INFO: task hung in p9_fd

INFO: task hung in p9_fd_close
Status: upstream: reported C repro on 2019/08/30 19:28
Reported-by: syzbot+8b41a1365f1106fd0f33@syzkaller.appspotmail.com
First crash: 771d, last: 5d06h

Cause bisection: failed (bisect log)

Fix bisection: failed (bisect log)

similar bugs (3):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
linux-4.14	INFO: task hung in p9_fd_close	C		inconclusive	53	129d	773d	0/1	upstream: reported C repro on 2019/08/11 15:06
linux-4.19	INFO: task hung in p9_fd_close	C			68	4d06h	765d	0/1	upstream: reported C repro on 2019/08/19 15:52
upstream	INFO: task can't die in p9_fd_close	C	done		36	7d15h	392d	0/22	upstream: reported C repro on 2020/08/26 10:38

Sample crash report:

INFO: task syz-executor317:6541 blocked for more than 143 seconds.
      Not tainted 5.15.0-rc1-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor317 state:D stack:28120 pid: 6541 ppid:  6522 flags:0x00004004
Call Trace:
 context_switch kernel/sched/core.c:4940 [inline]
 __schedule+0x940/0x26f0 kernel/sched/core.c:6287
 schedule+0xd3/0x270 kernel/sched/core.c:6366
 schedule_timeout+0x1db/0x2a0 kernel/time/timer.c:1857
 do_wait_for_common kernel/sched/completion.c:85 [inline]
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x176/0x280 kernel/sched/completion.c:138
 __flush_work+0x56e/0xb10 kernel/workqueue.c:3083
 __cancel_work_timer+0x3f9/0x570 kernel/workqueue.c:3170
 p9_conn_destroy net/9p/trans_fd.c:886 [inline]
 p9_fd_close+0x29c/0x520 net/9p/trans_fd.c:921
 p9_client_create+0x95a/0x1110 net/9p/client.c:1073
 v9fs_session_init+0x1dd/0x17b0 fs/9p/v9fs.c:406
 v9fs_mount+0x79/0x9c0 fs/9p/vfs_super.c:126
 legacy_get_tree+0x105/0x220 fs/fs_context.c:610
 vfs_get_tree+0x89/0x2f0 fs/super.c:1498
 do_new_mount fs/namespace.c:2988 [inline]
 path_mount+0x1320/0x1fa0 fs/namespace.c:3318
 do_mount fs/namespace.c:3331 [inline]
 __do_sys_mount fs/namespace.c:3539 [inline]
 __se_sys_mount fs/namespace.c:3516 [inline]
 __x64_sys_mount+0x27f/0x300 fs/namespace.c:3516
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x445bc9
RSP: 002b:00007f3e58dd6308 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00000000004cb518 RCX: 0000000000445bc9
RDX: 0000000020000040 RSI: 0000000020000000 RDI: 0000000000000000
RBP: 00000000004cb510 R08: 00000000200001c0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004cb51c
R13: 000000000049b07c R14: 64663d736e617274 R15: 0000000000022000

Showing all locks held in the system:
5 locks held by kworker/u4:0/8:
1 lock held by khungtaskd/27:
 #0: ffffffff8b97fe20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6446
2 locks held by kworker/1:2/1050:
 #0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
 #0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline]
 #0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:634 [inline]
 #0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:661 [inline]
 #0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x8a3/0x16b0 kernel/workqueue.c:2268
 #1: ffffc90004fffdb0 ((work_completion)(&m->rq)){+.+.}-{0:0}, at: process_one_work+0x8d7/0x16b0 kernel/workqueue.c:2272
2 locks held by in:imklog/6234:
 #0: ffff88801a716870 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:990
 #1: ffffffff8b96f2a8 (syslog_lock){+.+.}-{3:3}, at: is_bpf_text_address+0x0/0x170 kernel/bpf/core.c:693

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted 5.15.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:105
 nmi_trigger_cpumask_backtrace+0x1ae/0x220 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
 watchdog+0xc1d/0xf50 kernel/hung_task.c:295
 kthread+0x3e5/0x4d0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 8 Comm: kworker/u4:0 Not tainted 5.15.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:jump_entry_key include/linux/jump_label.h:140 [inline]
RIP: 0010:__jump_label_update+0x47/0x400 kernel/jump_label.c:446
Code: 5a dc ff 4c 39 ed 0f 83 23 03 00 00 e8 62 5a dc ff 48 8d 5d 08 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03 80 3c 02 00 <0f> 85 96 03 00 00 4c 8b 65 08 4c 89 e0 48 83 e0 fc 48 01 d8 48 39
RSP: 0018:ffffc90000cd7b98 EFLAGS: 00000246
RAX: dffffc0000000000 RBX: ffffffff8b39cb78 RCX: 0000000000000000
RDX: 1ffffffff167396f RSI: ffffffff8199b37e RDI: ffffffff9026bf40
RBP: ffffffff8b39cb70 R08: 0000000000000000 R09: ffffffff9026bf43
R10: ffffffff8199b90a R11: 0000000000000000 R12: ffffffff9026bf48
R13: ffffffff8b3a2530 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007faf15382000 CR3: 000000000b68e000 CR4: 0000000000350ef0
Call Trace:
 jump_label_update+0x1d5/0x430 kernel/jump_label.c:830
 static_key_disable_cpuslocked+0x152/0x1b0 kernel/jump_label.c:207
 static_key_disable+0x16/0x20 kernel/jump_label.c:215
 toggle_allocation_gate mm/kfence/core.c:640 [inline]
 toggle_allocation_gate+0x185/0x390 mm/kfence/core.c:618
 process_one_work+0x9bf/0x16b0 kernel/workqueue.c:2297
 worker_thread+0x658/0x11f0 kernel/workqueue.c:2444
 kthread+0x3e5/0x4d0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
----------------
Code disassembly (best guess):
   0:	5a                   	pop    %rdx
   1:	dc ff                	fdivr  %st,%st(7)
   3:	4c 39 ed             	cmp    %r13,%rbp
   6:	0f 83 23 03 00 00    	jae    0x32f
   c:	e8 62 5a dc ff       	callq  0xffdc5a73
  11:	48 8d 5d 08          	lea    0x8(%rbp),%rbx
  15:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  1c:	fc ff df
  1f:	48 89 da             	mov    %rbx,%rdx
  22:	48 c1 ea 03          	shr    $0x3,%rdx
  26:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
* 2a:	0f 85 96 03 00 00    	jne    0x3c6 <-- trapping instruction
  30:	4c 8b 65 08          	mov    0x8(%rbp),%r12
  34:	4c 89 e0             	mov    %r12,%rax
  37:	48 83 e0 fc          	and    $0xfffffffffffffffc,%rax
  3b:	48 01 d8             	add    %rbx,%rax
  3e:	48                   	rex.W
  3f:	39                   	.byte 0x39

Crashes (206):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci-upstream-kasan-gce-root	2021/09/13 18:41	upstream	6880fa6c5660	3ce60af8	.config	log	report	syz	C		INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-selinux-root	2021/07/10 09:17	upstream	3dbdb38e2869	8f5a7b8c	.config	log	report	syz	C		INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-root	2020/08/21 07:07	upstream	da2968ff879b	1d75fe45	.config	log	report	syz	C
ci-upstream-kasan-gce-root	2020/04/17 15:07	upstream	7a56db0299f9	18397578	.config	log	report	syz	C
ci-upstream-kasan-gce-smack-root	2019/09/21 16:12	upstream	f97c81dc6ca5	d96e88f3	.config	log	report	syz	C
ci-upstream-kasan-gce-selinux-root	2021/09/11 13:45	upstream	926de8c4326c	5ae8508a	.config	log	report	syz			INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-smack-root	2021/09/10 19:17	upstream	bf9f243f23e6	5ae8508a	.config	log	report	syz			INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-selinux-root	2021/08/20 06:45	upstream	f87d64319e6f	b599f2fc	.config	log	report	syz			INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-selinux-root	2021/07/17 17:20	upstream	d980cc0620ae	f115ae98	.config	log	report	syz			INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-smack-root	2021/07/11 14:17	upstream	3dbdb38e2869	8f5a7b8c	.config	log	report	syz			INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-selinux-root	2021/06/26 17:46	upstream	b7050b242430	9d2ab5df	.config	log	report	syz			INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-smack-root	2021/06/03 03:00	upstream	324c92e5e0ee	0740de69	.config	log	report	syz			INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-root	2021/06/01 15:47	upstream	c2131f7e73c9	032639db	.config	log	report	syz			INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-smack-root	2021/06/01 05:21	upstream	c2131f7e73c9	032639db	.config	log	report	syz			INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-smack-root	2021/05/31 04:22	upstream	b90e90f40b4f	325a8dab	.config	log	report	syz			INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-root	2021/05/30 14:06	upstream	6799d4f2da49	325a8dab	.config	log	report	syz			INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-root	2021/05/28 17:32	upstream	97e5bf604b7a	858ea628	.config	log	report	syz			INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-root	2021/05/28 09:17	upstream	97e5bf604b7a	858ea628	.config	log	report	syz			INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-smack-root	2021/05/23 05:26	upstream	23d729263037	3c7fef33	.config	log	report	syz			INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-smack-root	2021/05/18 12:12	upstream	8ac91e6c6033	a343ba6b	.config	log	report	syz			INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-smack-root	2021/05/06 11:59	upstream	d2b6f8a17919	06c27ff5	.config	log	report	syz			INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-root	2021/05/06 03:00	upstream	d2b6f8a17919	06c27ff5	.config	log	report	syz			INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-selinux-root	2019/10/01 07:40	upstream	54ecb8f7028c	c7a4fb99	.config	log	report	syz
ci-upstream-kasan-gce-root	2019/09/30 06:39	upstream	a3c0e7b1fe1f	c1ad5441	.config	log	report	syz
ci-upstream-kasan-gce-smack-root	2019/09/29 18:01	upstream	02dc96ef6c25	c1ad5441	.config	log	report	syz
ci-upstream-kasan-gce-selinux-root	2019/09/20 21:43	upstream	574cc4539762	d96e88f3	.config	log	report	syz
ci-upstream-kasan-gce-selinux-root	2019/09/14 22:45	upstream	a7f89616b737	32d59357	.config	log	report	syz
ci-upstream-kasan-gce-smack-root	2019/08/29 10:35	upstream	6525771f58cb	fd37b39e	.config	log	report	syz
ci-upstream-linux-next-kasan-gce-root	2019/10/03 17:21	linux-next	2521ffab5375	fc17ba49	.config	log	report	syz
ci-upstream-linux-next-kasan-gce-root	2019/09/17 19:02	linux-next	f84e1c16f08d	13dcda9b	.config	log	report	syz
ci-upstream-kasan-gce-smack-root	2021/09/17 15:21	upstream	bdb575f87217	5b989942	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-root	2021/09/17 05:55	upstream	bdb575f87217	5b989942	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-smack-root	2021/09/16 01:29	upstream	b7213ffa0e58	07e953c1	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-smack-root	2021/09/15 12:55	upstream	3ca706c189db	07e953c1	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-smack-root	2021/09/14 16:06	upstream	d0ee23f9d78b	07e953c1	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-root	2021/09/14 02:47	upstream	d0ee23f9d78b	58d09404	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-smack-root	2021/09/12 20:51	upstream	f306b90c69ce	5ae8508a	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-smack-root	2021/09/12 11:12	upstream	78e709522d2c	5ae8508a	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-root	2021/09/11 03:39	upstream	926de8c4326c	5ae8508a	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-selinux-root	2021/09/09 02:19	upstream	730bf31b8fc8	e2776ee4	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-selinux-root	2021/09/08 12:37	upstream	ac08b1c68d1b	e2776ee4	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-root	2021/09/06 17:41	upstream	27151f177827	6ca60148	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-selinux-root	2021/09/05 06:46	upstream	49624efa65ac	d236a457	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-smack-root	2021/09/04 12:16	upstream	7cca308cfdc0	d236a457	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-root	2021/09/01 01:28	upstream	b91db6a0b52e	7eb7e152	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-root	2021/08/28 14:40	upstream	64b4fc45bea6	be2c130d	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-root	2021/08/28 13:25	upstream	64b4fc45bea6	be2c130d	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-root	2021/08/27 12:00	upstream	77dd11439b86	b318694d	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-smack-root	2021/08/22 18:06	upstream	1bdc3d5be7e1	b599f2fc	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-smack-root	2021/08/14 20:29	upstream	dfa377c35d70	2489ab88	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-root	2021/08/07 17:31	upstream	c9194f32bfd9	6972b106	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-smack-root	2021/08/07 14:05	upstream	c9194f32bfd9	6972b106	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-smack-root	2021/08/05 08:26	upstream	251a1524293d	7f7bb950	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-root	2021/07/22 03:33	upstream	7b6ae471e541	29c3f20f	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-root	2021/07/19 05:07	upstream	2734d6c1b1a0	f115ae98	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-root	2021/07/17 06:31	upstream	d980cc0620ae	f115ae98	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-selinux-root	2021/07/16 14:12	upstream	d936eb238744	f115ae98	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-smack-root	2021/07/15 12:29	upstream	8096acd7442e	b9a2f64e	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-root	2021/07/15 11:27	upstream	8096acd7442e	b9a2f64e	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-root	2021/07/12 21:07	upstream	7fef2edf7cc7	f415556d	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-selinux-root	2021/07/12 17:18	upstream	e73f0f0ee754	f415556d	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-selinux-root	2021/07/11 06:54	upstream	3dbdb38e2869	8f5a7b8c	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-smack-root	2021/07/06 10:52	upstream	3dbdb38e2869	6c4484eb	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-root	2021/07/05 13:31	upstream	3dbdb38e2869	55aa55c2	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-smack-root	2021/07/02 17:32	upstream	3dbdb38e2869	55aa55c2	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-smack-root	2021/06/30 17:04	upstream	007b350a5875	84fd4c77	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-smack-root	2021/06/29 14:37	upstream	233a806b00e3	9d2ab5df	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-root	2021/06/11 22:03	upstream	06af8679449d	1ba81399	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-smack-root	2021/06/01 19:02	upstream	c2131f7e73c9	032639db	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-selinux-root	2021/05/23 22:32	upstream	6ebb6814a1ef	3c7fef33	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-selinux-root	2021/05/20 16:41	upstream	c3d0e3fd41b7	c560a65d	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-root	2021/05/20 13:44	upstream	c3d0e3fd41b7	c560a65d	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-root	2021/05/19 16:19	upstream	8ac91e6c6033	a343ba6b	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-smack-root	2021/05/19 14:38	upstream	8ac91e6c6033	a343ba6b	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-selinux-root	2021/05/18 11:00	upstream	8ac91e6c6033	a343ba6b	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-selinux-root	2021/05/11 21:00	upstream	88b06399c9c7	b3c3bb8e	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-root	2021/05/10 13:02	upstream	6efb943b8616	ca873091	.config	log	report			info	INFO: task hung in p9_fd_close
ci-upstream-kasan-gce-selinux-root	2021/01/13 01:45	upstream	e609571b5ffa	0cdd6185	.config	log	report			info
ci-upstream-kasan-gce-root	2019/08/13 15:19	upstream	d45331b00ddb	8620c2c2	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/07/06 09:43	linux-next	9e50b94b3eb0	51095195	.config	log	report