INFO: task can't die in p9_fd

INFO: task can't die in p9_fd_close
Status: upstream: reported C repro on 2020/08/26 10:38
Reported-by: syzbot+fbe34b643e462f65e542@syzkaller.appspotmail.com
First crash: 241d, last: 2h46m

Cause bisection: introduced by (bisect log) :
commit af3acca3e35c01920fe476f730dca7345d0a48df
Author: Daniel Baluta <daniel.baluta@nxp.com>
Date: Tue Feb 20 12:53:10 2018 +0000

ASoC: ak5558: Fix style for SPDX identifier

Crash: INFO: task hung in p9_fd_close (log)
Repro: C syz .config

similar bugs (3):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	INFO: task hung in p9_fd_close	C	error	error	124	17m	599d	0/22	upstream: reported C repro on 2019/08/30 19:28
linux-4.14	INFO: task hung in p9_fd_close	C		inconclusive	52	6d22h	618d	0/1	upstream: reported C repro on 2019/08/11 15:06
linux-4.19	INFO: task hung in p9_fd_close	C			47	4d03h	610d	0/1	upstream: reported C repro on 2019/08/19 15:52

Sample crash report:

INFO: task syz-executor475:7005 can't die for more than 143 seconds.
task:syz-executor475 state:D stack:27208 pid: 7005 ppid:  6875 flags:0x00004004
Call Trace:
 context_switch kernel/sched/core.c:3778 [inline]
 __schedule+0x8e5/0x21e0 kernel/sched/core.c:4527
 schedule+0xd0/0x2a0 kernel/sched/core.c:4602
 schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1855
 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+0x163/0x260 kernel/sched/completion.c:138
 __flush_work+0x51f/0xab0 kernel/workqueue.c:3046
 __cancel_work_timer+0x5de/0x700 kernel/workqueue.c:3133
 p9_conn_destroy net/9p/trans_fd.c:889 [inline]
 p9_fd_close+0x305/0x520 net/9p/trans_fd.c:919
 p9_client_destroy+0xbe/0x360 net/9p/client.c:1086
 v9fs_session_close+0x45/0x2c0 fs/9p/v9fs.c:498
 v9fs_kill_super+0x49/0x90 fs/9p/vfs_super.c:222
 deactivate_locked_super+0x94/0x160 fs/super.c:335
 v9fs_mount+0x77c/0x970 fs/9p/vfs_super.c:203
 legacy_get_tree+0x105/0x220 fs/fs_context.c:592
 vfs_get_tree+0x89/0x2f0 fs/super.c:1547
 do_new_mount fs/namespace.c:2896 [inline]
 path_mount+0x1287/0x1e20 fs/namespace.c:3214
 do_mount fs/namespace.c:3227 [inline]
 __do_sys_mount fs/namespace.c:3435 [inline]
 __se_sys_mount fs/namespace.c:3412 [inline]
 __x64_sys_mount+0x27f/0x300 fs/namespace.c:3412
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x446eb9
Code: Bad RIP value.
RSP: 002b:00007f6a133add98 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00000000006dcc48 RCX: 0000000000446eb9
RDX: 0000000020000200 RSI: 0000000020000000 RDI: 0000000000000000
RBP: 00000000006dcc40 R08: 00000000200028c0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dcc4c
R13: 00000000200003c0 R14: 00000000004af538 R15: 0000000000000000
INFO: task syz-executor475:7005 blocked for more than 143 seconds.
      Not tainted 5.9.0-rc1-next-20200821-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor475 state:D stack:27208 pid: 7005 ppid:  6875 flags:0x00004004
Call Trace:
 context_switch kernel/sched/core.c:3778 [inline]
 __schedule+0x8e5/0x21e0 kernel/sched/core.c:4527
 schedule+0xd0/0x2a0 kernel/sched/core.c:4602
 schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1855
 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+0x163/0x260 kernel/sched/completion.c:138
 __flush_work+0x51f/0xab0 kernel/workqueue.c:3046
 __cancel_work_timer+0x5de/0x700 kernel/workqueue.c:3133
 p9_conn_destroy net/9p/trans_fd.c:889 [inline]
 p9_fd_close+0x305/0x520 net/9p/trans_fd.c:919
 p9_client_destroy+0xbe/0x360 net/9p/client.c:1086
 v9fs_session_close+0x45/0x2c0 fs/9p/v9fs.c:498
 v9fs_kill_super+0x49/0x90 fs/9p/vfs_super.c:222
 deactivate_locked_super+0x94/0x160 fs/super.c:335
 v9fs_mount+0x77c/0x970 fs/9p/vfs_super.c:203
 legacy_get_tree+0x105/0x220 fs/fs_context.c:592
 vfs_get_tree+0x89/0x2f0 fs/super.c:1547
 do_new_mount fs/namespace.c:2896 [inline]
 path_mount+0x1287/0x1e20 fs/namespace.c:3214
 do_mount fs/namespace.c:3227 [inline]
 __do_sys_mount fs/namespace.c:3435 [inline]
 __se_sys_mount fs/namespace.c:3412 [inline]
 __x64_sys_mount+0x27f/0x300 fs/namespace.c:3412
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x446eb9
Code: Bad RIP value.
RSP: 002b:00007f6a133add98 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00000000006dcc48 RCX: 0000000000446eb9
RDX: 0000000020000200 RSI: 0000000020000000 RDI: 0000000000000000
RBP: 00000000006dcc40 R08: 00000000200028c0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dcc4c
R13: 00000000200003c0 R14: 00000000004af538 R15: 0000000000000000

Showing all locks held in the system:
1 lock held by khungtaskd/1173:
 #0: ffffffff89c675c0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5825
1 lock held by in:imklog/6540:
2 locks held by kworker/0:1/6858:
 #0: ffff8880ae635dd8 (&rq->lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1292 [inline]
 #0: ffff8880ae635dd8 (&rq->lock){-.-.}-{2:2}, at: __schedule+0x232/0x21e0 kernel/sched/core.c:4445
 #1: ffff8880ae620ec8 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x2fb/0x400 kernel/sched/psi.c:833
2 locks held by kworker/0:2/6898:
 #0: ffff8880aa063d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff8880aa063d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
 #0: ffff8880aa063d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
 #0: ffff8880aa063d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
 #0: ffff8880aa063d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
 #0: ffff8880aa063d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240
 #1: ffffc90005577da8 ((work_completion)(&m->wq)){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244
1 lock held by syz-executor475/6960:
 #0: ffff8880a7c7a0e0 (&type->s_umount_key#45/1){+.+.}-{3:3}, at: alloc_super+0x201/0xa90 fs/super.c:229
1 lock held by syz-executor475/7064:
 #0: ffff8880a6c9c0e0 (&type->s_umount_key#45/1){+.+.}-{3:3}, at: alloc_super+0x201/0xa90 fs/super.c:229
2 locks held by kworker/0:3/7070:
 #0: ffff8880aa073538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff8880aa073538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
 #0: ffff8880aa073538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
 #0: ffff8880aa073538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
 #0: ffff8880aa073538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
 #0: ffff8880aa073538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240
 #1: ffffc90006157da8 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244
1 lock held by syz-executor475/7279:
 #0: ffff88809476e0e0 (&type->s_umount_key#45/1){+.+.}-{3:3}, at: alloc_super+0x201/0xa90 fs/super.c:229
1 lock held by syz-executor475/32328:
 #0: ffffffff89c6bc28 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
 #0: ffffffff89c6bc28 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x274/0x5f0 kernel/rcu/tree_exp.h:836
1 lock held by syz-executor475/32335:
 #0: ffffffff89c6bc28 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
 #0: ffffffff89c6bc28 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x274/0x5f0 kernel/rcu/tree_exp.h:836

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

NMI backtrace for cpu 1
CPU: 1 PID: 1173 Comm: khungtaskd Not tainted 5.9.0-rc1-next-20200821-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x18f/0x20d lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105
 nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:147 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:253 [inline]
 watchdog+0xd89/0xf30 kernel/hung_task.c:339
 kthread+0x3b5/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 32335 Comm: syz-executor475 Not tainted 5.9.0-rc1-next-20200821-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:write_comp_data+0x0/0x80 kernel/kcov.c:212
Code: e8 ff ff cc cc cc cc cc cc cc 65 48 8b 04 25 c0 fe 01 00 48 8b 80 20 14 00 00 c3 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 <49> 89 f2 65 8b 05 76 90 8d 7e 65 48 8b 34 25 c0 fe 01 00 a9 00 01
RSP: 0018:ffffc90009c47ab8 EFLAGS: 00000086
RAX: 0000000000000000 RBX: ffff888096e0e000 RCX: ffffffff8134b5d6
RDX: ffff888116e0e000 RSI: ffff888096e0e000 RDI: 0000000000000006
RBP: ffff888116e0e000 R08: 0000000000000001 R09: ffff8880ae736dc7
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
R13: ffff888096e0e000 R14: ffff8880ae632c80 R15: ffff8880a43f9f00
FS:  00007f6a133ae700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f19a2450710 CR3: 0000000097214000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __phys_addr+0x26/0x110 arch/x86/mm/physaddr.c:20
 virt_to_head_page include/linux/mm.h:846 [inline]
 qlink_to_cache mm/kasan/quarantine.c:128 [inline]
 qlist_move_cache+0x72/0xd0 mm/kasan/quarantine.c:278
 per_cpu_remove_cache+0x47/0x60 mm/kasan/quarantine.c:296
 on_each_cpu+0xf0/0x240 kernel/smp.c:834
 quarantine_remove_cache+0x40/0xd0 mm/kasan/quarantine.c:313
 shutdown_cache mm/slab_common.c:449 [inline]
 kmem_cache_destroy+0x50/0x120 mm/slab_common.c:497
 p9_client_destroy+0x24b/0x360 net/9p/client.c:1097
 v9fs_session_close+0x45/0x2c0 fs/9p/v9fs.c:498
 v9fs_kill_super+0x49/0x90 fs/9p/vfs_super.c:222
 deactivate_locked_super+0x94/0x160 fs/super.c:335
 v9fs_mount+0x77c/0x970 fs/9p/vfs_super.c:203
 legacy_get_tree+0x105/0x220 fs/fs_context.c:592
 vfs_get_tree+0x89/0x2f0 fs/super.c:1547
 do_new_mount fs/namespace.c:2896 [inline]
 path_mount+0x1287/0x1e20 fs/namespace.c:3214
 do_mount fs/namespace.c:3227 [inline]
 __do_sys_mount fs/namespace.c:3435 [inline]
 __se_sys_mount fs/namespace.c:3412 [inline]
 __x64_sys_mount+0x27f/0x300 fs/namespace.c:3412
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x446eb9
Code: e8 dc e6 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 ab 05 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f6a133add98 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00000000006dcc48 RCX: 0000000000446eb9
RDX: 0000000020000200 RSI: 0000000020000000 RDI: 0000000000000000
RBP: 00000000006dcc40 R08: 00000000200028c0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dcc4c
R13: 00000000200003c0 R14: 00000000004af538 R15: 0000000000000000

Crashes (19):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci-upstream-linux-next-kasan-gce-root	2020/08/22 10:34	linux-next	494d311a	6436ce4b	.config	log	report	syz	C
ci-upstream-linux-next-kasan-gce-root	2021/04/21 04:47	linux-next	1216f02e	c0ced557	.config	log	report			info	INFO: task can't die in p9_fd_close
ci-upstream-linux-next-kasan-gce-root	2021/04/13 16:02	linux-next	dcf1b51d	bfeda1b1	.config	log	report			info	INFO: task can't die in p9_fd_close
ci-upstream-linux-next-kasan-gce-root	2021/04/13 08:42	linux-next	5df924d1	bfeda1b1	.config	log	report			info	INFO: task can't die in p9_fd_close
ci-upstream-linux-next-kasan-gce-root	2021/04/03 10:22	linux-next	454c576c	6a81331a	.config	log	report			info	INFO: task can't die in p9_fd_close
ci-upstream-linux-next-kasan-gce-root	2021/04/01 17:53	linux-next	454c576c	6a81331a	.config	log	report			info	INFO: task can't die in p9_fd_close
ci-upstream-linux-next-kasan-gce-root	2021/03/22 15:32	linux-next	e3128d2f	bea32f74	.config	log	report			info	INFO: task can't die in p9_fd_close
ci-upstream-linux-next-kasan-gce-root	2021/02/24 16:30	linux-next	577c2835	fcc6d71b	.config	log	report			info	INFO: task can't die in p9_fd_close
ci-upstream-linux-next-kasan-gce-root	2021/01/14 01:52	linux-next	aa515cdc	269d24e8	.config	log	report			info
ci-upstream-linux-next-kasan-gce-root	2021/01/13 14:10	linux-next	aa515cdc	a945f0a3	.config	log	report			info
ci-upstream-linux-next-kasan-gce-root	2021/01/12 23:15	linux-next	df869cab	0cdd6185	.config	log	report			info
ci-upstream-linux-next-kasan-gce-root	2021/01/11 04:12	linux-next	1c925d20	2c1f2513	.config	log	report			info
ci-upstream-linux-next-kasan-gce-root	2021/01/03 06:42	linux-next	d7a03a44	79264ae3	.config	log	report			info
ci-upstream-linux-next-kasan-gce-root	2021/01/02 16:16	linux-next	d7a03a44	79264ae3	.config	log	report			info
ci-upstream-linux-next-kasan-gce-root	2020/12/13 18:01	linux-next	14240d4c	bca53db9	.config	log	report			info
ci-upstream-linux-next-kasan-gce-root	2020/12/08 12:06	linux-next	15ac8fdb	51a9082e	.config	log	report			info
ci-upstream-linux-next-kasan-gce-root	2020/12/06 14:44	linux-next	0eedceaf	f12ba0c5	.config	log	report			info
ci-upstream-linux-next-kasan-gce-root	2020/11/29 20:10	linux-next	6174f052	a0092f9d	.config	log	report			info
ci-upstream-linux-next-kasan-gce-root	2020/11/22 08:18	linux-next	95065cb5	0d27f508	.config	log	report			info