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INFO: task hung in lo_open

Status: closed as invalid on 2018/02/14 14:52
Subsystems: block
[Documentation on labels]
Reported-by: syzbot+44effc70e26d149b5c2fd1e21fb5f1d421e48d40@syzkaller.appspotmail.com
First crash: 2375d, last: 2354d
▶ ▼ Similar bugs (5)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in lo_open (2) block 10 2037d 2266d 11/28 fixed on 2019/01/15 20:25
android-44 INFO: task hung in lo_open syz 593 1654d 1888d 0/2 public: reported syz repro on 2019/04/14 00:02
android-49 INFO: task hung in lo_open C 2683 1653d 1887d 0/3 public: reported C repro on 2019/04/14 09:28
android-414 INFO: task hung in lo_open C 6143 1654d 1891d 0/1 public: reported C repro on 2019/04/11 00:00
linux-4.14 INFO: task hung in lo_open C 1230 492d 1890d 0/1 upstream: reported C repro on 2019/04/11 12:30

Sample crash report:
`)n"¢ÙõoeªV uí …ÿyüØ“Å´ZÍ«—Ã) failed (rc=-13)
INFO: task syz-executor7:25192 blocked for more than 120 seconds.
      Not tainted 4.15.0-rc6+ #245
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor7   D22496 25192   3728 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2799 [inline]
 __schedule+0x8eb/0x2060 kernel/sched/core.c:3375
 schedule+0xf5/0x430 kernel/sched/core.c:3434
 schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:3492
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0xaad/0x1a80 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 lo_open+0x1b/0xa0 drivers/block/loop.c:1571
 __blkdev_get+0x2f9/0x10e0 fs/block_dev.c:1454
 blkdev_get+0x3a1/0xad0 fs/block_dev.c:1591
 blkdev_open+0x1c9/0x250 fs/block_dev.c:1749
 do_dentry_open+0x667/0xd40 fs/open.c:752
 vfs_open+0x107/0x220 fs/open.c:866
 do_last fs/namei.c:3379 [inline]
 path_openat+0x1151/0x3530 fs/namei.c:3519
 do_filp_open+0x25b/0x3b0 fs/namei.c:3554
 do_sys_open+0x502/0x6d0 fs/open.c:1059
 SYSC_open fs/open.c:1077 [inline]
 SyS_open+0x2d/0x40 fs/open.c:1072
 entry_SYSCALL_64_fastpath+0x23/0x9a
RIP: 0033:0x40ce01
RSP: 002b:00007f30e159e780 EFLAGS: 00000293 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 000000000040ce01
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007f30e159e830
RBP: 000000000000025d R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000000c R11: 0000000000000293 R12: 00000000006f1958
R13: 00000000ffffffff R14: 00007f30e159f6d4 R15: 0000000000000000

Showing all locks held in the system:
2 locks held by khungtaskd/737:
 #0:  (rcu_read_lock){....}, at: [<000000006f908f39>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline]
 #0:  (rcu_read_lock){....}, at: [<000000006f908f39>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249
 #1:  (tasklist_lock){.+.+}, at: [<00000000042f9077>] debug_show_all_locks+0xd3/0x400 kernel/locking/lockdep.c:4464
4 locks held by rs:main Q:Reg/3342:
 #0:  (&f->f_pos_lock){+.+.}, at: [<00000000f853dcac>] __fdget_pos+0x12b/0x190 fs/file.c:770
 #1:  (sb_writers#4){.+.+}, at: [<000000008a38b9bd>] file_start_write include/linux/fs.h:2715 [inline]
 #1:  (sb_writers#4){.+.+}, at: [<000000008a38b9bd>] vfs_write+0x407/0x510 fs/read_write.c:543
 #2:  (&sb->s_type->i_mutex_key#10){+.+.}, at: [<000000009f8ae320>] inode_trylock include/linux/fs.h:733 [inline]
 #2:  (&sb->s_type->i_mutex_key#10){+.+.}, at: [<000000009f8ae320>] ext4_file_write_iter+0x21f/0x10c0 fs/ext4/file.c:232
 #3:  (jbd2_handle){++++}, at: [<0000000006f22b2b>] start_this_handle+0x488/0x1080 fs/jbd2/transaction.c:388
2 locks held by getty/3466:
 #0:  (&tty->ldisc_sem){++++}, at: [<000000009cd8de47>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<000000009edb5910>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131
2 locks held by getty/3467:
 #0:  (&tty->ldisc_sem){++++}, at: [<000000009cd8de47>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<000000009edb5910>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131
2 locks held by getty/3468:
 #0:  (&tty->ldisc_sem){++++}, at: [<000000009cd8de47>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<000000009edb5910>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131
2 locks held by getty/3469:
 #0:  (&tty->ldisc_sem){++++}, at: [<000000009cd8de47>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<000000009edb5910>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131
2 locks held by getty/3470:
 #0:  (&tty->ldisc_sem){++++}, at: [<000000009cd8de47>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<000000009edb5910>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131
2 locks held by getty/3471:
 #0:  (&tty->ldisc_sem){++++}, at: [<000000009cd8de47>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<000000009edb5910>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131
2 locks held by getty/3472:
 #0:  (&tty->ldisc_sem){++++}, at: [<000000009cd8de47>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<000000009edb5910>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131
2 locks held by syz-executor7/25192:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<00000000ef13ac42>] __blkdev_get+0x158/0x10e0 fs/block_dev.c:1439
 #1:  (loop_index_mutex){+.+.}, at: [<000000004ed20a48>] lo_open+0x1b/0xa0 drivers/block/loop.c:1571
2 locks held by syz-executor7/25210:
 #0:  (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000009f4182>] lo_ioctl+0x8b/0x1b70 drivers/block/loop.c:1355
 #1:  (&bdev->bd_mutex){+.+.}, at: [<0000000064a7467e>] blkdev_reread_part+0x1e/0x40 block/ioctl.c:192
1 lock held by syz-executor7/25223:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<00000000ef13ac42>] __blkdev_get+0x158/0x10e0 fs/block_dev.c:1439
1 lock held by syz-executor7/25226:
 #0:  (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000009f4182>] lo_ioctl+0x8b/0x1b70 drivers/block/loop.c:1355
1 lock held by syz-executor7/25228:
 #0:  (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000009f4182>] lo_ioctl+0x8b/0x1b70 drivers/block/loop.c:1355
1 lock held by syz-executor7/25230:
 #0:  (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000009f4182>] lo_ioctl+0x8b/0x1b70 drivers/block/loop.c:1355
1 lock held by syz-executor7/25231:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<00000000ef13ac42>] __blkdev_get+0x158/0x10e0 fs/block_dev.c:1439
2 locks held by blkid/25205:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<00000000ef13ac42>] __blkdev_get+0x158/0x10e0 fs/block_dev.c:1439
 #1:  (loop_index_mutex){+.+.}, at: [<000000004ed20a48>] lo_open+0x1b/0xa0 drivers/block/loop.c:1571
2 locks held by syz-executor1/25213:
 #0:  (loop_index_mutex){+.+.}, at: [<0000000037185579>] loop_control_ioctl+0x89/0x490 drivers/block/loop.c:1932
 #1:  (&lo->lo_ctl_mutex#2){+.+.}, at: [<00000000907fc6ab>] loop_control_ioctl+0x1a7/0x490 drivers/block/loop.c:1946
1 lock held by syz-executor1/25221:
 #0:  (loop_index_mutex){+.+.}, at: [<0000000037185579>] loop_control_ioctl+0x89/0x490 drivers/block/loop.c:1932

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

NMI backtrace for cpu 0
CPU: 0 PID: 737 Comm: khungtaskd Not tainted 4.15.0-rc6+ #245
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:53
 nmi_cpu_backtrace+0x1d2/0x210 lib/nmi_backtrace.c:103
 nmi_trigger_cpumask_backtrace+0x122/0x180 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_task kernel/hung_task.c:132 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline]
 watchdog+0x90c/0xd60 kernel/hung_task.c:249
 kthread+0x33c/0x400 kernel/kthread.c:238
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:524
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.15.0-rc6+ #245
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:apic_eoi arch/x86/include/asm/apic.h:406 [inline]
RIP: 0010:ack_APIC_irq arch/x86/include/asm/apic.h:450 [inline]
RIP: 0010:smp_reschedule_interrupt+0xa2/0x670 arch/x86/kernel/smp.c:262
RSP: 0018:ffff8801db307ea0 EFLAGS: 00000046
RAX: 1ffffffff0ccc62c RBX: 1ffff1003b660fd4 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 0000000000000001 RDI: ffffffff86663160
RBP: ffff8801db307fe8 R08: ffffffff86662ae8 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
R13: ffff8801db307fc0 R14: ffffffff8702ffa0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000002059000 CR3: 0000000006822001 CR4: 00000000001606e0
Call Trace:
 <IRQ>
 reschedule_interrupt+0xa9/0xb0 arch/x86/entry/entry_64.S:944
 </IRQ>
RIP: 0010:native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54
RSP: 0018:ffff8801d9f77cb0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff02
RAX: dffffc0000000000 RBX: 1ffff1003b3eef99 RCX: 0000000000000000
RDX: 1ffffffff0d19078 RSI: 0000000000000001 RDI: ffffffff868c83c0
RBP: ffff8801d9f77cb0 R08: ffffffff86662ae8 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
R13: ffff8801d9f77d68 R14: ffffffff8702ffa0 R15: 0000000000000000
 arch_safe_halt arch/x86/include/asm/paravirt.h:93 [inline]
 default_idle+0xbf/0x460 arch/x86/kernel/process.c:355
 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:346
 default_idle_call+0x36/0x90 kernel/sched/idle.c:98
 cpuidle_idle_call kernel/sched/idle.c:156 [inline]
 do_idle+0x24a/0x3b0 kernel/sched/idle.c:246
 cpu_startup_entry+0x104/0x120 kernel/sched/idle.c:351
 start_secondary+0x40a/0x590 arch/x86/kernel/smpboot.c:268
 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:237
Code: f2 f2 f2 f2 c7 40 14 00 f2 f2 f2 c7 40 18 f2 f2 f2 f2 c7 40 1c 00 f2 f2 f2 c7 40 20 f3 f3 f3 f3 48 89 f8 48 c1 e8 03 80 3c 10 00 <0f> 85 68 05 00 00 4c 8b 25 61 ea e5 00 48 b8 00 00 00 00 00 fc

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/01/02 12:30 upstream 30a7acd57389 00193447 .config console log report ci-upstream-kasan-gce
2017/12/12 17:02 upstream a638349bf6c2 414a185f .config console log report ci-upstream-kasan-gce
2017/12/14 07:54 linux-next 6084b576dca2 06ea774d .config console log report ci-upstream-next-kasan-gce
* Struck through repros no longer work on HEAD.