INFO: task syz-executor204:7962 blocked for more than 140 seconds. Not tainted 4.14.253-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor204 D28376 7962 7959 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3384 schedule+0x8d/0x1b0 kernel/sched/core.c:3428 fuse_wait_on_page_writeback fs/fuse/file.c:382 [inline] fuse_wait_on_page_writeback.isra.0+0xdc/0x120 fs/fuse/file.c:378 fuse_launder_page fs/fuse/file.c:2032 [inline] fuse_launder_page+0xa2/0xd0 fs/fuse/file.c:2025 do_launder_page mm/truncate.c:609 [inline] invalidate_inode_pages2_range+0x547/0xc00 mm/truncate.c:685 fuse_finish_open+0x262/0x500 fs/fuse/file.c:181 fuse_open_common+0x1fc/0x250 fs/fuse/file.c:221 do_dentry_open+0x44b/0xec0 fs/open.c:777 vfs_open+0x105/0x220 fs/open.c:888 do_last fs/namei.c:3428 [inline] path_openat+0x628/0x2970 fs/namei.c:3569 do_filp_open+0x179/0x3c0 fs/namei.c:3603 do_sys_open+0x296/0x410 fs/open.c:1081 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7fc5be92f539 RSP: 002b:00007fc5be8bf2f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000055 RAX: ffffffffffffffda RBX: 00007fc5be9c04d0 RCX: 00007fc5be92f539 RDX: 00007fc5be92f539 RSI: 0000000000000000 RDI: 0000000020000280 RBP: 00007fc5be98d164 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0030656c69662f2e R13: 00007fc5be989158 R14: 00007fc5be98b160 R15: 00007fc5be9c04d8 Showing all locks held in the system: 1 lock held by khungtaskd/1517: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 2 locks held by syz-executor204/7962: #0: (sb_writers#10){.+.+}, at: [] sb_start_write include/linux/fs.h:1549 [inline] #0: (sb_writers#10){.+.+}, at: [] mnt_want_write+0x3a/0xb0 fs/namespace.c:386 #1: (&sb->s_type->i_mutex_key#17){+.+.}, at: [] inode_lock include/linux/fs.h:719 [inline] #1: (&sb->s_type->i_mutex_key#17){+.+.}, at: [] fuse_open_common+0x177/0x250 fs/fuse/file.c:214 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1517 Comm: khungtaskd Not tainted 4.14.253-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x281 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x13a/0x180 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline] watchdog+0x5b9/0xb40 kernel/hung_task.c:274 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff87236c8e