INFO: task syz-executor.4:15643 blocked for more than 140 seconds. Not tainted 5.0.0-rc8+ #2 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D29216 15643 7519 0x00000004 Call Trace: context_switch kernel/sched/core.c:2844 [inline] __schedule+0x817/0x1cc0 kernel/sched/core.c:3485 schedule+0x92/0x180 kernel/sched/core.c:3529 request_wait_answer+0x42f/0x7c0 fs/fuse/dev.c:530 __fuse_request_send+0x12b/0x1d0 fs/fuse/dev.c:550 fuse_request_send+0x60/0xa0 fs/fuse/dev.c:563 fuse_simple_request+0x2f6/0x730 fs/fuse/dev.c:621 fuse_removexattr+0x1a4/0x2f0 fs/fuse/xattr.c:165 fuse_xattr_set+0x61/0x66 fs/fuse/xattr.c:190 __vfs_removexattr+0x112/0x180 fs/xattr.c:376 vfs_removexattr+0xb7/0x200 fs/xattr.c:395 removexattr+0xda/0x130 fs/xattr.c:690 path_removexattr+0x166/0x180 fs/xattr.c:704 __do_sys_removexattr fs/xattr.c:718 [inline] __se_sys_removexattr fs/xattr.c:715 [inline] __x64_sys_removexattr+0x59/0x80 fs/xattr.c:715 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457e29 Code: 24 28 48 89 4c 24 08 66 c7 44 24 10 01 01 48 c7 44 24 18 00 00 00 00 e8 a5 b0 fc ff 48 8b 44 24 38 48 89 04 24 e8 d7 77 fb ff <48> 8b 6c 24 40 48 83 c4 48 c3 48 89 d1 eb 90 e8 73 20 00 00 e9 7e RSP: 002b:00007f35381f0c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000c5 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 0000000000457e29 RDX: 0000000000000000 RSI: 0000000020000500 RDI: 00000000200003c0 RBP: 000000000073bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f35381f16d4 R13: 00000000004be5e4 R14: 00000000004d86c0 R15: 00000000ffffffff Showing all locks held in the system: 1 lock held by khungtaskd/1039: #0: 0000000016239c05 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:4389 1 lock held by rsyslogd/7357: #0: 00000000d5e69206 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:795 2 locks held by getty/7469: #0: 0000000063592085 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000402e2ba6 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2154 2 locks held by getty/7470: #0: 0000000087f9257b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000b93b8e78 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2154 2 locks held by getty/7471: #0: 000000006d93210e (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000de1b3cbf (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2154 2 locks held by getty/7472: #0: 0000000093a7e1e3 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000f0089cad (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2154 2 locks held by getty/7473: #0: 0000000047cc73ee (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000e468dbbe (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2154 2 locks held by getty/7474: #0: 00000000a02d2869 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000001143463b (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2154 2 locks held by getty/7475: #0: 000000002fc0a92f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000016622d09 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2154 2 locks held by syz-executor.4/15643: #0: 00000000e9b6b1ed (sb_writers#21){.+.+}, at: sb_start_write include/linux/fs.h:1603 [inline] #0: 00000000e9b6b1ed (sb_writers#21){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:357 #1: 00000000b24cad6a (&type->i_mutex_dir_key#8){+.+.}, at: inode_lock include/linux/fs.h:757 [inline] #1: 00000000b24cad6a (&type->i_mutex_dir_key#8){+.+.}, at: vfs_removexattr+0x8b/0x200 fs/xattr.c:390 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1039 Comm: khungtaskd Not tainted 5.0.0-rc8+ #2 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+0x172/0x1f0 lib/dump_stack.c:113 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1be/0x236 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline] watchdog+0x9df/0xee0 kernel/hung_task.c:287 kthread+0x357/0x430 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at native_safe_halt+0x2/0x10 arch/x86/include/asm/irqflags.h:57