audit: type=1400 audit(1555310166.948:5): avc: denied { associate } for pid=2561 comm="syz-executor.2" name="syz2" scontext=unconfined_u:object_r:unlabeled_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=filesystem permissive=1 INFO: task syz-executor.3:2562 blocked for more than 140 seconds. Not tainted 4.9.168+ #40 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D25064 2562 1 0x00000004 ffff8801c6925f00 0000000000000000 ffff8801db721000 ffff8801da6b2f80 ffff8801db721018 ffff8801c6587688 ffffffff8280028e ffff8801c6925f00 ffffffff841f18c0 00ff8801c65875e8 ffff8801db7218f0 1ffff10038cb0ec0 Call Trace: [<00000000163a8279>] schedule+0x92/0x1c0 kernel/sched/core.c:3546 [<000000006d5f35e0>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3579 [<000000004f053b42>] __mutex_lock_common kernel/locking/mutex.c:582 [inline] [<000000004f053b42>] mutex_lock_nested+0x38d/0x920 kernel/locking/mutex.c:621 [<00000000da4cb4f1>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 [<00000000d7962754>] __blkdev_get+0x268/0xeb0 fs/block_dev.c:1287 [<00000000dee2284f>] blkdev_get+0x2e8/0x920 fs/block_dev.c:1424 [<00000000da953169>] blkdev_open+0x1aa/0x250 fs/block_dev.c:1579 [<00000000dfa8662e>] do_dentry_open+0x422/0xd20 fs/open.c:772 [<00000000abed97fa>] vfs_open+0x105/0x230 fs/open.c:885 [<000000008fb9d267>] do_last fs/namei.c:3457 [inline] [<000000008fb9d267>] path_openat+0xbf5/0x2f60 fs/namei.c:3581 [<00000000acb1029b>] do_filp_open+0x1a1/0x280 fs/namei.c:3615 [<00000000fd375fbe>] do_sys_open+0x2f0/0x610 fs/open.c:1078 [<00000000e04079c3>] SYSC_open fs/open.c:1096 [inline] [<00000000e04079c3>] SyS_open+0x2d/0x40 fs/open.c:1091 [<00000000dd3b2d6f>] do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285 [<0000000095dd988c>] 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: [<000000004c24ecce>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline] #0: (rcu_read_lock){......}, at: [<000000004c24ecce>] watchdog+0x13c/0xae0 kernel/hung_task.c:239 #1: (tasklist_lock){.+.+..}, at: [<00000000ff72bb46>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4339 2 locks held by getty/2024: #0: (&tty->ldisc_sem){++++++}, at: [<0000000089846e3e>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377 #1: (&ldata->atomic_read_lock){+.+...}, at: [<0000000015499139>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.3/2562: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000a4213bfe>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<00000000da4cb4f1>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 3 locks held by syz-executor.5/2568: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000a8883252>] __blkdev_put+0xbb/0x840 fs/block_dev.c:1587 #1: (loop_index_mutex){+.+.+.}, at: [<00000000835cc924>] lo_release+0x1e/0x1b0 drivers/block/loop.c:1664 #2: (loop_ctl_mutex#2){+.+.+.}, at: [<000000007064606c>] __lo_release drivers/block/loop.c:1642 [inline] #2: (loop_ctl_mutex#2){+.+.+.}, at: [<000000007064606c>] lo_release+0x84/0x1b0 drivers/block/loop.c:1665 2 locks held by syz-executor.1/2571: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000a4213bfe>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<00000000da4cb4f1>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 2 locks held by syz-executor.4/3463: #0: (loop_ctl_mutex/1){+.+.+.}, at: [<000000000f4956ef>] lo_ioctl+0x85/0x1a10 drivers/block/loop.c:1405 #1: (&bdev->bd_mutex){+.+.+.}, at: [<00000000ad627b09>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:189 2 locks held by blkid/3464: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000a4213bfe>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<00000000da4cb4f1>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 1 lock held by blkid/3465: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000a4213bfe>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 2 locks held by syz-executor.2/3468: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000a4213bfe>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<00000000da4cb4f1>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 1 lock held by syz-executor.0/3469: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000a4213bfe>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 1 lock held by blkid/3475: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000a4213bfe>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 2 locks held by blkid/3477: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000a4213bfe>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<00000000da4cb4f1>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 24 Comm: khungtaskd Not tainted 4.9.168+ #40 ffff8801d98d7cc8 ffffffff81b4f5d1 0000000000000001 0000000000000000 0000000000000001 ffffffff81097401 dffffc0000000000 ffff8801d98d7d00 ffffffff81b5a86c 0000000000000001 0000000000000000 0000000000000001 Call Trace: [<0000000080f03fd8>] __dump_stack lib/dump_stack.c:15 [inline] [<0000000080f03fd8>] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [<000000004651452f>] nmi_cpu_backtrace.cold+0x47/0x87 lib/nmi_backtrace.c:99 [<00000000dde36ab9>] nmi_trigger_cpumask_backtrace+0x124/0x155 lib/nmi_backtrace.c:60 [<000000006fb8ea04>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 [<00000000ae92b62c>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline] [<00000000ae92b62c>] check_hung_task kernel/hung_task.c:125 [inline] [<00000000ae92b62c>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline] [<00000000ae92b62c>] watchdog+0x661/0xae0 kernel/hung_task.c:239 [<00000000ab465723>] kthread+0x278/0x310 kernel/kthread.c:211 [<00000000d4c2d420>] 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 0xffffffff8280f302