INFO: task syz-executor251:8112 blocked for more than 140 seconds. Not tainted 4.19.211-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor251 D27376 8112 8110 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x887/0x2040 kernel/sched/core.c:3517 schedule+0x8d/0x1b0 kernel/sched/core.c:3561 fuse_wait_on_page_writeback fs/fuse/file.c:383 [inline] fuse_wait_on_page_writeback.isra.0+0x11b/0x170 fs/fuse/file.c:379 fuse_launder_page fs/fuse/file.c:2033 [inline] fuse_launder_page+0xb6/0xe0 fs/fuse/file.c:2026 do_launder_page mm/truncate.c:655 [inline] invalidate_inode_pages2_range+0x795/0x1110 mm/truncate.c:725 fuse_finish_open+0x2e2/0x590 fs/fuse/file.c:182 fuse_open_common+0x254/0x2c0 fs/fuse/file.c:222 do_dentry_open+0x4aa/0x1160 fs/open.c:796 do_last fs/namei.c:3421 [inline] path_openat+0x793/0x2df0 fs/namei.c:3537 do_filp_open+0x18c/0x3f0 fs/namei.c:3567 do_sys_open+0x3b3/0x520 fs/open.c:1085 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7fa996ef04c9 Code: Bad RIP value. RSP: 002b:00007fa996ea12f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000055 RAX: ffffffffffffffda RBX: 00007fa996f814c0 RCX: 00007fa996ef04c9 RDX: 00007fa996ef04c9 RSI: 0000000000000000 RDI: 00000000200001c0 RBP: 00007fa996f4e164 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0030656c69662f2e R13: 00007fa996f4a158 R14: 00007fa996f4c160 R15: 00007fa996f814c8 Showing all locks held in the system: 1 lock held by khungtaskd/1570: #0: 0000000035c43735 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4441 2 locks held by syz-executor251/8112: #0: 000000002688605b (sb_writers#11){.+.+}, at: sb_start_write include/linux/fs.h:1579 [inline] #0: 000000002688605b (sb_writers#11){.+.+}, at: mnt_want_write+0x3a/0xb0 fs/namespace.c:360 #1: 00000000a847ca6e (&sb->s_type->i_mutex_key#17){+.+.}, at: inode_lock include/linux/fs.h:748 [inline] #1: 00000000a847ca6e (&sb->s_type->i_mutex_key#17){+.+.}, at: fuse_open_common+0x1bc/0x2c0 fs/fuse/file.c:215 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1570 Comm: khungtaskd Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1a6/0x1f0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline] watchdog+0x991/0xe60 kernel/hung_task.c:287 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 4693 Comm: systemd-journal Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__list_del_entry_valid+0xaf/0xf0 lib/list_debug.c:54 Code: 75 51 49 8b 14 24 48 39 ea 0f 85 e8 51 85 04 49 8d 7d 08 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 22 <49> 8b 55 08 48 39 ea 0f 85 f9 51 85 04 5d b8 01 00 00 00 41 5c 41 RSP: 0018:ffff8880a0f0f908 EFLAGS: 00010046 RAX: dffffc0000000000 RBX: 0000000000000001 RCX: 0000000000000000 RDX: 1ffffd40004ebdb2 RSI: 0000000000000068 RDI: ffffea000275ed90 RBP: ffffea0002c19708 R08: 0000000000000001 R09: ffffed1027fff788 R10: ffff88813fffbc43 R11: 0000000000000000 R12: ffff88813fffb828 R13: ffffea000275ed88 R14: ffff88813fffb6c0 R15: dffffc0000000000 FS: 00007f68064ed8c0(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f68038be010 CR3: 00000000a0c6c000 CR4: 00000000003406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __list_del_entry include/linux/list.h:117 [inline] list_del include/linux/list.h:125 [inline] __rmqueue_smallest mm/page_alloc.c:1985 [inline] __rmqueue mm/page_alloc.c:2475 [inline] rmqueue mm/page_alloc.c:3034 [inline] get_page_from_freelist+0x180f/0x4170 mm/page_alloc.c:3373 __alloc_pages_nodemask+0x387/0x2890 mm/page_alloc.c:4399 __alloc_pages include/linux/gfp.h:496 [inline] __alloc_pages_node include/linux/gfp.h:509 [inline] kmem_getpages mm/slab.c:1412 [inline] cache_grow_begin+0xa4/0x8a0 mm/slab.c:2682 cache_alloc_refill+0x273/0x340 mm/slab.c:3049 ____cache_alloc mm/slab.c:3132 [inline] __do_cache_alloc mm/slab.c:3354 [inline] slab_alloc mm/slab.c:3389 [inline] kmem_cache_alloc+0x346/0x370 mm/slab.c:3557 getname_flags+0xce/0x590 fs/namei.c:140 user_path_at_empty+0x2a/0x50 fs/namei.c:2609 user_path_at include/linux/namei.h:57 [inline] do_faccessat+0x248/0x7a0 fs/open.c:397 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f68057a89c7 Code: 83 c4 08 48 3d 01 f0 ff ff 73 01 c3 48 8b 0d c8 d4 2b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 b8 15 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d a1 d4 2b 00 f7 d8 64 89 01 48 RSP: 002b:00007fffdce30a08 EFLAGS: 00000246 ORIG_RAX: 0000000000000015 RAX: ffffffffffffffda RBX: 00007fffdce33a30 RCX: 00007f68057a89c7 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000561b090999a3 RBP: 00007fffdce30b50 R08: 0000561b0908f3e5 R09: 0000000000000018 R10: 0000000000000069 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000561b09f7f8a0 R15: 00007fffdce31040 ---------------- Code disassembly (best guess): 0: 75 51 jne 0x53 2: 49 8b 14 24 mov (%r12),%rdx 6: 48 39 ea cmp %rbp,%rdx 9: 0f 85 e8 51 85 04 jne 0x48551f7 f: 49 8d 7d 08 lea 0x8(%r13),%rdi 13: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 1a: fc ff df 1d: 48 89 fa mov %rdi,%rdx 20: 48 c1 ea 03 shr $0x3,%rdx 24: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) 28: 75 22 jne 0x4c * 2a: 49 8b 55 08 mov 0x8(%r13),%rdx <-- trapping instruction 2e: 48 39 ea cmp %rbp,%rdx 31: 0f 85 f9 51 85 04 jne 0x4855230 37: 5d pop %rbp 38: b8 01 00 00 00 mov $0x1,%eax 3d: 41 5c pop %r12 3f: 41 rex.B