syzbot


INFO: task hung in __blkdev_put

Status: auto-closed as invalid on 2019/07/30 23:46
Reported-by: syzbot+801ee1539e8742f79a4c@syzkaller.appspotmail.com
First crash: 1938d, last: 1938d
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-44 INFO: task hung in __blkdev_put 3 2218d 2221d 0/2 auto-closed as invalid on 2019/02/22 12:37
upstream INFO: task hung in __blkdev_put fs 3 2233d 2238d 0/26 auto-closed as invalid on 2019/02/22 10:34
android-49 INFO: task hung in __blkdev_put 3 2225d 2236d 0/3 auto-closed as invalid on 2019/02/22 15:29

Sample crash report:
INFO: task syz-executor0:9139 blocked for more than 140 seconds.
      Not tainted 4.14.96+ #20
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0   D25640  9139      1 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3490
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3548
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893
 __blkdev_put+0xb1/0x6d0 fs/block_dev.c:1778
 blkdev_close+0x86/0xb0 fs/block_dev.c:1863
 __fput+0x25e/0x700 fs/file_table.c:210
 task_work_run+0x118/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x13b/0x160 arch/x86/entry/common.c:163
 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:267 [inline]
 do_syscall_64+0x372/0x4b0 arch/x86/entry/common.c:294
INFO: task syz-executor3:11178 blocked for more than 140 seconds.
      Not tainted 4.14.96+ #20
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor3   D27224 11178   9189 0x80000002
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3490
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3548
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893
 lo_release+0x19/0x170 drivers/block/loop.c:1643
 __blkdev_put+0x518/0x6d0 fs/block_dev.c:1791
 blkdev_close+0x86/0xb0 fs/block_dev.c:1863
 __fput+0x25e/0x700 fs/file_table.c:210
 task_work_run+0x118/0x190 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x903/0x2760 kernel/exit.c:865
INFO: task blkid:14070 blocked for more than 140 seconds.
      Not tainted 4.14.96+ #20
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid           D28808 14070   2993 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3490
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3548
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893
 lo_release+0x19/0x170 drivers/block/loop.c:1643
 __blkdev_put+0x518/0x6d0 fs/block_dev.c:1791
 blkdev_close+0x86/0xb0 fs/block_dev.c:1863
 __fput+0x25e/0x700 fs/file_table.c:210
 task_work_run+0x118/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x13b/0x160 arch/x86/entry/common.c:163
 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:267 [inline]
 do_syscall_64+0x372/0x4b0 arch/x86/entry/common.c:294
INFO: task syz-executor3:14073 blocked for more than 140 seconds.
      Not tainted 4.14.96+ #20
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor3   D29192 14073   9189 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3490
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3548
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893
 blkdev_reread_part+0x1b/0x40 block/ioctl.c:192
 loop_reread_partitions+0x72/0x80 drivers/block/loop.c:614
 loop_set_status+0xbff/0x11f0 drivers/block/loop.c:1183
INFO: task syz-executor3:14080 blocked for more than 140 seconds.
      Not tainted 4.14.96+ #20
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor3   D29152 14080   9189 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3490
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3548
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893
 __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457
 blkdev_get+0x97/0x8b0 fs/block_dev.c:1612
 blkdev_open+0x1cc/0x250 fs/block_dev.c:1770
 do_dentry_open+0x41b/0xd60 fs/open.c:764
 vfs_open+0x105/0x230 fs/open.c:878
 do_last fs/namei.c:3455 [inline]
 path_openat+0xb6b/0x2b70 fs/namei.c:3597
 do_filp_open+0x1a1/0x280 fs/namei.c:3631
 do_sys_open+0x2ca/0x590 fs/open.c:1071
 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289

Showing all locks held in the system:
1 lock held by khungtaskd/23:
 #0:  (tasklist_lock){.+.+}, at: [<ffffffffa3fffeec>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4541
2 locks held by getty/1767:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffffa4b36f02>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:275
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffffa4b32327>] n_tty_read+0x1f7/0x1700 drivers/tty/n_tty.c:2156
1 lock held by syz-executor0/9139:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffffa4415361>] __blkdev_put+0xb1/0x6d0 fs/block_dev.c:1778
2 locks held by syz-executor3/11178:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffffa4415361>] __blkdev_put+0xb1/0x6d0 fs/block_dev.c:1778
 #1:  (loop_ctl_mutex){+.+.}, at: [<ffffffffa4be8669>] lo_release+0x19/0x170 drivers/block/loop.c:1643
2 locks held by blkid/14070:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffffa4415361>] __blkdev_put+0xb1/0x6d0 fs/block_dev.c:1778
 #1:  (loop_ctl_mutex){+.+.}, at: [<ffffffffa4be8669>] lo_release+0x19/0x170 drivers/block/loop.c:1643
2 locks held by syz-executor3/14073:
 #0:  (loop_ctl_mutex/1){+.+.}, at: [<ffffffffa4be6c33>] lo_ioctl+0x83/0x1970 drivers/block/loop.c:1404
 #1:  (&bdev->bd_mutex){+.+.}, at: [<ffffffffa4919d3b>] blkdev_reread_part+0x1b/0x40 block/ioctl.c:192
1 lock held by syz-executor3/14080:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffffa4415a73>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457

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

NMI backtrace for cpu 1
CPU: 1 PID: 23 Comm: khungtaskd Not tainted 4.14.96+ #20
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0xb9/0x10e lib/dump_stack.c:53
 nmi_cpu_backtrace.cold+0x47/0x86 lib/nmi_backtrace.c:101
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at pc 0xffffffffa5650692

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/01/31 23:45 android-4.14 63d1657d00e0 0e8ea0a3 .config console log report ci-android-414-kasan-gce-root
* Struck through repros no longer work on HEAD.