loop1: p252 start 1854537728 is beyond EOD, truncated loop1: p253 start 1854537728 is beyond EOD, truncated loop1: p254 start 1854537728 is beyond EOD, truncated loop1: p255 start 1854537728 is beyond EOD, truncated INFO: task syz-executor.2:820 blocked for more than 140 seconds. Not tainted 4.9.203-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D25544 820 819 0x00000000 0000000000000083 ffff8801d7a897c0 ffff8801ca1c7900 ffff8801db71ffc0 ffff8801b823af80 ffff8801db71ffd8 ffff8801c82af688 ffffffff8280a79e 0000000041b58ab3 ffffffff82e2adf8 00ffffff81205320 ffff8801db7208b0 Call Trace: [<00000000a4d6d2bd>] schedule+0x92/0x1c0 kernel/sched/core.c:3546 [<0000000079a5b32b>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3579 [<0000000039fc37ba>] __mutex_lock_common kernel/locking/mutex.c:582 [inline] [<0000000039fc37ba>] mutex_lock_nested+0x38d/0x920 kernel/locking/mutex.c:621 [<0000000032713353>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 [<0000000000dcf57b>] __blkdev_get+0x268/0xeb0 fs/block_dev.c:1287 [<0000000047246706>] blkdev_get+0x2e8/0x920 fs/block_dev.c:1424 [<00000000c34d0070>] blkdev_open+0x1aa/0x250 fs/block_dev.c:1579 [<00000000747dc8ee>] do_dentry_open+0x422/0xd20 fs/open.c:791 [<000000006152dfe9>] vfs_open+0x105/0x230 fs/open.c:904 [<00000000f29e30d3>] do_last fs/namei.c:3457 [inline] [<00000000f29e30d3>] path_openat+0xbf5/0x2f60 fs/namei.c:3581 [<00000000ad87f211>] do_filp_open+0x1a1/0x280 fs/namei.c:3615 [<0000000037a91c3e>] do_sys_open+0x2f0/0x610 fs/open.c:1097 [<000000007cb6358c>] SYSC_open fs/open.c:1115 [inline] [<000000007cb6358c>] SyS_open+0x2d/0x40 fs/open.c:1110 [<00000000c02958ad>] do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288 [<00000000a43bc9f4>] 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: [<00000000789a0ce3>] check_hung_uninterruptible_tasks kernel/hung_task.c:169 [inline] #0: (rcu_read_lock){......}, at: [<00000000789a0ce3>] watchdog+0x14b/0xaf0 kernel/hung_task.c:263 #1: (tasklist_lock){.+.+..}, at: [<000000008e744588>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4339 1 lock held by rsyslogd/1899: #0: (&f->f_pos_lock){+.+.+.}, at: [<000000009b4c0354>] __fdget_pos+0xa8/0xd0 fs/file.c:782 2 locks held by getty/2027: #0: (&tty->ldisc_sem){++++++}, at: [<000000000adffab5>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.+.}, at: [<00000000366357bd>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.2/820: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000d940f63d>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<0000000032713353>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 2 locks held by syz-executor.1/7145: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000efd46eb6>] __blkdev_put+0xbb/0x840 fs/block_dev.c:1587 #1: (loop_index_mutex){+.+.+.}, at: [<000000004f36adeb>] lo_release+0x20/0x1b0 drivers/block/loop.c:1664 1 lock held by blkid/7153: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000d9efc22b>] blkdev_put+0x2b/0x560 fs/block_dev.c:1629 2 locks held by syz-executor.0/7181: #0: (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<0000000052fd8230>] lo_ioctl+0x8e/0x1b10 drivers/block/loop.c:1404 #1: (&bdev->bd_mutex){+.+.+.}, at: [<000000002b94bf5e>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:189 2 locks held by syz-executor.3/7199: #0: (loop_index_mutex){+.+.+.}, at: [<00000000ef34935c>] loop_control_ioctl+0x7a/0x320 drivers/block/loop.c:1974 #1: (&lo->lo_ctl_mutex#2){+.+.+.}, at: [<00000000b1f284b4>] loop_control_ioctl+0x17f/0x320 drivers/block/loop.c:1988 2 locks held by blkid/7201: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000d940f63d>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<0000000032713353>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 24 Comm: khungtaskd Not tainted 4.9.203-syzkaller #0 ffff8801d98d7cc8 ffffffff81b55f6b 0000000000000000 0000000000000000 0000000000000000 ffffffff8109a001 dffffc0000000000 ffff8801d98d7d00 ffffffff81b6120c 0000000000000000 0000000000000000 0000000000000000 Call Trace: [<00000000785e754c>] __dump_stack lib/dump_stack.c:15 [inline] [<00000000785e754c>] dump_stack+0xcb/0x130 lib/dump_stack.c:56 [<00000000274ef6e9>] nmi_cpu_backtrace.cold+0x47/0x87 lib/nmi_backtrace.c:99 [<00000000738ac67b>] nmi_trigger_cpumask_backtrace+0x124/0x155 lib/nmi_backtrace.c:60 [<0000000014454614>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 [<00000000befae2c6>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline] [<00000000befae2c6>] check_hung_task kernel/hung_task.c:126 [inline] [<00000000befae2c6>] check_hung_uninterruptible_tasks kernel/hung_task.c:183 [inline] [<00000000befae2c6>] watchdog+0x670/0xaf0 kernel/hung_task.c:263 [<00000000b3c9af77>] kthread+0x278/0x310 kernel/kthread.c:211 [<000000008d35b407>] 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 0xffffffff828198f1