INFO: task syz-executor0:5846 blocked for more than 120 seconds. Not tainted 4.9.78-ge9dabe6 #19 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor0 D29680 5846 3396 0x00000004 ffff8801c25d3000 ffff8801c19eef40 ffff8801cd830000 ffff8801c262e000 ffff8801db221b98 ffff8801c19c78e0 ffffffff838a1bbb 0000000041b58ab3 ffffffff84193238 00ffffff8123be20 ffff8801db222468 ffff8801db222490 Call Trace: [] schedule+0x7f/0x1b0 kernel/sched/core.c:3550 [] schedule_timeout+0x56c/0x10b0 kernel/time/timer.c:1768 [] io_schedule_timeout+0x1be/0x390 kernel/sched/core.c:5172 [] io_schedule include/linux/sched.h:460 [inline] [] bit_wait_io+0x19/0xa0 kernel/sched/wait.c:582 [] __wait_on_bit_lock+0xc2/0x1c0 kernel/sched/wait.c:421 [] __lock_page+0xff/0x160 mm/filemap.c:934 [] lock_page include/linux/pagemap.h:454 [inline] [] pagecache_get_page+0x436/0x710 mm/filemap.c:1216 [] find_lock_page include/linux/pagemap.h:284 [inline] [] truncate_inode_pages_range+0x655/0x12c0 mm/truncate.c:320 [] blkdev_fallocate+0x221/0x440 fs/block_dev.c:1817 [] vfs_fallocate+0x33a/0x5f0 fs/open.c:329 [] SYSC_fallocate fs/open.c:352 [inline] [] SyS_fallocate+0x53/0x90 fs/open.c:346 [] entry_SYSCALL_64_fastpath+0x29/0xe8 Showing all locks held in the system: 2 locks held by khungtaskd/514: #0: (rcu_read_lock){......}, at: [] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline] #0: (rcu_read_lock){......}, at: [] watchdog+0x125/0xa70 kernel/hung_task.c:239 #1: (tasklist_lock){.+.+..}, at: [] debug_show_all_locks+0x70/0x280 kernel/locking/lockdep.c:4336 1 lock held by rsyslogd/3179: #0: (&f->f_pos_lock){+.+.+.}, at: [] __fdget_pos+0x9f/0xc0 fs/file.c:781 2 locks held by getty/3306: #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+0x1f4/0x16c0 drivers/tty/n_tty.c:2133 1 lock held by syz-executor0/5846: #0: (sb_writers){.+.+.+}, at: [] sb_start_write include/linux/fs.h:1554 [inline] #0: (sb_writers){.+.+.+}, at: [] vfs_fallocate+0x2e1/0x5f0 fs/open.c:328 1 lock held by syz-executor0/5855: #0: (&lo->lo_ctl_mutex/1){+.+.+.}, at: [] lo_ioctl+0x8f/0x1990 drivers/block/loop.c:1337 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 514 Comm: khungtaskd Not tainted 4.9.78-ge9dabe6 #19 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ffff8801d8bb7d00 ffffffff81d943a9 0000000000000000 0000000000000001 0000000000000001 0000000000000001 ffffffff810bac10 ffff8801d8bb7d38 ffffffff81d9f4cd 0000000000000001 0000000000000000 ffff8801c1ffe418 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] nmi_cpu_backtrace+0xfd/0x120 lib/nmi_backtrace.c:99 [] nmi_trigger_cpumask_backtrace+0x117/0x190 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+0x6f0/0xa70 kernel/hung_task.c:239 [] kthread+0x26d/0x300 kernel/kthread.c:211 [] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:477 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff838b18a6