INFO: task syz-executor4:13109 blocked for more than 140 seconds. Not tainted 4.18.0-rc5+ #158 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor4 D25208 13109 4548 0x00000004 Call Trace: context_switch kernel/sched/core.c:2853 [inline] __schedule+0x87c/0x1ed0 kernel/sched/core.c:3501 schedule+0xfb/0x450 kernel/sched/core.c:3545 __rwsem_down_write_failed_common+0x95d/0x1630 kernel/locking/rwsem-xadd.c:566 rwsem_down_write_failed+0xe/0x10 kernel/locking/rwsem-xadd.c:595 call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:117 __down_write arch/x86/include/asm/rwsem.h:142 [inline] down_write+0xaa/0x130 kernel/locking/rwsem.c:72 inode_lock include/linux/fs.h:715 [inline] vfs_setxattr+0x96/0x100 fs/xattr.c:219 setxattr+0x2ea/0x450 fs/xattr.c:451 path_setxattr+0x1e3/0x230 fs/xattr.c:470 __do_sys_setxattr fs/xattr.c:485 [inline] __se_sys_setxattr fs/xattr.c:481 [inline] __x64_sys_setxattr+0xc4/0x150 fs/xattr.c:481 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x455ab9 Code: e0 1f 48 89 04 24 e8 b6 6f fd ff e8 81 6a fd ff e8 5c 68 fd ff 48 8d 05 23 cd 48 00 48 89 04 24 48 c7 44 24 08 1d 00 00 00 e8 <13> 5e fd ff 0f 0b e8 8c 44 00 00 e9 07 f0 ff ff cc cc cc cc cc cc RSP: 002b:00007f551a857c68 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc RAX: ffffffffffffffda RBX: 00007f551a8586d4 RCX: 0000000000455ab9 RDX: 0000000020000400 RSI: 0000000020000380 RDI: 0000000020000140 RBP: 000000000072bff0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004bbc29 R14: 00000000004d31b0 R15: 0000000000000002 Showing all locks held in the system: 1 lock held by khungtaskd/902: #0: 000000005ed69e66 (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x428 kernel/locking/lockdep.c:4461 1 lock held by rsyslogd/4405: 2 locks held by getty/4495: #0: 00000000df884136 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000b834c1c5 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4496: #0: 00000000c50dc714 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000075c32e96 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4497: #0: 00000000cc621347 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000b6a86074 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4498: #0: 00000000d9f24f9d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000095abdda (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4499: #0: 00000000e49f5739 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000a2efe4bb (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4500: #0: 00000000b595bd71 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000d22a07b5 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4501: #0: 000000002ab37ea4 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000006df015e7 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by syz-executor4/13021: #0: 00000000dd54d6aa (sb_writers#20){.+.+}, at: sb_start_write include/linux/fs.h:1554 [inline] #0: 00000000dd54d6aa (sb_writers#20){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:386 #1: 00000000b02dcf44 (&sb->s_type->i_mutex_key#22){+.+.}, at: inode_lock include/linux/fs.h:715 [inline] #1: 00000000b02dcf44 (&sb->s_type->i_mutex_key#22){+.+.}, at: vfs_setxattr+0x96/0x100 fs/xattr.c:219 2 locks held by syz-executor4/13109: #0: 00000000dd54d6aa (sb_writers#20){.+.+}, at: sb_start_write include/linux/fs.h:1554 [inline] #0: 00000000dd54d6aa (sb_writers#20){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:386 #1: 00000000b02dcf44 (&sb->s_type->i_mutex_key#22){+.+.}, at: inode_lock include/linux/fs.h:715 [inline] #1: 00000000b02dcf44 (&sb->s_type->i_mutex_key#22){+.+.}, at: vfs_setxattr+0x96/0x100 fs/xattr.c:219 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 902 Comm: khungtaskd Not tainted 4.18.0-rc5+ #158 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+0x1c9/0x2b4 lib/dump_stack.c:113 nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103 nmi_trigger_cpumask_backtrace+0x151/0x192 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:138 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:196 [inline] watchdog+0x9c4/0xf80 kernel/hung_task.c:252 kthread+0x345/0x410 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54