INFO: task syz-executor2:5443 blocked for more than 140 seconds. Not tainted 4.19.0-rc6+ #265 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor2 D18952 5443 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:2825 [inline] __schedule+0x86c/0x1ed0 kernel/sched/core.c:3473 schedule+0xfe/0x460 kernel/sched/core.c:3517 __rwsem_down_write_failed_common+0xbb9/0x1670 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+0xa5/0x130 kernel/locking/rwsem.c:72 inode_lock include/linux/fs.h:738 [inline] vfs_unlink+0xd1/0x510 fs/namei.c:3991 do_unlinkat+0x6cc/0xa30 fs/namei.c:4063 __do_sys_unlink fs/namei.c:4110 [inline] __se_sys_unlink fs/namei.c:4108 [inline] __x64_sys_unlink+0x42/0x50 fs/namei.c:4108 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4572c7 Code: 76 29 48 83 ec 10 48 89 6c 24 08 48 8d 6c 24 08 48 8b 42 08 48 8b 40 08 48 89 04 24 e8 02 d3 fc ff 48 8b 6c 24 08 48 83 c4 10 e8 e3 2b 00 00 eb c1 cc 64 48 8b 0c 25 f8 ff ff ff 48 3b 61 10 RSP: 002b:00007ffee3726338 EFLAGS: 00000246 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000004572c7 RDX: 00007ffee3726350 RSI: 00007ffee3726350 RDI: 00007ffee37263e0 RBP: 0000000000000e5e R08: 0000000000000000 R09: 000000000000000b R10: 0000000000000005 R11: 0000000000000246 R12: 00007ffee3727470 R13: 000000000225a940 R14: 0000000000000000 R15: 0000000000000002 Showing all locks held in the system: 1 lock held by khungtaskd/983: #0: 000000003d77b7ce (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4435 1 lock held by rsyslogd/5283: #0: 00000000648b4551 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 2 locks held by getty/5373: #0: 000000004adec3a8 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000006d46a8e5 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5374: #0: 0000000079c92cc4 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000002050fa40 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5375: #0: 0000000043bff109 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000000549834d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5376: #0: 000000007b4d62a2 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000008ba79cdd (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5377: #0: 000000004410b548 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000b818d671 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5378: #0: 000000002b7fdff3 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000006b3e3d75 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5379: #0: 00000000ac38141b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000da5ca006 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 3 locks held by syz-executor2/5443: #0: 00000000817189ae (sb_writers#3){.+.+}, at: sb_start_write include/linux/fs.h:1566 [inline] #0: 00000000817189ae (sb_writers#3){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:360 #1: 0000000088766420 (&type->i_mutex_dir_key#3/1){+.+.}, at: inode_lock_nested include/linux/fs.h:773 [inline] #1: 0000000088766420 (&type->i_mutex_dir_key#3/1){+.+.}, at: do_unlinkat+0x3d8/0xa30 fs/namei.c:4049 #2: 000000007d1a8038 (&sb->s_type->i_mutex_key#10){++++}, at: inode_lock include/linux/fs.h:738 [inline] #2: 000000007d1a8038 (&sb->s_type->i_mutex_key#10){++++}, at: vfs_unlink+0xd1/0x510 fs/namei.c:3991 2 locks held by syz-executor2/4562: #0: 00000000817189ae (sb_writers#3){.+.+}, at: file_start_write include/linux/fs.h:2759 [inline] #0: 00000000817189ae (sb_writers#3){.+.+}, at: vfs_write+0x42a/0x560 fs/read_write.c:548 #1: 000000007d1a8038 (&sb->s_type->i_mutex_key#10){++++}, at: inode_trylock include/linux/fs.h:758 [inline] #1: 000000007d1a8038 (&sb->s_type->i_mutex_key#10){++++}, at: ext4_file_write_iter+0x2a1/0x1420 fs/ext4/file.c:232 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 983 Comm: khungtaskd Not tainted 4.19.0-rc6+ #265 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+0x1c4/0x2b4 lib/dump_stack.c:113 nmi_cpu_backtrace.cold.3+0x63/0xa2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b3/0x1ed 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:144 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:204 [inline] watchdog+0xb3e/0x1050 kernel/hung_task.c:265 kthread+0x35a/0x420 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 5400 Comm: syz-fuzzer Not tainted 4.19.0-rc6+ #265 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0033:0x434681 Code: 48 89 6c 24 10 48 8d 6c 24 10 48 8d 05 08 98 09 01 48 89 04 24 e8 ef ad fd ff 48 8b 05 20 98 09 01 48 85 c0 74 1e 48 8b 48 10 <48> 89 0d 10 98 09 01 b9 ff ff ff ff 48 8d 15 0c 98 09 01 f0 0f c1 RSP: 002b:00007fff4458dc18 EFLAGS: 00000206 RAX: 000000c420018000 RBX: 00007fff4458dc68 RCX: 000000c420019300 RDX: 00000000014cde70 RSI: 0000000000459df0 RDI: 0000000000459000 RBP: 00007fff4458dc28 R08: 000000c42006c300 R09: 0000010f08992dd3 R10: 001022a06b800000 R11: 0000000000000001 R12: 0000000000000001 R13: 0000000000000014 R14: 000000000045b6a0 R15: 0000000000000000 FS: 00000000014cea28 GS: 0000000000000000