INFO: task syz-executor820:8020 blocked for more than 140 seconds.
      Not tainted 4.14.298-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor820 D28648  8020   8018 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2811 [inline]
 __schedule+0x88b/0x1de0 kernel/sched/core.c:3387
 schedule+0x8d/0x1b0 kernel/sched/core.c:3431
 fuse_wait_on_page_writeback fs/fuse/file.c:385 [inline]
 fuse_wait_on_page_writeback.isra.0+0xdc/0x120 fs/fuse/file.c:381
 fuse_launder_page fs/fuse/file.c:2042 [inline]
 fuse_launder_page+0xa2/0xd0 fs/fuse/file.c:2035
 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+0x234/0x290 fs/fuse/file.c:224
 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:3571
 do_filp_open+0x179/0x3c0 fs/namei.c:3605
 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+0x5e/0xd3

Showing all locks held in the system:
1 lock held by khungtaskd/1531:
 #0:  (tasklist_lock){.+.+}, at: [<ffffffff8702a559>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548
2 locks held by syz-executor820/8020:
 #0:  (sb_writers#10){.+.+}, at: [<ffffffff818e1bca>] sb_start_write include/linux/fs.h:1551 [inline]
 #0:  (sb_writers#10){.+.+}, at: [<ffffffff818e1bca>] mnt_want_write+0x3a/0xb0 fs/namespace.c:386
 #1:  (&sb->s_type->i_mutex_key#17){+.+.}, at: [<ffffffff822f7664>] inode_lock include/linux/fs.h:719 [inline]
 #1:  (&sb->s_type->i_mutex_key#17){+.+.}, at: [<ffffffff822f7664>] fuse_open_common+0x1a4/0x290 fs/fuse/file.c:217

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 1531 Comm: khungtaskd Not tainted 4.14.298-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
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:406
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff8724adce