INFO: task syz-executor.1:24224 blocked for more than 140 seconds. Not tainted 4.9.194+ #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D25544 24224 1 0x00000004 0000000000000083 ffff8801a68d8000 0000000000000000 ffff8801db721000 ffff8801da6b2f80 ffff8801db721018 ffff8801a0b8f688 ffffffff8281af8e 0000000041b58ab3 ffffffff82e2c730 00ffffff81204ef0 ffff8801db7218f0 Call Trace: [<00000000f05e7006>] schedule+0x92/0x1c0 kernel/sched/core.c:3546 [<00000000d5e0d4ca>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3579 [<00000000c57ad05f>] __mutex_lock_common kernel/locking/mutex.c:582 [inline] [<00000000c57ad05f>] mutex_lock_nested+0x38d/0x920 kernel/locking/mutex.c:621 [<00000000314f8ed0>] lo_open+0x1d/0xb0 drivers/block/loop.c:1621 [<0000000011263f6d>] __blkdev_get+0x268/0xeb0 fs/block_dev.c:1287 [<000000005d360706>] blkdev_get+0x2e8/0x920 fs/block_dev.c:1424 [<00000000931e02c8>] blkdev_open+0x1aa/0x250 fs/block_dev.c:1579 [<0000000072e8c3a7>] do_dentry_open+0x422/0xd20 fs/open.c:791 [<000000003ec35234>] vfs_open+0x105/0x230 fs/open.c:904 [<00000000a1e43a17>] do_last fs/namei.c:3541 [inline] [<00000000a1e43a17>] path_openat+0xbf5/0x2f60 fs/namei.c:3665 [<0000000053101ed9>] do_filp_open+0x1a1/0x280 fs/namei.c:3699 [<00000000c326f898>] do_sys_open+0x2f0/0x610 fs/open.c:1097 [<00000000f0c78263>] SYSC_open fs/open.c:1115 [inline] [<00000000f0c78263>] SyS_open+0x2d/0x40 fs/open.c:1110 [<000000004a7334ae>] do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288 [<00000000e8133db3>] 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: [<0000000046226ec4>] check_hung_uninterruptible_tasks kernel/hung_task.c:169 [inline] #0: (rcu_read_lock){......}, at: [<0000000046226ec4>] watchdog+0x14b/0xaf0 kernel/hung_task.c:263 #1: (tasklist_lock){.+.+..}, at: [<00000000cb430b64>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4336 1 lock held by rsyslogd/1897: #0: (&f->f_pos_lock){+.+.+.}, at: [<000000007bdcff14>] __fdget_pos+0xa8/0xd0 fs/file.c:782 2 locks held by getty/2024: #0: (&tty->ldisc_sem){++++++}, at: [<00000000e3163074>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.+.}, at: [<00000000db88952c>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.1/24224: #0: (&bdev->bd_mutex){+.+.+.}, at: [<0000000016a2c92e>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<00000000314f8ed0>] lo_open+0x1d/0xb0 drivers/block/loop.c:1621 2 locks held by syz-executor.4/32025: #0: (&bdev->bd_mutex){+.+.+.}, at: [<0000000016a2c92e>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<00000000314f8ed0>] lo_open+0x1d/0xb0 drivers/block/loop.c:1621 2 locks held by syz-executor.2/814: #0: (&bdev->bd_mutex){+.+.+.}, at: [<0000000016a2c92e>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<00000000314f8ed0>] lo_open+0x1d/0xb0 drivers/block/loop.c:1621 2 locks held by syz-executor.5/7515: #0: (loop_index_mutex){+.+.+.}, at: [<00000000833af990>] loop_control_ioctl+0x7a/0x320 drivers/block/loop.c:1973 #1: (&lo->lo_ctl_mutex#2){+.+.+.}, at: [<00000000202a24da>] loop_control_ioctl+0x17f/0x320 drivers/block/loop.c:1987 2 locks held by syz-executor.0/7523: #0: (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<0000000081e6042c>] lo_ioctl+0x8e/0x1b10 drivers/block/loop.c:1404 #1: (&bdev->bd_mutex){+.+.+.}, at: [<00000000ff1e0a09>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:189 2 locks held by syz-executor.0/7542: #0: (&bdev->bd_mutex){+.+.+.}, at: [<0000000016a2c92e>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<00000000314f8ed0>] lo_open+0x1d/0xb0 drivers/block/loop.c:1621 1 lock held by blkid/7531: #0: (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<0000000081e6042c>] lo_ioctl+0x8e/0x1b10 drivers/block/loop.c:1404 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 24 Comm: khungtaskd Not tainted 4.9.194+ #0 ffff8801d98d7cc8 ffffffff81b67001 0000000000000000 0000000000000000 0000000000000000 ffffffff81099d01 dffffc0000000000 ffff8801d98d7d00 ffffffff81b7229c 0000000000000000 0000000000000000 0000000000000000 Call Trace: [<00000000ac4faba8>] __dump_stack lib/dump_stack.c:15 [inline] [<00000000ac4faba8>] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [<0000000090620d07>] nmi_cpu_backtrace.cold+0x47/0x87 lib/nmi_backtrace.c:99 [<00000000bceef413>] nmi_trigger_cpumask_backtrace+0x124/0x155 lib/nmi_backtrace.c:60 [<000000008caf5d6d>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 [<00000000a5545371>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline] [<00000000a5545371>] check_hung_task kernel/hung_task.c:126 [inline] [<00000000a5545371>] check_hung_uninterruptible_tasks kernel/hung_task.c:183 [inline] [<00000000a5545371>] watchdog+0x670/0xaf0 kernel/hung_task.c:263 [<00000000ee2cf750>] kthread+0x278/0x310 kernel/kthread.c:211 [<00000000f1eb1e56>] 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 CPU: 1 PID: 25487 Comm: syz-executor.1 Not tainted 4.9.194+ #0 task: 0000000052bb10e9 task.stack: 0000000065633ded RIP: 0010:[] c [<00000000d741e960>] __sanitizer_cov_trace_pc+0x26/0x50 kernel/kcov.c:100 RSP: 0018:ffff8801a497f8e0 EFLAGS: 00000246 RAX: ffff88019ecd2f80 RBX: ffff8801a497fac8 RCX: 1ffff1003492ff58 RDX: 0000000000000000 RSI: ffffffff812a03d2 RDI: ffff8801d26abc80 RBP: ffff8801a497f8e0 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000001 R12: ffff8801d26abc80 R13: ffffed003492ff4c R14: ffff8801a497fab8 R15: ffff8801d9c60080 FS: 00000000200002c0(0000) GS:ffff8801db700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f068fcf9f80 CR3: 00000001a3f53000 CR4: 00000000001606b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffff8801a497f900c ffffffff812a03d2c ffff8801d9c60080c 0000000020000548c ffff8801a497f9e0c ffffffff812a1b51c 0000000000000000c ffff8801a497fab0c 0000000b00000004c 1ffff1003492ff2bc dffffc0000000000c 0000000000000000c Call Trace: [<00000000bc666b8a>] drop_futex_key_refs.isra.0+0x12/0xd0 kernel/futex.c:460 [<00000000dd5ea2d0>] put_futex_key kernel/futex.c:707 [inline] [<00000000dd5ea2d0>] futex_wait_setup+0x201/0x350 kernel/futex.c:2449 [<0000000021cc325f>] futex_wait+0x1e6/0x5d0 kernel/futex.c:2482 [<0000000098a9006f>] do_futex+0x159/0x1a70 kernel/futex.c:3277 [<00000000ac766ab7>] SYSC_futex kernel/futex.c:3337 [inline] [<00000000ac766ab7>] SyS_futex+0x253/0x360 kernel/futex.c:3305 [<000000004a7334ae>] do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288 [<00000000e8133db3>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Code: c00 c0f c1f c40 c00 c55 c48 c89 ce5 c48 c8b c75 c08 c65 c48 c8b c04 c25 c00 c7e c01 c00 c65 c8b c15 c78 c56 ccf c7e c81 ce2 c00 c01 c1f c00 c75 c2b c8b c90 c38 c12 c00 c00 c<83> cfa c02 c75 c20 c48 c8b c88 c40 c12 c00 c00 c8b c80 c3c c12 c00 c00 c48 c8b c11 c