syzbot


INFO: task hung in __blkdev_put
Status: auto-closed as invalid on 2019/02/22 10:34
Reported-by: syzbot+feea3dc291bb64479250@syzkaller.appspotmail.com
First crash: 1512d, last: 1507d
similar bugs (3):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-44 INFO: task hung in __blkdev_put 3 1491d 1494d 0/2 auto-closed as invalid on 2019/02/22 12:37
android-414 INFO: task hung in __blkdev_put 1 1211d 1138d 0/1 auto-closed as invalid on 2019/07/30 23:46
android-49 INFO: task hung in __blkdev_put 3 1498d 1509d 0/3 auto-closed as invalid on 2019/02/22 15:29

Sample crash report:
unregister_netdevice: waiting for lo to become free. Usage count = 1
unregister_netdevice: waiting for lo to become free. Usage count = 1
unregister_netdevice: waiting for lo to become free. Usage count = 1
unregister_netdevice: waiting for lo to become free. Usage count = 1
unregister_netdevice: waiting for lo to become free. Usage count = 1
INFO: task syz-executor5:10094 blocked for more than 120 seconds.
      Not tainted 4.16.0+ #18
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor5   D18624 10094   4541 0x80000006
Call Trace:
 context_switch kernel/sched/core.c:2848 [inline]
 __schedule+0x807/0x1e40 kernel/sched/core.c:3490
 schedule+0xef/0x430 kernel/sched/core.c:3549
 io_schedule+0x1c/0x70 kernel/sched/core.c:5169
 wait_on_page_bit_common+0x4dc/0x770 mm/filemap.c:1099
 wait_on_page_bit mm/filemap.c:1132 [inline]
 wait_on_page_writeback include/linux/pagemap.h:546 [inline]
 __filemap_fdatawait_range+0x31e/0x4c0 mm/filemap.c:533
 filemap_fdatawait_range mm/filemap.c:558 [inline]
 filemap_fdatawait include/linux/fs.h:2594 [inline]
 filemap_write_and_wait+0x93/0x100 mm/filemap.c:624
 __sync_blockdev fs/block_dev.c:448 [inline]
 sync_blockdev fs/block_dev.c:457 [inline]
 __blkdev_put+0x202/0x830 fs/block_dev.c:1783
 blkdev_put+0x98/0x540 fs/block_dev.c:1852
 blkdev_close+0x8b/0xb0 fs/block_dev.c:1859
 __fput+0x34d/0x890 fs/file_table.c:209
 ____fput+0x15/0x20 fs/file_table.c:243
 task_work_run+0x1e4/0x290 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x1aee/0x2730 kernel/exit.c:865
 do_group_exit+0x16f/0x430 kernel/exit.c:968
 get_signal+0x886/0x1960 kernel/signal.c:2469
 do_signal+0x98/0x2040 arch/x86/kernel/signal.c:810
 exit_to_usermode_loop+0x28a/0x310 arch/x86/entry/common.c:162
 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:265 [inline]
 do_syscall_64+0x792/0x9d0 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x455259
RSP: 002b:00007f6e7133fc68 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: 0000000000041000 RBX: 00007f6e713406d4 RCX: 0000000000455259
RDX: 00000000200ddff8 RSI: 0000000000000014 RDI: 0000000000000013
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000102000001 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000004c6 R14: 00000000006fa330 R15: 0000000000000000

Showing all locks held in the system:
4 locks held by kworker/u4:3/71:
 #0: 00000000e30c6b31 ((wq_completion)"%s""netns"){+.+.}, at: __write_once_size include/linux/compiler.h:215 [inline]
 #0: 00000000e30c6b31 ((wq_completion)"%s""netns"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: 00000000e30c6b31 ((wq_completion)"%s""netns"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline]
 #0: 00000000e30c6b31 ((wq_completion)"%s""netns"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:57 [inline]
 #0: 00000000e30c6b31 ((wq_completion)"%s""netns"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline]
 #0: 00000000e30c6b31 ((wq_completion)"%s""netns"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0: 00000000e30c6b31 ((wq_completion)"%s""netns"){+.+.}, at: process_one_work+0xaef/0x1b50 kernel/workqueue.c:2116
 #1: 00000000b624f1e0 (net_cleanup_work){+.+.}, at: process_one_work+0xb46/0x1b50 kernel/workqueue.c:2120
 #2: 000000001c182a13 (pernet_ops_rwsem){++++}, at: cleanup_net+0x11a/0xb20 net/core/net_namespace.c:490
 #3: 0000000020d5a264 (rcu_sched_state.barrier_mutex){+.+.}, at: _rcu_barrier+0x142/0x770 kernel/rcu/tree.c:3495
2 locks held by khungtaskd/889:
 #0: 00000000017a2a34 (rcu_read_lock){....}, at: check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline]
 #0: 00000000017a2a34 (rcu_read_lock){....}, at: watchdog+0x1ff/0xf60 kernel/hung_task.c:249
 #1: 00000000340d4b67 (tasklist_lock){.+.+}, at: debug_show_all_locks+0xde/0x34a kernel/locking/lockdep.c:4470
2 locks held by login/4460:
 #0: 0000000025923d0a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 000000004bfa20d6 (&tty->atomic_write_lock){+.+.}, at: tty_write_lock+0x23/0x90 drivers/tty/tty_io.c:884
2 locks held by getty/4461:
 #0: 0000000063b30623 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 00000000d6a83dfe (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by getty/4462:
 #0: 00000000bb99d742 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 00000000244cab96 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by getty/4463:
 #0: 0000000073ea9ef1 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 000000001dec2112 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by getty/4464:
 #0: 00000000966d3b42 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 0000000097296c12 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by getty/4465:
 #0: 00000000195663a0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 0000000006c76394 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by getty/4466:
 #0: 00000000ea1f068e (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 00000000215b9c88 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
3 locks held by kworker/u4:6/16200:
 #0: 0000000095be5a30 ((wq_completion)"writeback"){+.+.}, at: __write_once_size include/linux/compiler.h:215 [inline]
 #0: 0000000095be5a30 ((wq_completion)"writeback"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: 0000000095be5a30 ((wq_completion)"writeback"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline]
 #0: 0000000095be5a30 ((wq_completion)"writeback"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:57 [inline]
 #0: 0000000095be5a30 ((wq_completion)"writeback"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline]
 #0: 0000000095be5a30 ((wq_completion)"writeback"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0: 0000000095be5a30 ((wq_completion)"writeback"){+.+.}, at: process_one_work+0xaef/0x1b50 kernel/workqueue.c:2116
 #1: 000000008a53b474 ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0xb46/0x1b50 kernel/workqueue.c:2120
 #2: 000000008638ed65 (&type->s_umount_key#35){++++}, at: trylock_super+0x22/0x110 fs/super.c:395
1 lock held by syz-executor5/10094:
 #0: 00000000fc9356c0 (&bdev->bd_mutex){+.+.}, at: __blkdev_put+0xc2/0x830 fs/block_dev.c:1777
1 lock held by blkid/10139:
 #0: 00000000fc9356c0 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x193/0x13a0 fs/block_dev.c:1460

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

NMI backtrace for cpu 1
CPU: 1 PID: 889 Comm: khungtaskd Not tainted 4.16.0+ #18
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+0x1b9/0x294 lib/dump_stack.c:113
 nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103
 nmi_trigger_cpumask_backtrace+0x151/0x192 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+0xc10/0xf60 kernel/hung_task.c:249
 kthread+0x345/0x410 kernel/kthread.c:238
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:411
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54

Crashes (3):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce 2018/04/11 05:40 upstream c18bb396d3d2 8b8de427 .config log report
ci-upstream-kasan-gce 2018/04/10 14:53 upstream c18bb396d3d2 8e873e9d .config log report
ci-upstream-kasan-gce 2018/04/06 05:16 upstream e02d37bf55a9 a932eae6 .config log report