbsd-setuid	2019/02/10 15:58	openbsd	515cae5b	b4f792e4	.config	log	report
ci-openbsd-multicore	2019/02/10 14:34	openbsd	515cae5b	b4f792e4	.config	log	report