syzbot


INFO: task hung in ext4_file_write_iter

Status: auto-closed as invalid on 2019/08/02 09:02
Subsystems: ext4
[Documentation on labels]
Reported-by: syzbot+ef7ef285f528e7ccbbcc@syzkaller.appspotmail.com
First crash: 2180d, last: 1907d
Duplicate bugs (1)
duplicates (1):
Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
INFO: task hung in ext4_direct_IO ext4 1 2173d 2172d 0/26 closed as dup on 2018/07/18 11:49
Discussions (1)
Title Replies (including bot) Last reply
INFO: task hung in ext4_file_write_iter 0 (1) 2018/05/07 15:46
Similar bugs (5)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-44 INFO: task hung in ext4_file_write_iter 1 1710d 1710d 0/2 auto-closed as invalid on 2019/12/17 11:11
android-414 INFO: task hung in ext4_file_write_iter 6 1846d 1839d 0/1 auto-closed as invalid on 2019/10/03 05:16
upstream INFO: task hung in ext4_file_write_iter (4) ext4 2 380d 392d 0/26 auto-obsoleted due to no activity on 2023/07/09 14:32
upstream INFO: task hung in ext4_file_write_iter (3) ext4 1 492d 492d 0/26 auto-obsoleted due to no activity on 2023/03/28 01:11
upstream INFO: task hung in ext4_file_write_iter (2) ext4 1 1225d 1225d 0/26 auto-closed as invalid on 2021/03/16 20:08

Sample crash report:
INFO: task syz-executor5:30961 blocked for more than 140 seconds.
      Not tainted 5.0.0-rc4+ #58
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor5   D29776 30961  11966 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2844 [inline]
 __schedule+0x817/0x1cc0 kernel/sched/core.c:3485
 schedule+0x92/0x180 kernel/sched/core.c:3529
 __rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:584 [inline]
 rwsem_down_write_failed+0x774/0xc30 kernel/locking/rwsem-xadd.c:613
 call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:117
 __down_write arch/x86/include/asm/rwsem.h:142 [inline]
 down_write+0x53/0x90 kernel/locking/rwsem.c:72
 inode_lock include/linux/fs.h:757 [inline]
 ext4_file_write_iter+0x2ba/0x1160 fs/ext4/file.c:235
 call_write_iter include/linux/fs.h:1863 [inline]
 new_sync_write fs/read_write.c:474 [inline]
 __vfs_write+0x613/0x8e0 fs/read_write.c:487
 vfs_write+0x20c/0x580 fs/read_write.c:549
 ksys_write+0xea/0x1f0 fs/read_write.c:598
 __do_sys_write fs/read_write.c:610 [inline]
 __se_sys_write fs/read_write.c:607 [inline]
 __x64_sys_write+0x73/0xb0 fs/read_write.c:607
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457e39
Code: Bad RIP value.
RSP: 002b:00007f5a6e234c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457e39
RDX: 0000000000000020 RSI: 0000000020000140 RDI: 0000000000000004
RBP: 000000000073c040 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5a6e2356d4
R13: 00000000004cd6d8 R14: 00000000004dc860 R15: 00000000ffffffff

Showing all locks held in the system:
1 lock held by khungtaskd/1040:
 #0: 00000000957e6c00 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:4389
3 locks held by rs:main Q:Reg/7903:
 #0: 000000003b267058 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:795
 #1: 00000000288c34ef (sb_writers#4){.+.+}, at: file_start_write include/linux/fs.h:2816 [inline]
 #1: 00000000288c34ef (sb_writers#4){.+.+}, at: vfs_write+0x429/0x580 fs/read_write.c:548
 #2: 0000000074f2be59 (&sb->s_type->i_mutex_key#9){++++}, at: inode_trylock include/linux/fs.h:777 [inline]
 #2: 0000000074f2be59 (&sb->s_type->i_mutex_key#9){++++}, at: ext4_file_write_iter+0x250/0x1160 fs/ext4/file.c:232
2 locks held by getty/8028:
 #0: 0000000009437fd0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341
 #1: 000000001b9c58ca (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2154
2 locks held by getty/8029:
 #0: 00000000c85234a3 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341
 #1: 000000000cc7a95b (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2154
2 locks held by getty/8030:
 #0: 0000000014d0b9c8 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341
 #1: 00000000e99e3e7d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2154
2 locks held by getty/8031:
 #0: 00000000f9961ca4 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341
 #1: 0000000096037d3d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2154
2 locks held by getty/8032:
 #0: 00000000041ed78b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341
 #1: 0000000043cf130e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2154
2 locks held by getty/8033:
 #0: 0000000012a6e89b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341
 #1: 000000006d3418c3 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2154
2 locks held by getty/8034:
 #0: 00000000c411f6a0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341
 #1: 000000005a811bb9 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2154
4 locks held by kworker/1:3/8076:
 #0: 00000000af17297c ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:220 [inline]
 #0: 00000000af17297c ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: 00000000af17297c ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline]
 #0: 00000000af17297c ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline]
 #0: 00000000af17297c ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline]
 #0: 00000000af17297c ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0: 00000000af17297c ((wq_completion)"events"){+.+.}, at: process_one_work+0x87e/0x1790 kernel/workqueue.c:2144
 #1: 00000000a23693b1 ((work_completion)(&m->wq)){+.+.}, at: process_one_work+0x8b4/0x1790 kernel/workqueue.c:2148
 #2: 00000000288c34ef (sb_writers#4){.+.+}, at: file_start_write include/linux/fs.h:2816 [inline]
 #2: 00000000288c34ef (sb_writers#4){.+.+}, at: vfs_write+0x429/0x580 fs/read_write.c:548
 #3: 00000000dffb9f82 (&sb->s_type->i_mutex_key#9){++++}, at: inode_lock include/linux/fs.h:757 [inline]
 #3: 00000000dffb9f82 (&sb->s_type->i_mutex_key#9){++++}, at: ext4_file_write_iter+0x2ba/0x1160 fs/ext4/file.c:235
3 locks held by syz-executor5/30961:
 #0: 00000000e0373095 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:795
 #1: 00000000288c34ef (sb_writers#4){.+.+}, at: file_start_write include/linux/fs.h:2816 [inline]
 #1: 00000000288c34ef (sb_writers#4){.+.+}, at: vfs_write+0x429/0x580 fs/read_write.c:548
 #2: 00000000dffb9f82 (&sb->s_type->i_mutex_key#9){++++}, at: inode_lock include/linux/fs.h:757 [inline]
 #2: 00000000dffb9f82 (&sb->s_type->i_mutex_key#9){++++}, at: ext4_file_write_iter+0x2ba/0x1160 fs/ext4/file.c:235

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

NMI backtrace for cpu 1
CPU: 1 PID: 1040 Comm: khungtaskd Not tainted 5.0.0-rc4+ #58
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+0x172/0x1f0 lib/dump_stack.c:113
 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1be/0x236 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:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline]
 watchdog+0x9df/0xee0 kernel/hung_task.c:287
 kthread+0x357/0x430 kernel/kthread.c:246
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 3866 Comm: udevd Not tainted 5.0.0-rc4+ #58
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:rdtsc arch/x86/include/asm/msr.h:207 [inline]
RIP: 0010:rdtsc_ordered arch/x86/include/asm/msr.h:232 [inline]
RIP: 0010:pvclock_clocksource_read+0xc7/0x4d0 arch/x86/kernel/pvclock.c:87
Code: 89 c0 4c 8d 53 10 4d 89 ce 48 c1 e8 03 4c 8d 7b 1d 49 c1 ee 03 4c 01 e0 4d 01 e6 48 89 45 b8 83 e1 fe 89 4d c8 0f ae e8 0f 31 <48> c1 e2 20 48 8b 7d b0 4c 89 ce 48 09 d0 41 0f b6 16 83 e6 07 48
RSP: 0018:ffff888095b3fbb8 EFLAGS: 00000206
RAX: 0000000076dd2f36 RBX: ffffffff89997000 RCX: 0000000000000014
RDX: 0000000000000496 RSI: ffffffff81617233 RDI: ffffffff89997000
RBP: ffff888095b3fc40 R08: ffffffff8999701c R09: ffffffff89997008
R10: ffffffff89997010 R11: 0000000000000000 R12: dffffc0000000000
R13: ffffffff89997003 R14: fffffbfff1332e01 R15: ffffffff8999701d
FS:  00007f22f8b637a0(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000011021c8 CR3: 000000009593b000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 kvm_clock_read+0x18/0x30 arch/x86/kernel/kvmclock.c:90
 kvm_clock_get_cycles+0x9/0x10 arch/x86/kernel/kvmclock.c:97
 tk_clock_read kernel/time/timekeeping.c:167 [inline]
 timekeeping_get_delta kernel/time/timekeeping.c:261 [inline]
 timekeeping_get_ns kernel/time/timekeeping.c:368 [inline]
 ktime_get_ts64+0x1b0/0x3f0 kernel/time/timekeeping.c:885
 ep_set_mstimeout fs/eventpoll.c:1726 [inline]
 ep_poll+0x36a/0xe50 fs/eventpoll.c:1759
 do_epoll_wait+0x1b3/0x200 fs/eventpoll.c:2216
 __do_sys_epoll_wait fs/eventpoll.c:2226 [inline]
 __se_sys_epoll_wait fs/eventpoll.c:2223 [inline]
 __x64_sys_epoll_wait+0x97/0xf0 fs/eventpoll.c:2223
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f22f8277943
Code: 00 31 d2 48 29 c2 64 89 11 48 83 c8 ff eb ea 90 90 90 90 90 90 90 90 83 3d b5 dc 2a 00 00 75 13 49 89 ca b8 e8 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 34 c3 48 83 ec 08 e8 3b c4 00 00 48 89 04 24
RSP: 002b:00007ffffae5d1f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e8
RAX: ffffffffffffffda RBX: 0000000000000bb8 RCX: 00007f22f8277943
RDX: 0000000000000008 RSI: 00007ffffae5d2f0 RDI: 000000000000000a
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000bb8 R11: 0000000000000246 R12: 0000000000000003
R13: 0000000000000000 R14: 0000000001915940 R15: 00000000018fb030

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/02/03 09:01 upstream 12491ed354d2 c198d5dd .config console log report ci-upstream-kasan-gce-selinux-root
2018/05/07 01:42 upstream 701e39d05119 a211da1a .config console log report ci-upstream-kasan-gce
2018/10/19 09:52 net-next-old 3a3295bfa6f4 9aba67b5 .config console log report ci-upstream-net-kasan-gce
2018/10/11 12:39 net-next-old b7ec45a868af 5f818b4b .config console log report ci-upstream-net-kasan-gce
* Struck through repros no longer work on HEAD.