[QUESTION] Hung task warning while running syzkaller test
From: Zhihao Cheng
Date: Mon Oct 14 2019 - 03:03:18 EST
Hi, everyone. We met a hung task problem while running syzkaller test. The stacks of hung tasks vary in net/fs/sched, and we provide a stable reproduce test case in fs. The higher the kernel version, the lower the probability of reproduce. Maybe the mainline has gradually optimized the scheduling and mutex.
Environment:
A. qemu(x86_64 8-core 16GB-RAM)
B. physical machine (x86_64 8-core 314GB-RAM)
./syz-execprog -executor=/home/abc/syz-executor -repeat=0 -procs=16 -cover=0 repro
repro is a configuration file containing syzkaller execution instructions, which shown as follows:
syz_execute_func(&(0x7f0000000140)="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")
socket(0x1, 0x80000, 0x4)
Hung task in kernel-4.4(See full message in hung_task_verbose.log):
[ 420.762345] INFO: task syz-executor.1:8244 blocked for more than 140 seconds.
[ 420.763691] Not tainted 4.4.186-514.55.6.9.x86_64 #1
[ 420.764645] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 420.765931] syz-executor.1 D ffff88040e6efc80 13728 8244 8242 0x00000000
[ 420.767189] ffff88040e6efc80 ffff88040e71c990 ffff880400000000 ffff880077df3d80
[ 420.768497] ffff88040e71bd80 ffff88040e6f0000 0000000000000246 ffff88041f5007c0
[ 420.769800] ffff88040e71bd80 00000000ffffffff ffff88040e6efc98 ffffffff818c6ebc
[ 420.771109] Call Trace:
[ 420.771540] [<ffffffff818c6ebc>] schedule+0x3c/0x90
[ 420.772369] [<ffffffff818c72a5>] schedule_preempt_disabled+0x15/0x20
[ 420.773437] [<ffffffff818c9692>] mutex_lock_nested+0x182/0x500
[ 420.774421] [<ffffffff81252fdf>] ? walk_component+0x21f/0x310
[ 420.775396] [<ffffffff8124fb4a>] ? __inode_permission+0x3a/0x80
[ 420.776391] [<ffffffff81252fdf>] walk_component+0x21f/0x310
[ 420.777333] [<ffffffff81253f3b>] ? path_lookupat+0x1b/0x110
[ 420.778273] [<ffffffff81253f7d>] path_lookupat+0x5d/0x110
[ 420.779197] [<ffffffff81255bc1>] filename_lookup+0xb1/0x180
[ 420.780130] [<ffffffff811133dd>] ? rcu_read_lock_sched_held+0x6d/0x80
[ 420.781211] [<ffffffff81228db0>] ? kmem_cache_alloc+0x240/0x2b0
[ 420.782212] [<ffffffff811132ed>] ? debug_lockdep_rcu_enabled+0x1d/0x20
[ 420.783312] [<ffffffff81255d66>] user_path_at_empty+0x36/0x40
[ 420.784284] [<ffffffff8126fcd3>] path_removexattr+0x43/0xb0
[ 420.785229] [<ffffffff81003044>] ? lockdep_sys_exit_thunk+0x12/0x14
[ 420.786283] [<ffffffff81270c50>] SyS_lremovexattr+0x10/0x20
[ 420.787232] [<ffffffff818cdda1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
[ 420.788302] 1 lock held by syz-executor.1/8244:
[ 420.789051] #0: (&sb->s_type->i_mutex_key#2){+.+.+.}, at: [<ffffffff81252fdf>] walk_component+0x21f/0x310
Hung task in kernel-5.3-rc6:
[30391.827102] INFO: task syz-executor.6:12211 blocked for more than 143 seconds.
[30391.827194] Not tainted 5.3.0-rc6-514.55.6.9.x86_64 #41
[30391.827214] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[30391.827239] syz-executor.6 D13904 12211 12143 0x00000000
[30391.827319] Call Trace:
[30391.828583] ? __schedule+0x3cc/0x8b0
[30391.828669] schedule+0x30/0xb0
[30391.828785] rwsem_down_write_slowpath+0x2d2/0x730
[30391.829039] ? filename_create+0x9d/0x1d0
[30391.829110] ? filename_create+0x9d/0x1d0
[30391.829136] ? rwsem_down_write_slowpath+0x5/0x730
[30391.829163] filename_create+0x9d/0x1d0
[30391.829247] do_mkdirat+0x54/0x120
[30391.829361] do_syscall_64+0x85/0x380
[30391.829445] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[30391.829509] RIP: 0033:0x20000148
[30391.829562] Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f2 aa 98 44 13 e8 0f 05 <95> 32 05 83 00 00 00 71 f3 2e f3 0f 1b 6f 00 2e 67 66 66 44 0f 38
[30391.829604] RSP: 002b:00007fd154213bd8 EFLAGS: 00000203 ORIG_RAX: 0000000000000053
[30391.829638] RAX: ffffffffffffffda RBX: 0000000000000009 RCX: 0000000020000148
[30391.829659] RDX: da194cf4f57fa1d4 RSI: 0000000000000000 RDI: 00007fd15421460a
[30391.829680] RBP: 0000000000000045 R08: 0000000000000005 R09: 0000000000000006
[30391.829703] R10: 0000000000000007 R11: 0000000000000203 R12: 000000000000000b
[30391.829724] R13: 000000000000014c R14: 000000000000000d R15: 00000000ffffffff
Intro of attachments:
hung_task_verbose.log: verbose of hung task(with lockdep)
repro: reproduction file which contains syzkaller execution instructions
Any ideas or suggestions? Thanks a lot.
[ 420.762345] INFO: task syz-executor.1:8244 blocked for more than 140 seconds.
[ 420.763691] Not tainted 4.4.186-514.55.6.9.x86_64 #1
[ 420.764645] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 420.765931] syz-executor.1 D ffff88040e6efc80 13728 8244 8242 0x00000000
[ 420.767189] ffff88040e6efc80 ffff88040e71c990 ffff880400000000 ffff880077df3d80
[ 420.768497] ffff88040e71bd80 ffff88040e6f0000 0000000000000246 ffff88041f5007c0
[ 420.769800] ffff88040e71bd80 00000000ffffffff ffff88040e6efc98 ffffffff818c6ebc
[ 420.771109] Call Trace:
[ 420.771540] [<ffffffff818c6ebc>] schedule+0x3c/0x90
[ 420.772369] [<ffffffff818c72a5>] schedule_preempt_disabled+0x15/0x20
[ 420.773437] [<ffffffff818c9692>] mutex_lock_nested+0x182/0x500
[ 420.774421] [<ffffffff81252fdf>] ? walk_component+0x21f/0x310
[ 420.775396] [<ffffffff8124fb4a>] ? __inode_permission+0x3a/0x80
[ 420.776391] [<ffffffff81252fdf>] walk_component+0x21f/0x310
[ 420.777333] [<ffffffff81253f3b>] ? path_lookupat+0x1b/0x110
[ 420.778273] [<ffffffff81253f7d>] path_lookupat+0x5d/0x110
[ 420.779197] [<ffffffff81255bc1>] filename_lookup+0xb1/0x180
[ 420.780130] [<ffffffff811133dd>] ? rcu_read_lock_sched_held+0x6d/0x80
[ 420.781211] [<ffffffff81228db0>] ? kmem_cache_alloc+0x240/0x2b0
[ 420.782212] [<ffffffff811132ed>] ? debug_lockdep_rcu_enabled+0x1d/0x20
[ 420.783312] [<ffffffff81255d66>] user_path_at_empty+0x36/0x40
[ 420.784284] [<ffffffff8126fcd3>] path_removexattr+0x43/0xb0
[ 420.785229] [<ffffffff81003044>] ? lockdep_sys_exit_thunk+0x12/0x14
[ 420.786283] [<ffffffff81270c50>] SyS_lremovexattr+0x10/0x20
[ 420.787232] [<ffffffff818cdda1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
[ 420.788302] 1 lock held by syz-executor.1/8244:
[ 420.789051] #0: (&sb->s_type->i_mutex_key#2){+.+.+.}, at: [<ffffffff81252fdf>] walk_component+0x21f/0x310
[ 420.790815] INFO: task syz-executor.1:8735 blocked for more than 140 seconds.
[ 420.791990] Not tainted 4.4.186-514.55.6.9.x86_64 #1
[ 420.792901] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 420.794184] syz-executor.1 D ffff88040b047c30 13856 8735 8729 0x00000000
[ 420.795398] ffff88040b047c30 ffff88040b7caad0 ffff880400000000 ffff88040a570000
[ 420.796698] ffff88040b7c9ec0 ffff88040b048000 0000000000000246 ffff88041f5007c0
[ 420.798003] ffff88040b7c9ec0 00000000ffffffff ffff88040b047c48 ffffffff818c6ebc
[ 420.799320] Call Trace:
[ 420.799731] [<ffffffff818c6ebc>] schedule+0x3c/0x90
[ 420.800555] [<ffffffff818c72a5>] schedule_preempt_disabled+0x15/0x20
[ 420.801614] [<ffffffff818c9692>] mutex_lock_nested+0x182/0x500
[ 420.802603] [<ffffffff81252fdf>] ? walk_component+0x21f/0x310
[ 420.803566] [<ffffffff8124fb4a>] ? __inode_permission+0x3a/0x80
[ 420.804556] [<ffffffff81252fdf>] walk_component+0x21f/0x310
[ 420.805493] [<ffffffff81253f3b>] ? path_lookupat+0x1b/0x110
[ 420.806431] [<ffffffff81253f7d>] path_lookupat+0x5d/0x110
[ 420.807349] [<ffffffff81255bc1>] filename_lookup+0xb1/0x180
[ 420.808288] [<ffffffff811133dd>] ? rcu_read_lock_sched_held+0x6d/0x80
[ 420.809364] [<ffffffff81228db0>] ? kmem_cache_alloc+0x240/0x2b0
[ 420.810353] [<ffffffff81255d66>] user_path_at_empty+0x36/0x40
[ 420.811331] [<ffffffff8127e925>] do_utimes+0x115/0x160
[ 420.812202] [<ffffffff8127ea0b>] SyS_utime+0x9b/0xd0
[ 420.813034] [<ffffffff81003044>] ? lockdep_sys_exit_thunk+0x12/0x14
[ 420.814081] [<ffffffff818cdda1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
[ 420.815149] 1 lock held by syz-executor.1/8735:
[ 420.815903] #0: (&sb->s_type->i_mutex_key#2){+.+.+.}, at: [<ffffffff81252fdf>] walk_component+0x21f/0x310
[ 420.817647] INFO: task syz-executor.1:8795 blocked for more than 140 seconds.
[ 420.818828] Not tainted 4.4.186-514.55.6.9.x86_64 #1
[ 420.819736] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 420.821016] syz-executor.1 D ffff88040ad6fc80 13952 8795 8791 0x00000000
[ 420.822233] ffff88040ad6fc80 ffff88040acc2ad0 ffff880400000000 ffff88040ac30000
[ 420.823539] ffff88040acc1ec0 ffff88040ad70000 0000000000000246 ffff88041f5007c0
[ 420.824840] ffff88040acc1ec0 00000000ffffffff ffff88040ad6fc98 ffffffff818c6ebc
[ 420.826138] Call Trace:
[ 420.826565] [<ffffffff818c6ebc>] schedule+0x3c/0x90
[ 420.827392] [<ffffffff818c72a5>] schedule_preempt_disabled+0x15/0x20
[ 420.828454] [<ffffffff818c9692>] mutex_lock_nested+0x182/0x500
[ 420.829433] [<ffffffff81252fdf>] ? walk_component+0x21f/0x310
[ 420.830400] [<ffffffff8124fb4a>] ? __inode_permission+0x3a/0x80
[ 420.831402] [<ffffffff81252fdf>] walk_component+0x21f/0x310
[ 420.832341] [<ffffffff81253f3b>] ? path_lookupat+0x1b/0x110
[ 420.833278] [<ffffffff81253f7d>] path_lookupat+0x5d/0x110
[ 420.834191] [<ffffffff81255bc1>] filename_lookup+0xb1/0x180
[ 420.835127] [<ffffffff811133dd>] ? rcu_read_lock_sched_held+0x6d/0x80
[ 420.836201] [<ffffffff81228db0>] ? kmem_cache_alloc+0x240/0x2b0
[ 420.837196] [<ffffffff811132ed>] ? debug_lockdep_rcu_enabled+0x1d/0x20
[ 420.838287] [<ffffffff81255d66>] user_path_at_empty+0x36/0x40
[ 420.839261] [<ffffffff8126fcd3>] path_removexattr+0x43/0xb0
[ 420.840199] [<ffffffff81003044>] ? lockdep_sys_exit_thunk+0x12/0x14
[ 420.841246] [<ffffffff81270c50>] SyS_lremovexattr+0x10/0x20
[ 420.842186] [<ffffffff818cdda1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
[ 420.843256] 1 lock held by syz-executor.1/8795:
[ 420.844001] #0: (&sb->s_type->i_mutex_key#2){+.+.+.}, at: [<ffffffff81252fdf>] walk_component+0x21f/0x310
[ 420.845766] INFO: task syz-executor.1:9075 blocked for more than 140 seconds.
[ 420.846948] Not tainted 4.4.186-514.55.6.9.x86_64 #1
[ 420.847855] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 420.849136] syz-executor.1 D ffff880409783df0 14176 9075 9073 0x00000000
[ 420.850352] ffff880409783df0 ffff8804094e8c10 ffff880400000000 ffff8803fe8c9ec0
[ 420.851662] ffff8804094e8000 ffff880409784000 0000000000000246 ffff88041f5007c0
[ 420.852962] ffff8804094e8000 00000000ffffffff ffff880409783e08 ffffffff818c6ebc
[ 420.854272] Call Trace:
[ 420.854691] [<ffffffff818c6ebc>] schedule+0x3c/0x90
[ 420.855517] [<ffffffff818c72a5>] schedule_preempt_disabled+0x15/0x20
[ 420.856578] [<ffffffff818c9692>] mutex_lock_nested+0x182/0x500
[ 420.857555] [<ffffffff81255f7f>] ? filename_create+0x7f/0x170
[ 420.858524] [<ffffffff810f0b9c>] ? percpu_down_read+0x5c/0xa0
[ 420.859501] [<ffffffff81255f7f>] filename_create+0x7f/0x170
[ 420.860440] [<ffffffff81256ed1>] SyS_mkdir+0x51/0xe0
[ 420.861279] [<ffffffff818cdda1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
[ 420.862342] 2 locks held by syz-executor.1/9075:
[ 420.863109] #0: (sb_writers#2){.+.+.+}, at: [<ffffffff81247e97>] __sb_start_write+0xb7/0xf0
[ 420.864642] #1: (&sb->s_type->i_mutex_key#2/1){+.+.+.}, at: [<ffffffff81255f7f>] filename_create+0x7f/0x170
[ 431.979231] INFO: task syz-executor.1:9569 blocked for more than 140 seconds.
[ 431.980483] Not tainted 4.4.186-514.55.6.9.x86_64 #1
[ 431.981429] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 431.982754] syz-executor.1 D ffff8804064d7c30 14272 9569 7814 0x00000000
[ 431.983969] ffff8804064d7c30 ffff88040687c990 ffff880400000000 ffff880406c43d80
[ 431.985281] ffff88040687bd80 ffff8804064d8000 0000000000000246 ffff88041f5007c0
[ 431.986596] ffff88040687bd80 00000000ffffffff ffff8804064d7c48 ffffffff818c6ebc
[ 431.987898] Call Trace:
[ 431.988329] [<ffffffff818c6ebc>] schedule+0x3c/0x90
[ 431.989149] [<ffffffff818c72a5>] schedule_preempt_disabled+0x15/0x20
[ 431.990210] [<ffffffff818c9692>] mutex_lock_nested+0x182/0x500
[ 431.991203] [<ffffffff81252fdf>] ? walk_component+0x21f/0x310
[ 431.992177] [<ffffffff8124fb4a>] ? __inode_permission+0x3a/0x80
[ 431.993183] [<ffffffff81252fdf>] walk_component+0x21f/0x310
[ 431.994116] [<ffffffff81253f3b>] ? path_lookupat+0x1b/0x110
[ 431.995064] [<ffffffff81253f7d>] path_lookupat+0x5d/0x110
[ 431.995977] [<ffffffff81255bc1>] filename_lookup+0xb1/0x180
[ 431.996922] [<ffffffff811133dd>] ? rcu_read_lock_sched_held+0x6d/0x80
[ 431.998001] [<ffffffff81228db0>] ? kmem_cache_alloc+0x240/0x2b0
[ 431.999005] [<ffffffff81255d66>] user_path_at_empty+0x36/0x40
[ 431.999974] [<ffffffff8127e925>] do_utimes+0x115/0x160
[ 432.000842] [<ffffffff8127ea0b>] SyS_utime+0x9b/0xd0
[ 432.001687] [<ffffffff81003044>] ? lockdep_sys_exit_thunk+0x12/0x14
[ 432.002751] [<ffffffff818cdda1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
[ 432.003819] 1 lock held by syz-executor.1/9569:
[ 432.004577] #0: (&sb->s_type->i_mutex_key#2){+.+.+.}, at: [<ffffffff81252fdf>] walk_component+0x21f/0x310
[ 432.006328] INFO: task syz-executor.1:9810 blocked for more than 140 seconds.
[ 432.007516] Not tainted 4.4.186-514.55.6.9.x86_64 #1
[ 432.008428] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 432.009720] syz-executor.1 D ffff88040523bc80 13952 9810 9808 0x00000000
[ 432.010950] ffff88040523bc80 ffff880405230c10 ffff880400000000 ffff880404c43d80
[ 432.012265] ffff880405230000 ffff88040523c000 0000000000000246 ffff88041f5007c0
[ 432.013574] ffff880405230000 00000000ffffffff ffff88040523bc98 ffffffff818c6ebc
[ 432.014886] Call Trace:
[ 432.015310] [<ffffffff818c6ebc>] schedule+0x3c/0x90
[ 432.016131] [<ffffffff818c72a5>] schedule_preempt_disabled+0x15/0x20
[ 432.017195] [<ffffffff818c9692>] mutex_lock_nested+0x182/0x500
[ 432.018182] [<ffffffff81252fdf>] ? walk_component+0x21f/0x310
[ 432.019149] [<ffffffff8124fb4a>] ? __inode_permission+0x3a/0x80
[ 432.020140] [<ffffffff81252fdf>] walk_component+0x21f/0x310
[ 432.021079] [<ffffffff81253f3b>] ? path_lookupat+0x1b/0x110
[ 432.022017] [<ffffffff81253f7d>] path_lookupat+0x5d/0x110
[ 432.022941] [<ffffffff81255bc1>] filename_lookup+0xb1/0x180
[ 432.023880] [<ffffffff811133dd>] ? rcu_read_lock_sched_held+0x6d/0x80
[ 432.024959] [<ffffffff81228db0>] ? kmem_cache_alloc+0x240/0x2b0
[ 432.025953] [<ffffffff811132ed>] ? debug_lockdep_rcu_enabled+0x1d/0x20
[ 432.027049] [<ffffffff81255d66>] user_path_at_empty+0x36/0x40
[ 432.028016] [<ffffffff8126fcd3>] path_removexattr+0x43/0xb0
[ 432.028953] [<ffffffff81003044>] ? lockdep_sys_exit_thunk+0x12/0x14
[ 432.030003] [<ffffffff81270c50>] SyS_lremovexattr+0x10/0x20
[ 432.030949] [<ffffffff818cdda1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
[ 432.032011] 1 lock held by syz-executor.1/9810:
[ 432.032767] #0: (&sb->s_type->i_mutex_key#2){+.+.+.}, at: [<ffffffff81252fdf>] walk_component+0x21f/0x310
[ 432.034509] INFO: task syz-executor.1:9826 blocked for more than 140 seconds.
[ 432.035690] Not tainted 4.4.186-514.55.6.9.x86_64 #1
[ 432.036606] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 432.037895] syz-executor.1 D ffff8804053cfc80 13856 9826 9816 0x00000000
[ 432.039113] ffff8804053cfc80 ffff88040539c990 ffff880400000000 ffff88040513dc40
[ 432.040427] ffff88040539bd80 ffff8804053d0000 0000000000000246 ffff88041f5007c0
[ 432.041730] ffff88040539bd80 00000000ffffffff ffff8804053cfc98 ffffffff818c6ebc
[ 432.043035] Call Trace:
[ 432.043459] [<ffffffff818c6ebc>] schedule+0x3c/0x90
[ 432.044287] [<ffffffff818c72a5>] schedule_preempt_disabled+0x15/0x20
[ 432.045355] [<ffffffff818c9692>] mutex_lock_nested+0x182/0x500
[ 432.046339] [<ffffffff81252fdf>] ? walk_component+0x21f/0x310
[ 432.047343] [<ffffffff8124fb4a>] ? __inode_permission+0x3a/0x80
[ 432.048338] [<ffffffff81252fdf>] walk_component+0x21f/0x310
[ 432.049278] [<ffffffff81253f3b>] ? path_lookupat+0x1b/0x110
[ 432.050218] [<ffffffff81253f7d>] path_lookupat+0x5d/0x110
[ 432.051132] [<ffffffff81255bc1>] filename_lookup+0xb1/0x180
[ 432.052071] [<ffffffff811133dd>] ? rcu_read_lock_sched_held+0x6d/0x80
[ 432.053148] [<ffffffff81228db0>] ? kmem_cache_alloc+0x240/0x2b0
[ 432.054139] [<ffffffff811132ed>] ? debug_lockdep_rcu_enabled+0x1d/0x20
[ 432.055233] [<ffffffff81255d66>] user_path_at_empty+0x36/0x40
[ 432.056201] [<ffffffff8126fcd3>] path_removexattr+0x43/0xb0
[ 432.057133] [<ffffffff81003044>] ? lockdep_sys_exit_thunk+0x12/0x14
[ 432.058178] [<ffffffff81270c50>] SyS_lremovexattr+0x10/0x20
[ 432.059114] [<ffffffff818cdda1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
[ 432.060175] 1 lock held by syz-executor.1/9826:
[ 432.060922] #0: (&sb->s_type->i_mutex_key#2){+.+.+.}, at: [<ffffffff81252fdf>] walk_component+0x21f/0x310
[ 432.062672] INFO: task syz-executor.1:9902 blocked for more than 140 seconds.
[ 432.063852] Not tainted 4.4.186-514.55.6.9.x86_64 #1
[ 432.064762] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 432.066049] syz-executor.1 D ffff880404417c70 13856 9902 9862 0x00000000
[ 432.067280] ffff880404417c70 ffff880404aec990 ffff880400000000 ffff88040533bd80
[ 432.068587] ffff880404aebd80 ffff880404418000 0000000000000246 ffff88041f5007c0
[ 432.069890] ffff880404aebd80 00000000ffffffff ffff880404417c88 ffffffff818c6ebc
[ 432.071243] Call Trace:
[ 432.071656] [<ffffffff818c6ebc>] schedule+0x3c/0x90
[ 432.072483] [<ffffffff818c72a5>] schedule_preempt_disabled+0x15/0x20
[ 432.073546] [<ffffffff818c9692>] mutex_lock_nested+0x182/0x500
[ 432.074534] [<ffffffff81252fdf>] ? walk_component+0x21f/0x310
[ 432.075505] [<ffffffff8124fb4a>] ? __inode_permission+0x3a/0x80
[ 432.076502] [<ffffffff81252fdf>] walk_component+0x21f/0x310
[ 432.077446] [<ffffffff81253f3b>] ? path_lookupat+0x1b/0x110
[ 432.078391] [<ffffffff81253f7d>] path_lookupat+0x5d/0x110
[ 432.079314] [<ffffffff81255bc1>] filename_lookup+0xb1/0x180
[ 432.080260] [<ffffffff811133dd>] ? rcu_read_lock_sched_held+0x6d/0x80
[ 432.081348] [<ffffffff81228db0>] ? kmem_cache_alloc+0x240/0x2b0
[ 432.082351] [<ffffffff81255d66>] user_path_at_empty+0x36/0x40
[ 432.083331] [<ffffffff8127021b>] path_getxattr+0x4b/0xb0
[ 432.084234] [<ffffffff81003044>] ? lockdep_sys_exit_thunk+0x12/0x14
[ 432.085291] [<ffffffff81270ab1>] SyS_lgetxattr+0x11/0x20
[ 432.086195] [<ffffffff818cdda1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
[ 432.087273] 1 lock held by syz-executor.1/9902:
[ 432.088025] #0: (&sb->s_type->i_mutex_key#2){+.+.+.}, at: [<ffffffff81252fdf>] walk_component+0x21f/0x310
[ 445.381195] INFO: task syz-executor.1:9914 blocked for more than 140 seconds.
[ 445.382485] Not tainted 4.4.186-514.55.6.9.x86_64 #1
[ 445.383408] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 445.384705] syz-executor.1 D ffff880404df7c80 13856 9914 9907 0x00000000
[ 445.385931] ffff880404df7c80 ffff880404e18c10 ffff880400000000 ffff8804059d0000
[ 445.387264] ffff880404e18000 ffff880404df8000 0000000000000246 ffff88041f5007c0
[ 445.388582] ffff880404e18000 00000000ffffffff ffff880404df7c98 ffffffff818c6ebc
[ 445.389896] Call Trace:
[ 445.390327] [<ffffffff818c6ebc>] schedule+0x3c/0x90
[ 445.391157] [<ffffffff818c72a5>] schedule_preempt_disabled+0x15/0x20
[ 445.392229] [<ffffffff818c9692>] mutex_lock_nested+0x182/0x500
[ 445.393226] [<ffffffff81252fdf>] ? walk_component+0x21f/0x310
[ 445.394203] [<ffffffff8124fb4a>] ? __inode_permission+0x3a/0x80
[ 445.395219] [<ffffffff81252fdf>] walk_component+0x21f/0x310
[ 445.396157] [<ffffffff81253f3b>] ? path_lookupat+0x1b/0x110
[ 445.397100] [<ffffffff81253f7d>] path_lookupat+0x5d/0x110
[ 445.398017] [<ffffffff81255bc1>] filename_lookup+0xb1/0x180
[ 445.398971] [<ffffffff811133dd>] ? rcu_read_lock_sched_held+0x6d/0x80
[ 445.400059] [<ffffffff81228db0>] ? kmem_cache_alloc+0x240/0x2b0
[ 445.401060] [<ffffffff811132ed>] ? debug_lockdep_rcu_enabled+0x1d/0x20
[ 445.402159] [<ffffffff81255d66>] user_path_at_empty+0x36/0x40
[ 445.403139] [<ffffffff8126fcd3>] path_removexattr+0x43/0xb0
[ 445.404085] [<ffffffff81003044>] ? lockdep_sys_exit_thunk+0x12/0x14
[ 445.405138] [<ffffffff81270c50>] SyS_lremovexattr+0x10/0x20
[ 445.406081] [<ffffffff818cdda1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
[ 445.407160] 1 lock held by syz-executor.1/9914:
[ 445.407932] #0: (&sb->s_type->i_mutex_key#2){+.+.+.}, at: [<ffffffff81252fdf>] walk_component+0x21f/0x310
[ 445.409681] INFO: task syz-executor.1:9921 blocked for more than 140 seconds.
[ 445.410870] Not tainted 4.4.186-514.55.6.9.x86_64 #1
[ 445.411786] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 445.413080] syz-executor.1 D ffff880404473c30 14208 9921 9902 0x00000000
[ 445.414306] ffff880404473c30 ffff880404b96850 ffff880400000000 ffff880405339ec0
[ 445.415624] ffff880404b95c40 ffff880404474000 0000000000000246 ffff88041f5007c0
[ 445.416934] ffff880404b95c40 00000000ffffffff ffff880404473c48 ffffffff818c6ebc
[ 445.418258] Call Trace:
[ 445.418681] [<ffffffff818c6ebc>] schedule+0x3c/0x90
[ 445.419513] [<ffffffff818c72a5>] schedule_preempt_disabled+0x15/0x20
[ 445.420583] [<ffffffff818c9692>] mutex_lock_nested+0x182/0x500
[ 445.421569] [<ffffffff81252fdf>] ? walk_component+0x21f/0x310
[ 445.422544] [<ffffffff8124fb4a>] ? __inode_permission+0x3a/0x80
[ 445.423548] [<ffffffff81252fdf>] walk_component+0x21f/0x310
[ 445.424498] [<ffffffff81253f3b>] ? path_lookupat+0x1b/0x110
[ 445.425442] [<ffffffff81253f7d>] path_lookupat+0x5d/0x110
[ 445.426360] [<ffffffff81255bc1>] filename_lookup+0xb1/0x180
[ 445.427314] [<ffffffff811133dd>] ? rcu_read_lock_sched_held+0x6d/0x80
[ 445.428400] [<ffffffff81228db0>] ? kmem_cache_alloc+0x240/0x2b0
[ 445.429401] [<ffffffff81255d66>] user_path_at_empty+0x36/0x40
[ 445.430379] [<ffffffff8127e925>] do_utimes+0x115/0x160
[ 445.431260] [<ffffffff8127ea0b>] SyS_utime+0x9b/0xd0
[ 445.432098] [<ffffffff81003044>] ? lockdep_sys_exit_thunk+0x12/0x14
[ 445.433155] [<ffffffff818cdda1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
[ 445.434227] 1 lock held by syz-executor.1/9921:
[ 445.434985] #0: (&sb->s_type->i_mutex_key#2){+.+.+.}, at: [<ffffffff81252fdf>] walk_component+0x21f/0x310syz_execute_func(&(0x7f0000000140)="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")
socket(0x1, 0x80000, 0x4)