INFO: task syz-executor1:15842 blocked for more than 140 seconds. Not tainted 4.9.125+ #37 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor1 D25384 15842 2112 0x00000004 ffff8801a1518000 ffff8801c7486e00 ffff8801d3bce880 ffff8801a01517c0 ffff8801db621018 ffff8801d2997160 ffffffff8277d092 ffff8801d2997100 ffffffff8278b918 ffff8801db621000 00ff8801d2997158 ffff8801db6218f0 Call Trace: [] schedule+0x7f/0x1b0 kernel/sched/core.c:3553 [] schedule_timeout+0x735/0xe20 kernel/time/timer.c:1768 [] io_schedule_timeout+0x1ba/0x390 kernel/sched/core.c:5176 [] io_schedule include/linux/sched.h:460 [inline] [] dio_await_one fs/direct-io.c:461 [inline] [] dio_await_completion fs/direct-io.c:515 [inline] [] do_blockdev_direct_IO fs/direct-io.c:1331 [inline] [] __blockdev_direct_IO+0x8b54/0xbd10 fs/direct-io.c:1360 [] ext4_direct_IO_write fs/ext4/inode.c:3507 [inline] [] ext4_direct_IO+0x978/0x29c0 fs/ext4/inode.c:3663 [] generic_file_direct_write+0x284/0x510 mm/filemap.c:2655 [] __generic_file_write_iter+0x21f/0x540 mm/filemap.c:2835 [] ext4_file_write_iter+0x63d/0xd70 fs/ext4/file.c:165 [] aio_write+0x2f2/0x510 fs/aio.c:1505 [] io_submit_one fs/aio.c:1586 [inline] [] do_io_submit+0xd35/0x1080 fs/aio.c:1654 [] SYSC_io_submit fs/aio.c:1679 [inline] [] SyS_io_submit+0x27/0x30 fs/aio.c:1676 [] do_syscall_64+0x19f/0x480 arch/x86/entry/common.c:282 [] 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: [] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline] #0: (rcu_read_lock){......}, at: [] watchdog+0x11c/0xa20 kernel/hung_task.c:239 #1: (tasklist_lock){.+.+..}, at: [] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336 2 locks held by getty/2021: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+...}, at: [] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142 1 lock held by syz-executor3/7551: #0: (sb_writers#4){.+.+.+}, at: [] file_start_write include/linux/fs.h:2640 [inline] #0: (sb_writers#4){.+.+.+}, at: [] do_sendfile+0xa80/0xc30 fs/read_write.c:1392 2 locks held by syz-executor1/15842: #0: (sb_writers#4){.+.+.+}, at: [] file_start_write include/linux/fs.h:2640 [inline] #0: (sb_writers#4){.+.+.+}, at: [] aio_write+0x3f3/0x510 fs/aio.c:1504 #1: (&sb->s_type->i_mutex_key#10){++++++}, at: [] inode_lock include/linux/fs.h:766 [inline] #1: (&sb->s_type->i_mutex_key#10){++++++}, at: [] ext4_file_write_iter+0x122/0xd70 fs/ext4/file.c:100 2 locks held by syz-executor1/15850: #0: (sb_writers#4){.+.+.+}, at: [] sb_start_write include/linux/fs.h:1573 [inline] #0: (sb_writers#4){.+.+.+}, at: [] mnt_want_write+0x3f/0xb0 fs/namespace.c:391 #1: (&sb->s_type->i_mutex_key#10){++++++}, at: [] inode_lock include/linux/fs.h:766 [inline] #1: (&sb->s_type->i_mutex_key#10){++++++}, at: [] do_truncate2+0x128/0x1f0 fs/open.c:61 2 locks held by syz-executor1/15875: #0: (sb_writers#4){.+.+.+}, at: [] file_start_write include/linux/fs.h:2640 [inline] #0: (sb_writers#4){.+.+.+}, at: [] vfs_write+0x3eb/0x520 fs/read_write.c:556 #1: (&sb->s_type->i_mutex_key#10){++++++}, at: [] inode_lock include/linux/fs.h:766 [inline] #1: (&sb->s_type->i_mutex_key#10){++++++}, at: [] ext4_file_write_iter+0x122/0xd70 fs/ext4/file.c:100 2 locks held by syz-executor1/15877: #0: (sb_writers#4){.+.+.+}, at: [] file_start_write include/linux/fs.h:2640 [inline] #0: (sb_writers#4){.+.+.+}, at: [] aio_write+0x3f3/0x510 fs/aio.c:1504 #1: (&sb->s_type->i_mutex_key#10){++++++}, at: [] inode_lock include/linux/fs.h:766 [inline] #1: (&sb->s_type->i_mutex_key#10){++++++}, at: [] ext4_file_write_iter+0x122/0xd70 fs/ext4/file.c:100 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 24 Comm: khungtaskd Not tainted 4.9.125+ #37 ffff8801d9907d08 ffffffff81af0ae9 0000000000000000 0000000000000000 0000000000000000 0000000000000001 ffffffff810967d0 ffff8801d9907d40 ffffffff81afb849 0000000000000000 0000000000000000 0000000000000003 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] nmi_cpu_backtrace.cold.0+0x48/0x87 lib/nmi_backtrace.c:99 [] nmi_trigger_cpumask_backtrace+0x12c/0x151 lib/nmi_backtrace.c:60 [] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 [] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline] [] check_hung_task kernel/hung_task.c:125 [inline] [] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline] [] watchdog+0x6ad/0xa20 kernel/hung_task.c:239 [] kthread+0x26d/0x300 kernel/kthread.c:211 [] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff8278ada6