INFO: task syz-executor2:16802 blocked for more than 140 seconds. Not tainted 4.18.0+ #209 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor2 D24640 16802 4480 0x00000004 Call Trace: context_switch kernel/sched/core.c:2825 [inline] __schedule+0x87c/0x1df0 kernel/sched/core.c:3473 schedule+0xfb/0x450 kernel/sched/core.c:3517 __rwsem_down_write_failed_common+0x98b/0x1650 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_nested+0xae/0x130 kernel/locking/rwsem.c:194 inode_lock_nested include/linux/fs.h:773 [inline] do_unlinkat+0x3d8/0xa30 fs/namei.c:4049 __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: 0033:0x457089 Code: 08 e8 3b a9 fb ff 48 8b 44 24 20 48 8b 4c 24 18 48 8b 54 24 38 48 8b 7c 24 48 eb 8d 48 8b 6c 24 50 48 83 c4 58 c3 48 89 04 24 <48> 89 5c 24 08 e8 0d a9 fb ff 48 8b 44 24 40 48 8b 4c 24 48 48 8b RSP: 002b:00007f97f6516c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 00007f97f65176d4 RCX: 0000000000457089 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000040 RBP: 0000000000930140 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d6d50 R14: 00000000004c7ae7 R15: 0000000000000001 INFO: task syz-executor2:16803 blocked for more than 140 seconds. Not tainted 4.18.0+ #209 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor2 D24016 16803 4480 0x00000004 Call Trace: context_switch kernel/sched/core.c:2825 [inline] __schedule+0x87c/0x1df0 kernel/sched/core.c:3473 schedule+0xfb/0x450 kernel/sched/core.c:3517 __rwsem_down_write_failed_common+0x98b/0x1650 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:738 [inline] lock_mount+0x8c/0x2e0 fs/namespace.c:2053 do_add_mount+0x27/0x370 fs/namespace.c:2430 do_new_mount fs/namespace.c:2497 [inline] do_mount+0x193f/0x30e0 fs/namespace.c:2813 ksys_mount+0x12d/0x140 fs/namespace.c:3029 __do_sys_mount fs/namespace.c:3043 [inline] __se_sys_mount fs/namespace.c:3040 [inline] __x64_sys_mount+0xbe/0x150 fs/namespace.c:3040 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457089 Code: 08 e8 3b a9 fb ff 48 8b 44 24 20 48 8b 4c 24 18 48 8b 54 24 38 48 8b 7c 24 48 eb 8d 48 8b 6c 24 50 48 83 c4 58 c3 48 89 04 24 <48> 89 5c 24 08 e8 0d a9 fb ff 48 8b 44 24 40 48 8b 4c 24 48 48 8b RSP: 002b:00007f97f64f5c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f97f64f66d4 RCX: 0000000000457089 RDX: 00000000200008c0 RSI: 0000000020000000 RDI: 0000000000000000 RBP: 00000000009301e0 R08: 0000000020000a80 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d2838 R14: 00000000004c7c60 R15: 0000000000000002 Showing all locks held in the system: 1 lock held by khungtaskd/776: #0: 0000000038b9ca57 (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x428 kernel/locking/lockdep.c:4436 1 lock held by rsyslogd/4340: 2 locks held by getty/4431: #0: 00000000db1fbceb (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000001899b836 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4432: #0: 00000000da30a142 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000003244e923 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4433: #0: 0000000044309b49 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000006849d4ce (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4434: #0: 00000000af7ff26f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000707fe91c (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4435: #0: 000000006dac9c64 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000007b822fbf (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4436: #0: 00000000b395508c (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000003b7fe21a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4437: #0: 000000006deca612 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000d5c47e26 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 3 locks held by syz-executor2/16743: #0: 0000000014bb46ae (sb_writers#20){.+.+}, at: sb_start_write include/linux/fs.h:1566 [inline] #0: 0000000014bb46ae (sb_writers#20){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:386 #1: 000000007dff71d8 (&sb->s_type->i_mutex_key#23/1){+.+.}, at: inode_lock_nested include/linux/fs.h:773 [inline] #1: 000000007dff71d8 (&sb->s_type->i_mutex_key#23/1){+.+.}, at: do_unlinkat+0x3d8/0xa30 fs/namei.c:4049 #2: 0000000036b8533e (&sb->s_type->i_mutex_key#23){++++}, at: inode_lock include/linux/fs.h:738 [inline] #2: 0000000036b8533e (&sb->s_type->i_mutex_key#23){++++}, at: vfs_unlink+0xd1/0x510 fs/namei.c:3991 2 locks held by syz-executor2/16802: #0: 0000000014bb46ae (sb_writers#20){.+.+}, at: sb_start_write include/linux/fs.h:1566 [inline] #0: 0000000014bb46ae (sb_writers#20){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:386 #1: 000000007dff71d8 (&sb->s_type->i_mutex_key#23/1){+.+.}, at: inode_lock_nested include/linux/fs.h:773 [inline] #1: 000000007dff71d8 (&sb->s_type->i_mutex_key#23/1){+.+.}, at: do_unlinkat+0x3d8/0xa30 fs/namei.c:4049 1 lock held by syz-executor2/16803: #0: 000000007dff71d8 (&sb->s_type->i_mutex_key#23){++++}, at: inode_lock include/linux/fs.h:738 [inline] #0: 000000007dff71d8 (&sb->s_type->i_mutex_key#23){++++}, at: lock_mount+0x8c/0x2e0 fs/namespace.c:2053 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 776 Comm: khungtaskd Not tainted 4.18.0+ #209 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.3+0x48/0x88 lib/nmi_backtrace.c:101 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:144 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:204 [inline] watchdog+0xb39/0x1040 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.18.0+ #209 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:reschedule_interrupt+0x0/0x20 arch/x86/entry/entry_64.S:887 Code: 66 2e 0f 1f 84 00 00 00 00 00 68 03 ff ff ff e8 56 f2 ff ff e8 d1 27 00 00 e9 4b f3 ff ff 66 90 66 2e 0f 1f 84 00 00 00 00 00 <68> 02 ff ff ff e8 36 f2 ff ff e8 d1 21 00 00 e9 2b f3 ff ff 66 90 RSP: 0018:ffff8801d9f27c08 EFLAGS: 00000082 RAX: dffffc0000000000 RBX: 1ffff1003b3e4f8a RCX: 0000000000000000 RDX: 1ffffffff0fe37a0 RSI: 0000000000000001 RDI: ffffffff87f1bd00 RBP: ffff8801d9f27c30 R08: ffff8801d9f1a380 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: ffff8801d9f27cf0 R14: 0000000000000001 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8801db100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600400 CR3: 00000001cf4fc000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline] default_idle+0xc2/0x410 arch/x86/kernel/process.c:498 arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:489 default_idle_call+0x6d/0x90 kernel/sched/idle.c:93 cpuidle_idle_call kernel/sched/idle.c:153 [inline] do_idle+0x3aa/0x580 kernel/sched/idle.c:262 cpu_startup_entry+0x10c/0x120 kernel/sched/idle.c:368 start_secondary+0x433/0x5d0 arch/x86/kernel/smpboot.c:271 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:242