INFO: task syz-executor0:12037 blocked for more than 140 seconds.
Not tainted 4.9.124-g09eb2ba #31
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0 D29880 12037 3869 0x00000004
ffff8801997cb000 0000000000000000 ffff8801cdde8fc0 ffff8801cdda3000
ffff8801db221c18 ffff8801d6ee7ab8 ffffffff839f0afd ffffffff81237da7
0000000000000000 ffff8801997cb8c0 0000000600000007 ffff8801db2224e8
Call Trace:
[<ffffffff839f20ff>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
[<ffffffff839fd738>] __rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:526 [inline]
[<ffffffff839fd738>] rwsem_down_write_failed+0x598/0x990 kernel/locking/rwsem-xadd.c:555
[<ffffffff81eed907>] call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:105
[<ffffffff8122e530>] __down_write arch/x86/include/asm/rwsem.h:125 [inline]
[<ffffffff8122e530>] down_write_nested+0x60/0xa0 kernel/locking/rwsem.c:174
[<ffffffff815af1d1>] inode_lock_nested include/linux/fs.h:801 [inline]
[<ffffffff815af1d1>] do_unlinkat+0x2a1/0x680 fs/namei.c:4067
[<ffffffff815b10ea>] SYSC_unlink fs/namei.c:4128 [inline]
[<ffffffff815b10ea>] SyS_unlink+0x1a/0x20 fs/namei.c:4126
[<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
[<ffffffff83a019d3>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Showing all locks held in the system:
2 locks held by khungtaskd/519:
#0: (rcu_read_lock){......}, at: [<ffffffff813689dc>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
#0: (rcu_read_lock){......}, at: [<ffffffff813689dc>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
#1: (tasklist_lock){.+.+..}, at: [<ffffffff81428248>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/3772:
#0: (&tty->ldisc_sem){++++++}, at: [<ffffffff839ffba2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
#1: (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff82125402>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
2 locks held by syz-executor0/12023:
#0: (sb_writers#16){.+.+.+}, at: [<ffffffff815e50cf>] sb_start_write include/linux/fs.h:1573 [inline]
#0: (sb_writers#16){.+.+.+}, at: [<ffffffff815e50cf>] mnt_want_write+0x3f/0xb0 fs/namespace.c:391
#1: (&sb->s_type->i_mutex_key#23/1){+.+.+.}, at: [<ffffffff815ae7aa>] inode_lock_nested include/linux/fs.h:801 [inline]
#1: (&sb->s_type->i_mutex_key#23/1){+.+.+.}, at: [<ffffffff815ae7aa>] filename_create+0x17a/0x490 fs/namei.c:3639
2 locks held by syz-executor0/12037:
#0: (sb_writers#16){.+.+.+}, at: [<ffffffff815e50cf>] sb_start_write include/linux/fs.h:1573 [inline]
#0: (sb_writers#16){.+.+.+}, at: [<ffffffff815e50cf>] mnt_want_write+0x3f/0xb0 fs/namespace.c:391
#1: (&sb->s_type->i_mutex_key#23/1){+.+.+.}, at: [<ffffffff815af1d1>] inode_lock_nested include/linux/fs.h:801 [inline]
#1: (&sb->s_type->i_mutex_key#23/1){+.+.+.}, at: [<ffffffff815af1d1>] do_unlinkat+0x2a1/0x680 fs/namei.c:4067
2 locks held by syz-executor0/12093:
#0: (sb_writers#16){.+.+.+}, at: [<ffffffff815e50cf>] sb_start_write include/linux/fs.h:1573 [inline]
#0: (sb_writers#16){.+.+.+}, at: [<ffffffff815e50cf>] mnt_want_write+0x3f/0xb0 fs/namespace.c:391
#1: (&sb->s_type->i_mutex_key#23/1){+.+.+.}, at: [<ffffffff815ae7aa>] inode_lock_nested include/linux/fs.h:801 [inline]
#1: (&sb->s_type->i_mutex_key#23/1){+.+.+.}, at: [<ffffffff815ae7aa>] filename_create+0x17a/0x490 fs/namei.c:3639
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 519 Comm: khungtaskd Not tainted 4.9.124-g09eb2ba #31
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
ffff8801d9277d08 ffffffff81eb95e9 0000000000000000 0000000000000000
0000000000000000 0000000000000001 ffffffff810b9fa0 ffff8801d9277d40
ffffffff81ec4927 0000000000000000 0000000000000000 0000000000000003
Call Trace:
[<ffffffff81eb95e9>] __dump_stack lib/dump_stack.c:15 [inline]
[<ffffffff81eb95e9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
[<ffffffff81ec4927>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
[<ffffffff81ec48ba>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
[<ffffffff810ba0a4>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
[<ffffffff81368f74>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
[<ffffffff81368f74>] check_hung_task kernel/hung_task.c:125 [inline]
[<ffffffff81368f74>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
[<ffffffff81368f74>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
[<ffffffff8119f3cd>] kthread+0x26d/0x300 kernel/kthread.c:211
[<ffffffff83a01b9c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff83a00606