syzbot


INFO: task hung in seq_free_client

Status: auto-closed as invalid on 2019/02/23 15:39
First crash: 2162d, last: 2056d
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in seq_free_client sound 1 2075d 2075d 0/26 closed as invalid on 2018/09/05 12:51

Sample crash report:
IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready
IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready
IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready
INFO: task syz-executor6:5026 blocked for more than 140 seconds.
      Not tainted 4.9.124-g09eb2ba #83
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor6   D29624  5026   3758 0x00000004
 ffff880194aa6000 ffff8801d90f9a40 ffff8801d90f9a40 ffff8801cfc39800
 ffff8801db321c18 ffff8801a5637c78 ffffffff839f0afd ffff880194aa68c8
 ffffed0032954d18 ffff880194aa6000 00fffc0000000000 ffff8801db3224e8
Call Trace:
 [<ffffffff839f20ff>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff839f2a83>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3586
 [<ffffffff839f6f06>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff839f6f06>] mutex_lock_nested+0x326/0x870 kernel/locking/mutex.c:621
 [<ffffffff82f53d4f>] seq_free_client+0x1f/0xf0 sound/core/seq/seq_clientmgr.c:277
 [<ffffffff82f53f11>] snd_seq_release+0x51/0xe0 sound/core/seq/seq_clientmgr.c:367
 [<ffffffff8157ca73>] __fput+0x263/0x700 fs/file_table.c:208
 [<ffffffff8157cf95>] ____fput+0x15/0x20 fs/file_table.c:244
 [<ffffffff8119a66c>] task_work_run+0x10c/0x180 kernel/task_work.c:116
 [<ffffffff8100559c>] tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 [<ffffffff8100559c>] exit_to_usermode_loop+0xfc/0x120 arch/x86/entry/common.c:161
 [<ffffffff810064d4>] prepare_exit_to_usermode arch/x86/entry/common.c:191 [inline]
 [<ffffffff810064d4>] syscall_return_slowpath arch/x86/entry/common.c:260 [inline]
 [<ffffffff810064d4>] do_syscall_64+0x364/0x490 arch/x86/entry/common.c:287
 [<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
1 lock held by rsyslogd/3539:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815dc7ec>] __fdget_pos+0xac/0xd0 fs/file.c:781
2 locks held by getty/3637:
 #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
1 lock held by syz-executor6/5026:
 #0:  (register_mutex#3){+.+.+.}, at: [<ffffffff82f53d4f>] seq_free_client+0x1f/0xf0 sound/core/seq/seq_clientmgr.c:277
1 lock held by syz-executor5/5048:
 #0:  (register_mutex#3){+.+.+.}, at: [<ffffffff82f53d4f>] seq_free_client+0x1f/0xf0 sound/core/seq/seq_clientmgr.c:277

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 519 Comm: khungtaskd Not tainted 4.9.124-g09eb2ba #83
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d8877d08 ffffffff81eb95e9 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810b9fa0 ffff8801d8877d40
 ffffffff81ec4927 0000000000000001 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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.9.124-g09eb2ba #83
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffffffff84629800 task.stack: ffffffff84600000
RIP: 0010:[<ffffffff81ecae4e>] c [<ffffffff81ecae4e>] rb_set_parent_color include/linux/rbtree_augmented.h:117 [inline]
RIP: 0010:[<ffffffff81ecae4e>] c [<ffffffff81ecae4e>] __rb_insert lib/rbtree.c:134 [inline]
RIP: 0010:[<ffffffff81ecae4e>] c [<ffffffff81ecae4e>] rb_insert_color+0x5de/0xca0 lib/rbtree.c:420
RSP: 0018:ffff8801db207a78  EFLAGS: 00000046
RAX: ffff8801d96c6090 RBX: ffff8801c6d81890 RCX: ffff8801c6d81890
RDX: 1ffff10038db0313 RSI: ffff8801db221cc8 RDI: ffff8801d4018090
RBP: ffff8801db207ab8 R08: ffff8801d40180d0 R09: ffff8801d96c6090
R10: 000000000000017c R11: 0000000000000000 R12: ffff8801d96c6090
R13: ffff8801c6d81891 R14: ffff8801ce28e090 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdd67b66000 CR3: 00000001cc366000 CR4: 00000000001606f0
Stack:
 ffff8801d4018080c ffff8801db207b18c ffffffff811ee1a5c ffff8801d4018090c
 ffff8801d96c6098c dffffc0000000000c ffff8801d4018080c ffffed003a80301ac
 ffff8801db207b18c ffffffff811e4fd8c ffff8801d40180a8c ffff8801db2225a0c
Call Trace:
 [<ffffffff811e4fd8>] __enqueue_entity+0x138/0x230 kernel/sched/fair.c:581
 [<ffffffff811f215a>] enqueue_entity kernel/sched/fair.c:3659 [inline]
 [<ffffffff811f215a>] enqueue_task_fair+0x24a/0x2680 kernel/sched/fair.c:4823
 [<ffffffff811ccd23>] enqueue_task kernel/sched/core.c:774 [inline]
 [<ffffffff811ccd23>] activate_task+0x153/0x280 kernel/sched/core.c:790
 [<ffffffff811cdde5>] ttwu_activate kernel/sched/core.c:1702 [inline]
 [<ffffffff811cdde5>] ttwu_do_activate+0xd5/0x200 kernel/sched/core.c:1761
 [<ffffffff811d1160>] ttwu_queue kernel/sched/core.c:1917 [inline]
 [<ffffffff811d1160>] try_to_wake_up+0x760/0xec0 kernel/sched/core.c:2130
 [<ffffffff811d18d0>] wake_up_process+0x10/0x20 kernel/sched/core.c:2205
 [<ffffffff8129aad5>] process_timeout+0x15/0x20 kernel/time/timer.c:1724
 [<ffffffff8129ac43>] call_timer_fn+0x163/0x6e0 kernel/time/timer.c:1319
 [<ffffffff812a1da7>] expire_timers kernel/time/timer.c:1359 [inline]
 [<ffffffff812a1da7>] __run_timers kernel/time/timer.c:1658 [inline]
 [<ffffffff812a1da7>] run_timer_softirq+0x1047/0x1590 kernel/time/timer.c:1684
 [<ffffffff83a085c0>] __do_softirq+0x210/0x940 kernel/softirq.c:288
 [<ffffffff8114d554>] invoke_softirq kernel/softirq.c:368 [inline]
 [<ffffffff8114d554>] irq_exit+0x114/0x150 kernel/softirq.c:409
 [<ffffffff83a071a1>] exiting_irq arch/x86/include/asm/apic.h:669 [inline]
 [<ffffffff83a071a1>] smp_apic_timer_interrupt+0x81/0xa0 arch/x86/kernel/apic/apic.c:962
 [<ffffffff83a03330>] apic_timer_interrupt+0xa0/0xb0 arch/x86/entry/entry_64.S:648
 <EOI> d [<ffffffff83a00606>] ? native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:55
 [<ffffffff839ffc45>] arch_safe_halt arch/x86/include/asm/paravirt.h:104 [inline]
 [<ffffffff839ffc45>] default_idle+0x55/0x360 arch/x86/kernel/process.c:437
 [<ffffffff8106ae20>] arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:428
 [<ffffffff83a00a65>] default_idle_call+0x45/0x60 kernel/sched/idle.c:97
 [<ffffffff81225495>] cpuidle_idle_call kernel/sched/idle.c:155 [inline]
 [<ffffffff81225495>] cpu_idle_loop kernel/sched/idle.c:248 [inline]
 [<ffffffff81225495>] cpu_startup_entry+0x2b5/0x380 kernel/sched/idle.c:303
 [<ffffffff839ed8cc>] rest_init+0x183/0x189 init/main.c:409
 [<ffffffff84c98943>] start_kernel+0x67e/0x6b2 init/main.c:664
 [<ffffffff84c9729a>] x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:196
 [<ffffffff84c973db>] x86_64_start_kernel+0x13f/0x162 arch/x86/kernel/head64.c:177
Code: cf5 c05 c00 c00 c48 c89 c16 ce9 c4b cfc cff cff c4c c89 cf0 c49 c89 cdd c48 cc1 ce8 c03 c49 c83 ccd c01 c42 c80 c3c c38 c00 c0f c85 cd2 c04 c00 c00 c4c c89 ce0 c4d c89 c2e c<48> cc1 ce8 c03 c42 c80 c3c c38 c00 c0f c85 cf7 c04 c00 c00 c48 c89 cd8 c4d c89 c2c c

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/08/27 15:29 https://android.googlesource.com/kernel/common android-4.9 09eb2ba5ed0c 758cd203 .config console log report ci-android-49-kasan-gce
2018/05/13 17:48 https://android.googlesource.com/kernel/common android-4.9 c2f9bce9fee8 c05b619d .config console log report ci-android-49-kasan-gce
* Struck through repros no longer work on HEAD.