INFO: task syz-executor367:7987 blocked for more than 140 seconds. Not tainted 4.14.281-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor367 D28696 7987 7982 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: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: 0033:0x7f4c81d403e9 RSP: 002b:00007f4c81cd02f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000055 RAX: ffffffffffffffda RBX: 00007f4c81dcf4d8 RCX: 00007f4c81d403e9 RDX: 00007f4c81d403e9 RSI: 0000000000000000 RDI: 00000000200001c0 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f4c81dcf4d0 R13: 00007fffbfc9234f R14: 00007f4c81d9c15c R15: 0030656c69662f2e Showing all locks held in the system: 1 lock held by khungtaskd/1533: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 2 locks held by syz-executor367/7987: #0: (sb_writers#10){.+.+}, at: [] sb_start_write include/linux/fs.h:1551 [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+0x1a4/0x290 fs/fuse/file.c:217 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1533 Comm: khungtaskd Not tainted 4.14.281-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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 8 Comm: rcu_preempt Not tainted 4.14.281-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8880b5420200 task.stack: ffff8880b5428000 RIP: 0010:reacquire_held_locks+0x5/0x3f0 kernel/locking/lockdep.c:3633 RSP: 0018:ffff8880b542fb60 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 1ffff11016a85f70 RCX: 1ffff11016a84151 RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffff8880b5420200 RBP: 0000000000000000 R08: ffffffff8b9c9430 R09: 0000000000000001 R10: 0000000000000000 R11: ffff8880b5420200 R12: 0000000000000000 R13: ffffffff8bed1d40 R14: ffff8880b5420200 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880ba400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe9f23fc000 CR3: 00000000a2293000 CR4: 00000000003406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __lock_release kernel/locking/lockdep.c:3797 [inline] lock_release+0x36b/0x870 kernel/locking/lockdep.c:4017 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:158 [inline] _raw_spin_unlock_irqrestore+0x1b/0xe0 kernel/locking/spinlock.c:192 try_to_del_timer_sync+0xaf/0xe0 kernel/time/timer.c:1183 del_timer_sync+0x17c/0x240 kernel/time/timer.c:1246 schedule_timeout+0x4b7/0xe90 kernel/time/timer.c:1748 rcu_gp_kthread+0xc0a/0x1e60 kernel/rcu/tree.c:2255 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Code: 24 68 4c 8b 54 24 60 0f b6 74 24 58 4c 8b 44 24 50 48 8b 54 24 48 e9 4e d5 ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 48 63 c2 39 d6 <48> 8d 04 80 48 8d 84 c7 88 08 00 00 0f 86 40 02 00 00 83 ee 01 ---------------- Code disassembly (best guess): 0: 24 68 and $0x68,%al 2: 4c 8b 54 24 60 mov 0x60(%rsp),%r10 7: 0f b6 74 24 58 movzbl 0x58(%rsp),%esi c: 4c 8b 44 24 50 mov 0x50(%rsp),%r8 11: 48 8b 54 24 48 mov 0x48(%rsp),%rdx 16: e9 4e d5 ff ff jmpq 0xffffd569 1b: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1) 22: 00 00 00 00 26: 48 63 c2 movslq %edx,%rax 29: 39 d6 cmp %edx,%esi * 2b: 48 8d 04 80 lea (%rax,%rax,4),%rax <-- trapping instruction 2f: 48 8d 84 c7 88 08 00 lea 0x888(%rdi,%rax,8),%rax 36: 00 37: 0f 86 40 02 00 00 jbe 0x27d 3d: 83 ee 01 sub $0x1,%esi