INFO: task hung in lo_release (2)
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syzbot
Nov 5, 2019, 5:03:10 AM11/5/19
to syzkaller-a...@googlegroups.com
Hello,
syzbot found the following crash on:
HEAD commit: 7fe05eed Merge 4.9.194 into android-4.9
git tree: android-4.9
console output: https://syzkaller.appspot.com/x/log.txt?x=12253f34e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=c6d462552c77f021
dashboard link: https://syzkaller.appspot.com/bug?extid=89caea70641cef1f152c
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
Unfortunately, I don't have any reproducer for this crash yet.
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+89caea...@syzkaller.appspotmail.com
INFO: task syz-executor.5:8185 blocked for more than 140 seconds.
Not tainted 4.9.194+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.5 D29144 8185 2097 0x80000002
0000000000000083 ffff8801cedc8000 ffff8801c8f47900 ffff8801db721000
ffff88019fd597c0 ffff8801db721018 ffff8801a0f576b8 ffffffff8281af8e
ffff8801cedc8000 ffff8801a0f57790 0000000000000046 ffff8801db7218f0
Call Trace:
[<00000000ead3efb9>] schedule+0x92/0x1c0 kernel/sched/core.c:3546
[<00000000b4ed1270>] schedule_preempt_disabled+0x13/0x20
kernel/sched/core.c:3579
[<000000009369b568>] __mutex_lock_common kernel/locking/mutex.c:582
[inline]
[<000000009369b568>] mutex_lock_nested+0x38d/0x920
kernel/locking/mutex.c:621
[<000000003dd10230>] lo_release+0x20/0x1b0 drivers/block/loop.c:1663
[<0000000043395d70>] __blkdev_put+0x461/0x840 fs/block_dev.c:1606
[<00000000eacd45e2>] blkdev_put+0x88/0x560 fs/block_dev.c:1671
[<00000000bf514b95>] blkdev_close+0x8b/0xb0 fs/block_dev.c:1678
[<000000001350ca8a>] __fput+0x274/0x720 fs/file_table.c:208
[<00000000379d2210>] ____fput+0x16/0x20 fs/file_table.c:244
[<00000000113ea1a3>] task_work_run+0x108/0x180 kernel/task_work.c:116
[<00000000864349a2>] exit_task_work include/linux/task_work.h:21 [inline]
[<00000000864349a2>] do_exit+0x78f/0x2aa0 kernel/exit.c:842
[<00000000dc8d7994>] do_group_exit+0x111/0x300 kernel/exit.c:946
[<00000000524ba93a>] get_signal+0x377/0x1cb0 kernel/signal.c:2395
[<0000000007874264>] do_signal+0x9c/0x1920 arch/x86/kernel/signal.c:812
[<00000000abe667f0>] exit_to_usermode_loop+0x11c/0x160
arch/x86/entry/common.c:159
[<000000000626a69d>] prepare_exit_to_usermode arch/x86/entry/common.c:195
[inline]
[<000000000626a69d>] syscall_return_slowpath arch/x86/entry/common.c:266
[inline]
[<000000000626a69d>] do_syscall_64+0x3ab/0x5c0 arch/x86/entry/common.c:293
[<00000000d4ae23ea>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Showing all locks held in the system:
2 locks held by khungtaskd/24:
#0: (rcu_read_lock){......}, at: [<000000004a2cd4c2>]
check_hung_uninterruptible_tasks kernel/hung_task.c:169 [inline]
#0: (rcu_read_lock){......}, at: [<000000004a2cd4c2>]
watchdog+0x14b/0xaf0 kernel/hung_task.c:263
#1: (tasklist_lock){.+.+..}, at: [<000000005120eb84>]
debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4336
2 locks held by getty/2028:
#0: (&tty->ldisc_sem){++++++}, at: [<00000000abe8c6ee>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.+.}, at: [<0000000090d29ad2>]
n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156
2 locks held by syz-executor.5/8185:
#0: (&bdev->bd_mutex){+.+.+.}, at: [<000000003eba0848>]
__blkdev_put+0xbb/0x840 fs/block_dev.c:1587
#1: (loop_index_mutex){+.+.+.}, at: [<000000003dd10230>]
lo_release+0x20/0x1b0 drivers/block/loop.c:1663
1 lock held by syz-executor.5/8387:
#0: (&bdev->bd_mutex){+.+.+.}, at: [<0000000067de4d26>]
blkdev_put+0x2b/0x560 fs/block_dev.c:1629
2 locks held by syz-executor.5/8748:
#0: (&bdev->bd_mutex){+.+.+.}, at: [<000000003eba0848>]
__blkdev_put+0xbb/0x840 fs/block_dev.c:1587
#1: (loop_index_mutex){+.+.+.}, at: [<000000003dd10230>]
lo_release+0x20/0x1b0 drivers/block/loop.c:1663
2 locks held by syz-executor.3/17511:
#0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000b6b27375>]
__blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273
#1: (loop_index_mutex){+.+.+.}, at: [<00000000adffec09>]
lo_open+0x1d/0xb0 drivers/block/loop.c:1621
2 locks held by syz-executor.0/17672:
#0: (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<00000000c37817c8>]
lo_ioctl+0x8e/0x1b10 drivers/block/loop.c:1404
#1: (&bdev->bd_mutex){+.+.+.}, at: [<000000006ccffc40>]
blkdev_reread_part+0x1f/0x40 block/ioctl.c:189
1 lock held by syz-executor.0/17723:
#0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000b6b27375>]
__blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273
1 lock held by syz-executor.4/17676:
#0: (loop_index_mutex){+.+.+.}, at: [<000000007da8a6d2>]
loop_control_ioctl+0x7a/0x320 drivers/block/loop.c:1973
1 lock held by syz-executor.4/17695:
#0: (loop_index_mutex){+.+.+.}, at: [<000000007da8a6d2>]
loop_control_ioctl+0x7a/0x320 drivers/block/loop.c:1973
1 lock held by syz-executor.4/17705:
#0: (loop_index_mutex){+.+.+.}, at: [<000000007da8a6d2>]
loop_control_ioctl+0x7a/0x320 drivers/block/loop.c:1973
1 lock held by syz-executor.4/17722:
#0: (loop_index_mutex){+.+.+.}, at: [<000000007da8a6d2>]
loop_control_ioctl+0x7a/0x320 drivers/block/loop.c:1973
2 locks held by syz-executor.5/17671:
#0: (loop_index_mutex){+.+.+.}, at: [<000000007da8a6d2>]
loop_control_ioctl+0x7a/0x320 drivers/block/loop.c:1973
#1: (&lo->lo_ctl_mutex#2){+.+.+.}, at: [<00000000e0f59c0c>]
loop_control_ioctl+0x17f/0x320 drivers/block/loop.c:1987
1 lock held by syz-executor.5/17690:
#0: (loop_index_mutex){+.+.+.}, at: [<000000007da8a6d2>]
loop_control_ioctl+0x7a/0x320 drivers/block/loop.c:1973
1 lock held by syz-executor.5/17703:
#0: (loop_index_mutex){+.+.+.}, at: [<000000007da8a6d2>]
loop_control_ioctl+0x7a/0x320 drivers/block/loop.c:1973
1 lock held by syz-executor.5/17721:
#0: (loop_index_mutex){+.+.+.}, at: [<000000007da8a6d2>]
loop_control_ioctl+0x7a/0x320 drivers/block/loop.c:1973
2 locks held by blkid/17681:
#0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000b6b27375>]
__blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273
#1: (loop_index_mutex){+.+.+.}, at: [<00000000adffec09>]
lo_open+0x1d/0xb0 drivers/block/loop.c:1621
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 24 Comm: khungtaskd Not tainted 4.9.194+ #0
ffff8801d98d7cc8 ffffffff81b67001 0000000000000000 0000000000000000
0000000000000000 ffffffff81099d01 dffffc0000000000 ffff8801d98d7d00
ffffffff81b7229c 0000000000000000 0000000000000000 0000000000000000
Call Trace:
[<000000007d3eb629>] __dump_stack lib/dump_stack.c:15 [inline]
[<000000007d3eb629>] dump_stack+0xc1/0x120 lib/dump_stack.c:51
[<00000000f2ef4162>] nmi_cpu_backtrace.cold+0x47/0x87
lib/nmi_backtrace.c:99
[<000000009cc1a074>] nmi_trigger_cpumask_backtrace+0x124/0x155
lib/nmi_backtrace.c:60
[<00000000bbaa2ba3>] arch_trigger_cpumask_backtrace+0x14/0x20
arch/x86/kernel/apic/hw_nmi.c:37
[<000000006fb8ca18>] trigger_all_cpu_backtrace include/linux/nmi.h:58
[inline]
[<000000006fb8ca18>] check_hung_task kernel/hung_task.c:126 [inline]
[<000000006fb8ca18>] check_hung_uninterruptible_tasks
kernel/hung_task.c:183 [inline]
[<000000006fb8ca18>] watchdog+0x670/0xaf0 kernel/hung_task.c:263
[<00000000a5b9ea80>] kthread+0x278/0x310 kernel/kthread.c:211
[<000000003a6e2e78>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:375
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff8282a0e1
---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot found the following crash on:
HEAD commit: 7fe05eed Merge 4.9.194 into android-4.9
git tree: android-4.9
console output: https://syzkaller.appspot.com/x/log.txt?x=12253f34e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=c6d462552c77f021
dashboard link: https://syzkaller.appspot.com/bug?extid=89caea70641cef1f152c
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
Unfortunately, I don't have any reproducer for this crash yet.
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+89caea...@syzkaller.appspotmail.com
INFO: task syz-executor.5:8185 blocked for more than 140 seconds.
Not tainted 4.9.194+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.5 D29144 8185 2097 0x80000002
0000000000000083 ffff8801cedc8000 ffff8801c8f47900 ffff8801db721000
ffff88019fd597c0 ffff8801db721018 ffff8801a0f576b8 ffffffff8281af8e
ffff8801cedc8000 ffff8801a0f57790 0000000000000046 ffff8801db7218f0
Call Trace:
[<00000000ead3efb9>] schedule+0x92/0x1c0 kernel/sched/core.c:3546
[<00000000b4ed1270>] schedule_preempt_disabled+0x13/0x20
kernel/sched/core.c:3579
[<000000009369b568>] __mutex_lock_common kernel/locking/mutex.c:582
[inline]
[<000000009369b568>] mutex_lock_nested+0x38d/0x920
kernel/locking/mutex.c:621
[<000000003dd10230>] lo_release+0x20/0x1b0 drivers/block/loop.c:1663
[<0000000043395d70>] __blkdev_put+0x461/0x840 fs/block_dev.c:1606
[<00000000eacd45e2>] blkdev_put+0x88/0x560 fs/block_dev.c:1671
[<00000000bf514b95>] blkdev_close+0x8b/0xb0 fs/block_dev.c:1678
[<000000001350ca8a>] __fput+0x274/0x720 fs/file_table.c:208
[<00000000379d2210>] ____fput+0x16/0x20 fs/file_table.c:244
[<00000000113ea1a3>] task_work_run+0x108/0x180 kernel/task_work.c:116
[<00000000864349a2>] exit_task_work include/linux/task_work.h:21 [inline]
[<00000000864349a2>] do_exit+0x78f/0x2aa0 kernel/exit.c:842
[<00000000dc8d7994>] do_group_exit+0x111/0x300 kernel/exit.c:946
[<00000000524ba93a>] get_signal+0x377/0x1cb0 kernel/signal.c:2395
[<0000000007874264>] do_signal+0x9c/0x1920 arch/x86/kernel/signal.c:812
[<00000000abe667f0>] exit_to_usermode_loop+0x11c/0x160
arch/x86/entry/common.c:159
[<000000000626a69d>] prepare_exit_to_usermode arch/x86/entry/common.c:195
[inline]
[<000000000626a69d>] syscall_return_slowpath arch/x86/entry/common.c:266
[inline]
[<000000000626a69d>] do_syscall_64+0x3ab/0x5c0 arch/x86/entry/common.c:293
[<00000000d4ae23ea>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Showing all locks held in the system:
2 locks held by khungtaskd/24:
#0: (rcu_read_lock){......}, at: [<000000004a2cd4c2>]
check_hung_uninterruptible_tasks kernel/hung_task.c:169 [inline]
#0: (rcu_read_lock){......}, at: [<000000004a2cd4c2>]
watchdog+0x14b/0xaf0 kernel/hung_task.c:263
#1: (tasklist_lock){.+.+..}, at: [<000000005120eb84>]
debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4336
2 locks held by getty/2028:
#0: (&tty->ldisc_sem){++++++}, at: [<00000000abe8c6ee>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.+.}, at: [<0000000090d29ad2>]
n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156
2 locks held by syz-executor.5/8185:
#0: (&bdev->bd_mutex){+.+.+.}, at: [<000000003eba0848>]
__blkdev_put+0xbb/0x840 fs/block_dev.c:1587
#1: (loop_index_mutex){+.+.+.}, at: [<000000003dd10230>]
lo_release+0x20/0x1b0 drivers/block/loop.c:1663
1 lock held by syz-executor.5/8387:
#0: (&bdev->bd_mutex){+.+.+.}, at: [<0000000067de4d26>]
blkdev_put+0x2b/0x560 fs/block_dev.c:1629
2 locks held by syz-executor.5/8748:
#0: (&bdev->bd_mutex){+.+.+.}, at: [<000000003eba0848>]
__blkdev_put+0xbb/0x840 fs/block_dev.c:1587
#1: (loop_index_mutex){+.+.+.}, at: [<000000003dd10230>]
lo_release+0x20/0x1b0 drivers/block/loop.c:1663
2 locks held by syz-executor.3/17511:
#0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000b6b27375>]
__blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273
#1: (loop_index_mutex){+.+.+.}, at: [<00000000adffec09>]
lo_open+0x1d/0xb0 drivers/block/loop.c:1621
2 locks held by syz-executor.0/17672:
#0: (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<00000000c37817c8>]
lo_ioctl+0x8e/0x1b10 drivers/block/loop.c:1404
#1: (&bdev->bd_mutex){+.+.+.}, at: [<000000006ccffc40>]
blkdev_reread_part+0x1f/0x40 block/ioctl.c:189
1 lock held by syz-executor.0/17723:
#0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000b6b27375>]
__blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273
1 lock held by syz-executor.4/17676:
#0: (loop_index_mutex){+.+.+.}, at: [<000000007da8a6d2>]
loop_control_ioctl+0x7a/0x320 drivers/block/loop.c:1973
1 lock held by syz-executor.4/17695:
#0: (loop_index_mutex){+.+.+.}, at: [<000000007da8a6d2>]
loop_control_ioctl+0x7a/0x320 drivers/block/loop.c:1973
1 lock held by syz-executor.4/17705:
#0: (loop_index_mutex){+.+.+.}, at: [<000000007da8a6d2>]
loop_control_ioctl+0x7a/0x320 drivers/block/loop.c:1973
1 lock held by syz-executor.4/17722:
#0: (loop_index_mutex){+.+.+.}, at: [<000000007da8a6d2>]
loop_control_ioctl+0x7a/0x320 drivers/block/loop.c:1973
2 locks held by syz-executor.5/17671:
#0: (loop_index_mutex){+.+.+.}, at: [<000000007da8a6d2>]
loop_control_ioctl+0x7a/0x320 drivers/block/loop.c:1973
#1: (&lo->lo_ctl_mutex#2){+.+.+.}, at: [<00000000e0f59c0c>]
loop_control_ioctl+0x17f/0x320 drivers/block/loop.c:1987
1 lock held by syz-executor.5/17690:
#0: (loop_index_mutex){+.+.+.}, at: [<000000007da8a6d2>]
loop_control_ioctl+0x7a/0x320 drivers/block/loop.c:1973
1 lock held by syz-executor.5/17703:
#0: (loop_index_mutex){+.+.+.}, at: [<000000007da8a6d2>]
loop_control_ioctl+0x7a/0x320 drivers/block/loop.c:1973
1 lock held by syz-executor.5/17721:
#0: (loop_index_mutex){+.+.+.}, at: [<000000007da8a6d2>]
loop_control_ioctl+0x7a/0x320 drivers/block/loop.c:1973
2 locks held by blkid/17681:
#0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000b6b27375>]
__blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273
#1: (loop_index_mutex){+.+.+.}, at: [<00000000adffec09>]
lo_open+0x1d/0xb0 drivers/block/loop.c:1621
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 24 Comm: khungtaskd Not tainted 4.9.194+ #0
ffff8801d98d7cc8 ffffffff81b67001 0000000000000000 0000000000000000
0000000000000000 ffffffff81099d01 dffffc0000000000 ffff8801d98d7d00
ffffffff81b7229c 0000000000000000 0000000000000000 0000000000000000
Call Trace:
[<000000007d3eb629>] __dump_stack lib/dump_stack.c:15 [inline]
[<000000007d3eb629>] dump_stack+0xc1/0x120 lib/dump_stack.c:51
[<00000000f2ef4162>] nmi_cpu_backtrace.cold+0x47/0x87
lib/nmi_backtrace.c:99
[<000000009cc1a074>] nmi_trigger_cpumask_backtrace+0x124/0x155
lib/nmi_backtrace.c:60
[<00000000bbaa2ba3>] arch_trigger_cpumask_backtrace+0x14/0x20
arch/x86/kernel/apic/hw_nmi.c:37
[<000000006fb8ca18>] trigger_all_cpu_backtrace include/linux/nmi.h:58
[inline]
[<000000006fb8ca18>] check_hung_task kernel/hung_task.c:126 [inline]
[<000000006fb8ca18>] check_hung_uninterruptible_tasks
kernel/hung_task.c:183 [inline]
[<000000006fb8ca18>] watchdog+0x670/0xaf0 kernel/hung_task.c:263
[<00000000a5b9ea80>] kthread+0x278/0x310 kernel/kthread.c:211
[<000000003a6e2e78>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:375
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff8282a0e1
---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot
Mar 16, 2020, 12:39:11 AM3/16/20
to syzkaller-a...@googlegroups.com
Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.
Crashes did not happen for a while, no reproducer and no activity.
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