INFO: task hung in __sb_start

INFO: task hung in __sb_start_write
Status: closed as invalid on 2018/07/13 10:38
Reported-by: syzbot+7b2866454055e43c21e5@syzkaller.appspotmail.com
First crash: 1389d, last: 1291d

duplicates (1):
Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
INFO: task hung in collapse_huge_page				352	1291d	1363d	0/22	closed as dup on 2018/06/11 10:57

similar bugs (1):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	INFO: task hung in __sb_start_write (2)				3	1231d	1230d	0/22	closed as invalid on 2018/09/17 14:02

Sample crash report:

IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready
IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready
8021q: adding VLAN 0 to HW filter on device team0
INFO: task syz-executor3:17623 blocked for more than 140 seconds.
      Not tainted 4.18.0-rc4+ #142
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor3   D23064 17623      1 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2853 [inline]
 __schedule+0x87c/0x1ed0 kernel/sched/core.c:3501
 schedule+0xfb/0x450 kernel/sched/core.c:3545
 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:269 [inline]
 rwsem_down_read_failed+0x362/0x600 kernel/locking/rwsem-xadd.c:286
 call_rwsem_down_read_failed+0x18/0x30 arch/x86/lib/rwsem.S:94
 __down_read arch/x86/include/asm/rwsem.h:83 [inline]
 __percpu_down_read+0x16e/0x210 kernel/locking/percpu-rwsem.c:85
 percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:49 [inline]
 percpu_down_read include/linux/percpu-rwsem.h:59 [inline]
 __sb_start_write+0x2d7/0x300 fs/super.c:1403
 sb_start_write include/linux/fs.h:1554 [inline]
 mnt_want_write+0x3f/0xc0 fs/namespace.c:386
 filename_create+0x13e/0x5b0 fs/namei.c:3640
 user_path_create fs/namei.c:3703 [inline]
 do_mkdirat+0xda/0x310 fs/namei.c:3842
 __do_sys_mkdir fs/namei.c:3866 [inline]
 __se_sys_mkdir fs/namei.c:3864 [inline]
 __x64_sys_mkdir+0x5c/0x80 fs/namei.c:3864
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x455267
Code: 00 00 48 8b 4c 24 78 8b 44 01 04 89 44 24 08 48 8b 84 24 c8 00 00 00 48 89 04 24 e8 53 e7 ff ff 48 8b 44 24 10 48 89 84 24 d0 <00> 00 00 48 8b 8c 24 f8 00 00 00 48 8b 54 24 78 8b 4c 0a 04 89 4c 
RSP: 002b:00007ffcbd27cc68 EFLAGS: 00000202 ORIG_RAX: 0000000000000053
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000455267
RDX: 00007ffcbd27d943 RSI: 00000000000001ff RDI: 00007ffcbd27d940
RBP: 0000000000000013 R08: 0000000000000000 R09: 0000000000000003
R10: 0000000000000064 R11: 0000000000000202 R12: 00000000000003e0
R13: 0000000000411d30 R14: 00007ffcbd27d310 R15: 0000000000000000
INFO: task syz-executor0:18035 blocked for more than 140 seconds.
      Not tainted 4.18.0-rc4+ #142
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0   D23696 18035  17552 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2853 [inline]
 __schedule+0x87c/0x1ed0 kernel/sched/core.c:3501
 schedule+0xfb/0x450 kernel/sched/core.c:3545
 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:269 [inline]
 rwsem_down_read_failed+0x362/0x600 kernel/locking/rwsem-xadd.c:286
 call_rwsem_down_read_failed+0x18/0x30 arch/x86/lib/rwsem.S:94
 __down_read arch/x86/include/asm/rwsem.h:83 [inline]
 __percpu_down_read+0x16e/0x210 kernel/locking/percpu-rwsem.c:85
 percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:49 [inline]
 percpu_down_read include/linux/percpu-rwsem.h:59 [inline]
 __sb_start_write+0x2d7/0x300 fs/super.c:1403
 sb_start_pagefault include/linux/fs.h:1583 [inline]
 ext4_page_mkwrite+0x1d0/0x1430 fs/ext4/inode.c:6126
 do_page_mkwrite+0x14e/0x520 mm/memory.c:2380
 wp_page_shared mm/memory.c:2676 [inline]
 do_wp_page+0xf78/0x19b0 mm/memory.c:2776
 handle_pte_fault mm/memory.c:3988 [inline]
 __handle_mm_fault+0x2a84/0x4460 mm/memory.c:4096
 handle_mm_fault+0x53e/0xc80 mm/memory.c:4133
 __do_page_fault+0x620/0xe50 arch/x86/mm/fault.c:1396
 do_page_fault+0xf6/0x8c0 arch/x86/mm/fault.c:1471
 page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1160
RIP: 0033:0x4084b0
Code: 24 1f e9 d2 00 00 00 48 ff c2 48 83 fa 08 0f 83 ad 00 00 00 84 01 0f b6 1c 11 38 d8 75 e9 48 89 54 24 20 48 8b 5c 24 48 0f b6 <73> 50 48 0f af f2 0f b6 5b 51 48 89 cf 48 8d 74 3e 08 84 db 74 7c 
RSP: 002b:00007fff8c66c3d0 EFLAGS: 00010287
RAX: 0000001b33622c48 RBX: 0000000000000000 RCX: 0000001b34620000
RDX: 0000001b33622c4c RSI: 0000000000730b08 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 00007fff8c66c410 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000002 R14: 000000000072bea0 R15: 000000000072bea0

Showing all locks held in the system:
1 lock held by khungtaskd/902:
 #0: 000000009016202b (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x428 kernel/locking/lockdep.c:4461
2 locks held by rs:main Q:Reg/4402:
 #0: 000000003e5710ce (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766
 #1: 00000000e2a27b0b (sb_writers#6){++++}, at: file_start_write include/linux/fs.h:2737 [inline]
 #1: 00000000e2a27b0b (sb_writers#6){++++}, at: vfs_write+0x452/0x560 fs/read_write.c:548
1 lock held by rsyslogd/4404:
 #0: 00000000aea06399 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766
2 locks held by getty/4494:
 #0: 00000000fef14939 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 00000000f7e9f043 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/4495:
 #0: 00000000d633f425 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 0000000027f47f19 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/4496:
 #0: 000000009bfe7ff6 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 000000007796213b (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/4497:
 #0: 000000003753114f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 000000007401a83a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/4498:
 #0: 0000000026d521b6 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 00000000215d1c6d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/4499:
 #0: 0000000045d08b72 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 00000000d029a8a9 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/4500:
 #0: 00000000fc3432ff (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 00000000f1a5202a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
1 lock held by syz-executor3/17623:
 #0: 00000000e2a27b0b (sb_writers#6){++++}, at: sb_start_write include/linux/fs.h:1554 [inline]
 #0: 00000000e2a27b0b (sb_writers#6){++++}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:386
2 locks held by syz-executor0/18035:
 #0: 00000000a324fcf6 (&mm->mmap_sem){++++}, at: __do_page_fault+0x389/0xe50 arch/x86/mm/fault.c:1325
 #1: 00000000a4223a1c (sb_pagefaults){++++}, at: sb_start_pagefault include/linux/fs.h:1583 [inline]
 #1: 00000000a4223a1c (sb_pagefaults){++++}, at: ext4_page_mkwrite+0x1d0/0x1430 fs/ext4/inode.c:6126

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

NMI backtrace for cpu 0
CPU: 0 PID: 902 Comm: khungtaskd Not tainted 4.18.0-rc4+ #142
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+0x1c9/0x2b4 lib/dump_stack.c:113
 nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103
 nmi_trigger_cpumask_backtrace+0x151/0x192 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_all_cpu_backtrace include/linux/nmi.h:138 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:196 [inline]
 watchdog+0x9c4/0xf80 kernel/hung_task.c:252
 kthread+0x345/0x410 kernel/kthread.c:246
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54

Crashes (1508):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report
ci-upstream-kasan-gce-root	2018/07/12 03:16	upstream	c25c74b7476e	2e0e3130	.config	log	report
ci-upstream-kasan-gce-root	2018/07/12 00:18	upstream	c25c74b7476e	2e0e3130	.config	log	report
ci-upstream-kasan-gce-root	2018/07/11 19:05	upstream	1e09177acae3	2e0e3130	.config	log	report
ci-upstream-kasan-gce-root	2018/07/11 13:51	upstream	1e09177acae3	2e0e3130	.config	log	report
ci-upstream-kasan-gce-root	2018/07/11 09:16	upstream	30c2c32d7f70	2e0e3130	.config	log	report
ci-upstream-kasan-gce-root	2018/07/11 04:44	upstream	30c2c32d7f70	2e0e3130	.config	log	report
ci-upstream-kasan-gce-root	2018/07/11 02:58	upstream	30c2c32d7f70	2e0e3130	.config	log	report
ci-upstream-kasan-gce-root	2018/07/10 18:07	upstream	092150a25cb7	9fa03fa5	.config	log	report
ci-upstream-kasan-gce-root	2018/07/10 16:42	upstream	092150a25cb7	9fa03fa5	.config	log	report
ci-upstream-kasan-gce-root	2018/07/10 13:40	upstream	092150a25cb7	9fa03fa5	.config	log	report
ci-upstream-kasan-gce-root	2018/07/10 07:25	upstream	092150a25cb7	f25e5770	.config	log	report
ci-upstream-kasan-gce-root	2018/07/10 06:53	upstream	092150a25cb7	f25e5770	.config	log	report
ci-upstream-kasan-gce-root	2018/07/10 04:31	upstream	092150a25cb7	f25e5770	.config	log	report
ci-upstream-kasan-gce-root	2018/04/05 12:29	upstream	06dd3dfeea60	5e1ccffc	.config	log	report
ci-upstream-bpf-kasan-gce	2018/07/12 10:16	bpf	6e6fddc78323	2e0e3130	.config	log	report
ci-upstream-bpf-kasan-gce	2018/07/12 05:24	bpf	61d769807f27	2e0e3130	.config	log	report
ci-upstream-bpf-kasan-gce	2018/07/12 01:52	bpf	61d769807f27	2e0e3130	.config	log	report
ci-upstream-bpf-kasan-gce	2018/07/11 21:14	bpf	61d769807f27	2e0e3130	.config	log	report
ci-upstream-bpf-kasan-gce	2018/07/11 06:44	bpf	59ee4129a279	2e0e3130	.config	log	report
ci-upstream-bpf-kasan-gce	2018/07/10 23:42	bpf	59ee4129a279	2e0e3130	.config	log	report
ci-upstream-bpf-kasan-gce	2018/07/10 23:19	bpf	59ee4129a279	2e0e3130	.config	log	report
ci-upstream-bpf-kasan-gce	2018/07/10 15:06	bpf	b9626f45abcc	9fa03fa5	.config	log	report
ci-upstream-bpf-kasan-gce	2018/07/10 12:25	bpf	b9626f45abcc	9fa03fa5	.config	log	report
ci-upstream-bpf-kasan-gce	2018/07/10 11:11	bpf	b9626f45abcc	9fa03fa5	.config	log	report
ci-upstream-bpf-next-kasan-gce	2018/07/12 04:23	bpf-next	671dffa7de7b	2e0e3130	.config	log	report
ci-upstream-bpf-next-kasan-gce	2018/07/11 22:19	bpf-next	671dffa7de7b	2e0e3130	.config	log	report
ci-upstream-bpf-next-kasan-gce	2018/07/11 20:53	bpf-next	671dffa7de7b	2e0e3130	.config	log	report
ci-upstream-bpf-next-kasan-gce	2018/07/10 22:14	bpf-next	d90c936fb318	2e0e3130	.config	log	report
ci-upstream-bpf-next-kasan-gce	2018/07/10 20:44	bpf-next	d90c936fb318	2e0e3130	.config	log	report
ci-upstream-bpf-next-kasan-gce	2018/07/10 11:03	bpf-next	d90c936fb318	9fa03fa5	.config	log	report
ci-upstream-bpf-next-kasan-gce	2018/07/10 09:59	bpf-next	d90c936fb318	9fa03fa5	.config	log	report
ci-upstream-bpf-next-kasan-gce	2018/07/10 08:53	bpf-next	d90c936fb318	9fa03fa5	.config	log	report
ci-upstream-bpf-next-kasan-gce	2018/07/10 08:42	bpf-next	d90c936fb318	9fa03fa5	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2018/07/12 10:05	linux-next	3ee15ba60e6b	2e0e3130	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2018/07/11 23:34	linux-next	98be45067040	2e0e3130	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2018/07/11 12:23	linux-next	98be45067040	2e0e3130	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2018/07/11 10:57	linux-next	98be45067040	2e0e3130	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2018/07/11 09:02	linux-next	98be45067040	2e0e3130	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2018/07/11 07:51	linux-next	98be45067040	2e0e3130	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2018/07/10 19:41	linux-next	3951bd9fe3e2	9fa03fa5	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2018/07/10 05:46	linux-next	d00d6d9a339d	f25e5770	.config	log	report