syzbot


INFO: task hung in loop_control_ioctl

Status: public: reported C repro on 2019/04/12 00:00
Reported-by: syzbot+49e44e441be708902a76@syzkaller.appspotmail.com
First crash: 2561d, last: 1837d
Similar bugs (5)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in loop_control_ioctl block 4 2248d 2442d 11/28 fixed on 2019/01/15 20:25
android-414 INFO: task hung in loop_control_ioctl C 23 1868d 2065d 0/1 public: reported C repro on 2019/04/13 00:01
linux-4.14 INFO: task hung in loop_control_ioctl (2) C inconclusive 7 821d 1742d 0/1 upstream: reported C repro on 2020/02/29 17:00
android-44 INFO: task hung in loop_control_ioctl 6 2409d 2533d 0/2 auto-closed as invalid on 2019/02/22 15:22
linux-4.14 INFO: task hung in loop_control_ioctl 1 1899d 1899d 0/1 auto-closed as invalid on 2020/01/24 04:19

Sample crash report:
INFO: task syz-executor385:3867 blocked for more than 120 seconds.
      Not tainted 4.9.109-ge1815b3 #49
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor385 D29768  3867   3866 0x00000000
 ffff8801d76f6000 ffff8801c720ea00 ffff8801d98f3480 ffff8801d75fb000
 ffff8801db321c18 ffff8801d6d5fb48 ffffffff839e8a8d ffff8801d76f68c8
 ffffed003aeded18 ffff8801d76f6000 00fffc0000000000 ffff8801db3224e8
Call Trace:
 [<ffffffff839ea08f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3557
 [<ffffffff839eaa13>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3590
 [<ffffffff839eee96>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff839eee96>] mutex_lock_nested+0x326/0x870 kernel/locking/mutex.c:621
 [<ffffffff825cce5a>] loop_control_ioctl+0x7a/0x300 drivers/block/loop.c:1906
 [<ffffffff815b2b9c>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff815b2b9c>] file_ioctl fs/ioctl.c:493 [inline]
 [<ffffffff815b2b9c>] do_vfs_ioctl+0x1ac/0x11a0 fs/ioctl.c:677
 [<ffffffff815b3c1f>] SYSC_ioctl fs/ioctl.c:694 [inline]
 [<ffffffff815b3c1f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f9993>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:
2 locks held by khungtaskd/520:
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136662c>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136662c>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81425cb7>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/3772:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839f7b32>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff8211fce2>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2133
1 lock held by syz-executor385/3867:
 #0:  (loop_index_mutex){+.+.+.}, at: [<ffffffff825cce5a>] loop_control_ioctl+0x7a/0x300 drivers/block/loop.c:1906
1 lock held by syz-executor385/3868:
 #0:  (loop_index_mutex){+.+.+.}, at: [<ffffffff825cce5a>] loop_control_ioctl+0x7a/0x300 drivers/block/loop.c:1906
2 locks held by syz-executor385/3869:
 #0:  (loop_index_mutex){+.+.+.}, at: [<ffffffff825cce5a>] loop_control_ioctl+0x7a/0x300 drivers/block/loop.c:1906
 #1:  (&lo->lo_ctl_mutex#2){+.+...}, at: [<ffffffff825ccf66>] loop_control_ioctl+0x186/0x300 drivers/block/loop.c:1920
2 locks held by syz-executor385/3870:
 #0:  (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<ffffffff825ca87b>] lo_ioctl+0x8b/0x1aa0 drivers/block/loop.c:1344
 #1:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff81e564ae>] blkdev_reread_part+0x1e/0x40 block/ioctl.c:189
1 lock held by syz-executor385/3871:
 #0:  (loop_index_mutex){+.+.+.}, at: [<ffffffff825cce5a>] loop_control_ioctl+0x7a/0x300 drivers/block/loop.c:1906
2 locks held by syz-executor385/3872:
 #0:  (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<ffffffff825ca87b>] lo_ioctl+0x8b/0x1aa0 drivers/block/loop.c:1344
 #1:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff81e564ae>] blkdev_reread_part+0x1e/0x40 block/ioctl.c:189
2 locks held by syz-executor385/3873:
 #0:  (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<ffffffff825ca87b>] lo_ioctl+0x8b/0x1aa0 drivers/block/loop.c:1344
 #1:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff81e564ae>] blkdev_reread_part+0x1e/0x40 block/ioctl.c:189
1 lock held by syz-executor385/3874:
 #0:  (loop_index_mutex){+.+.+.}, at: [<ffffffff825cce5a>] loop_control_ioctl+0x7a/0x300 drivers/block/loop.c:1906
2 locks held by blkid/3876:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff8163129c>] __blkdev_get+0x10c/0xd60 fs/block_dev.c:1268
 #1:  (loop_index_mutex){+.+.+.}, at: [<ffffffff825c591b>] lo_open+0x1b/0xa0 drivers/block/loop.c:1555
2 locks held by blkid/3878:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff8163129c>] __blkdev_get+0x10c/0xd60 fs/block_dev.c:1268
 #1:  (loop_index_mutex){+.+.+.}, at: [<ffffffff825c591b>] lo_open+0x1b/0xa0 drivers/block/loop.c:1555
2 locks held by blkid/3883:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff8163129c>] __blkdev_get+0x10c/0xd60 fs/block_dev.c:1268
 #1:  (loop_index_mutex){+.+.+.}, at: [<ffffffff825c591b>] lo_open+0x1b/0xa0 drivers/block/loop.c:1555

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

NMI backtrace for cpu 1
CPU: 1 PID: 520 Comm: khungtaskd Not tainted 4.9.109-ge1815b3 #49
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d92dfd08 ffffffff81eb3e29 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810b9580 ffff8801d92dfd40
 ffffffff81ebf127 0000000000000001 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81eb3e29>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb3e29>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ebf127>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ebf0ba>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
 [<ffffffff810b9684>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81366bc4>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81366bc4>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81366bc4>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81366bc4>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119d04d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839f9b5c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff839f8596

Crashes (59):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/06/19 15:38 https://android.googlesource.com/kernel/common android-4.9 e1815b3eba5b 732e4256 .config console log report syz C ci-android-49-kasan-gce-root
2019/11/27 09:33 android-4.9 13ff5130ff6e 1048481f .config console log report ci-android-49-kasan-gce-root
2019/10/31 05:36 https://android.googlesource.com/kernel/common android-4.9 7fe05eede1c8 a41ca8fa .config console log report ci-android-49-kasan-gce-root
2019/10/22 14:05 https://android.googlesource.com/kernel/common android-4.9 7fe05eede1c8 c59a7cd8 .config console log report ci-android-49-kasan-gce-root
2019/10/20 05:47 https://android.googlesource.com/kernel/common android-4.9 7fe05eede1c8 8c88c9c1 .config console log report ci-android-49-kasan-gce-root
2019/10/19 19:06 https://android.googlesource.com/kernel/common android-4.9 7fe05eede1c8 8c88c9c1 .config console log report ci-android-49-kasan-gce-root
2018/12/06 12:16 https://android.googlesource.com/kernel/common android-4.9 e16c0406470a 3ab38479 .config console log report ci-android-49-kasan-gce-root
2018/10/18 11:22 https://android.googlesource.com/kernel/common android-4.9 3917c4a8adcc d257b2d2 .config console log report ci-android-49-kasan-gce-root
2018/09/09 13:13 https://android.googlesource.com/kernel/common android-4.9 dcae9fa1319b 6b5120a4 .config console log report ci-android-49-kasan-gce-root
2018/08/10 20:46 https://android.googlesource.com/kernel/common android-4.9 9dc978d43ec7 1fb62d58 .config console log report ci-android-49-kasan-gce
2018/06/04 14:12 https://android.googlesource.com/kernel/common android-4.9 d7e64f8022e4 6cbe7c26 .config console log report ci-android-49-kasan-gce-root
2018/06/01 00:40 https://android.googlesource.com/kernel/common android-4.9 a56900fabe12 2f93b54f .config console log report ci-android-49-kasan-gce-root
2018/05/11 14:38 https://android.googlesource.com/kernel/common android-4.9 c462abbf779b 12c7428a .config console log report ci-android-49-kasan-gce-root
2018/05/11 11:42 https://android.googlesource.com/kernel/common android-4.9 c462abbf779b 12c7428a .config console log report ci-android-49-kasan-gce-root
2018/05/09 23:16 https://android.googlesource.com/kernel/common android-4.9 c462abbf779b 12c7428a .config console log report ci-android-49-kasan-gce-root
2018/05/09 08:23 https://android.googlesource.com/kernel/common android-4.9 9731a2dab47e 12c7428a .config console log report ci-android-49-kasan-gce-root
2018/05/04 23:39 https://android.googlesource.com/kernel/common android-4.9 f5a861c30cb7 9ce14f4b .config console log report ci-android-49-kasan-gce-root
2018/05/04 07:21 https://android.googlesource.com/kernel/common android-4.9 0e25e2cab07a 9ce14f4b .config console log report ci-android-49-kasan-gce-root
2018/05/04 00:35 https://android.googlesource.com/kernel/common android-4.9 0e25e2cab07a 9ce14f4b .config console log report ci-android-49-kasan-gce-root
2018/04/30 15:55 https://android.googlesource.com/kernel/common android-4.9 2bcbbd5b3924 06db3cec .config console log report ci-android-49-kasan-gce-root
2018/04/30 14:05 https://android.googlesource.com/kernel/common android-4.9 2bcbbd5b3924 06db3cec .config console log report ci-android-49-kasan-gce-root
2018/04/30 14:03 https://android.googlesource.com/kernel/common android-4.9 2bcbbd5b3924 06db3cec .config console log report ci-android-49-kasan-gce-root
2018/04/28 02:09 https://android.googlesource.com/kernel/common android-4.9 71fce1edd26d d5a5d045 .config console log report ci-android-49-kasan-gce-root
2018/04/26 12:28 https://android.googlesource.com/kernel/common android-4.9 132f097f6547 73417389 .config console log report ci-android-49-kasan-gce-root
2018/04/26 05:00 https://android.googlesource.com/kernel/common android-4.9 8c01d009ed72 73417389 .config console log report ci-android-49-kasan-gce-root
2018/04/05 08:49 https://android.googlesource.com/kernel/common android-4.9 13b40d327b49 676bd07e .config console log report ci-android-49-kasan-gce
2018/03/06 02:08 https://android.googlesource.com/kernel/common android-4.9 b324a701539e aef0b792 .config console log report ci-android-49-kasan-gce
2018/02/07 07:20 https://android.googlesource.com/kernel/common android-4.9 550c01d0e051 66c15deb .config console log report ci-android-49-kasan-gce
2018/02/06 19:21 https://android.googlesource.com/kernel/common android-4.9 550c01d0e051 66c15deb .config console log report ci-android-49-kasan-gce
2017/12/18 07:23 https://android.googlesource.com/kernel/common android-4.9 3f1d77ca5f8f d5beb42a .config console log report ci-android-49-kasan-gce
2017/12/15 18:21 https://android.googlesource.com/kernel/common android-4.9 3f1d77ca5f8f ac20b98c .config console log report ci-android-49-kasan-gce
2017/12/12 15:08 https://android.googlesource.com/kernel/common android-4.9 fb66dc2a6e5e 414a185f .config console log report ci-android-49-kasan-gce
2017/12/11 15:57 https://android.googlesource.com/kernel/common android-4.9 f26d3c76d376 27f5dfef .config console log report ci-android-49-kasan-gce
2017/12/11 00:16 https://android.googlesource.com/kernel/common android-4.9 f26d3c76d376 5ad0ce95 .config console log report ci-android-49-kasan-gce
2017/12/11 00:05 https://android.googlesource.com/kernel/common android-4.9 f26d3c76d376 5ad0ce95 .config console log report ci-android-49-kasan-gce
2017/12/10 18:23 https://android.googlesource.com/kernel/common android-4.9 f26d3c76d376 5ad0ce95 .config console log report ci-android-49-kasan-gce
2017/12/10 02:22 https://android.googlesource.com/kernel/common android-4.9 f26d3c76d376 5ad0ce95 .config console log report ci-android-49-kasan-gce
2017/12/07 18:30 https://android.googlesource.com/kernel/common android-4.9 f26d3c76d376 5d643f8e .config console log report ci-android-49-kasan-gce
2017/12/07 09:52 https://android.googlesource.com/kernel/common android-4.9 f26d3c76d376 5d643f8e .config console log report ci-android-49-kasan-gce
2017/12/06 22:06 https://android.googlesource.com/kernel/common android-4.9 f26d3c76d376 5d643f8e .config console log report ci-android-49-kasan-gce
2017/12/06 05:27 https://android.googlesource.com/kernel/common android-4.9 f26d3c76d376 0796857b .config console log report ci-android-49-kasan-gce
2017/12/06 02:05 https://android.googlesource.com/kernel/common android-4.9 12cae95a096c de212f1a .config console log report ci-android-49-kasan-gce
2017/12/05 23:07 https://android.googlesource.com/kernel/common android-4.9 12cae95a096c de212f1a .config console log report ci-android-49-kasan-gce
2017/12/05 22:14 https://android.googlesource.com/kernel/common android-4.9 12cae95a096c de212f1a .config console log report ci-android-49-kasan-gce
2017/12/05 09:16 https://android.googlesource.com/kernel/common android-4.9 87cdf4eda5c7 de212f1a .config console log report ci-android-49-kasan-gce
2017/12/05 07:51 https://android.googlesource.com/kernel/common android-4.9 87cdf4eda5c7 de212f1a .config console log report ci-android-49-kasan-gce
2017/12/05 07:01 https://android.googlesource.com/kernel/common android-4.9 87cdf4eda5c7 de212f1a .config console log report ci-android-49-kasan-gce
2019/02/06 19:31 https://android.googlesource.com/kernel/common android-4.9 8fe428403e30 d25487bc .config console log report ci-android-49-kasan-gce-386
2018/03/21 00:22 https://android.googlesource.com/kernel/common android-4.9 71df7bbae4d8 113a43ff .config console log report ci-android-49-kasan-gce-386
* Struck through repros no longer work on HEAD.