Re: 2.6.27-rc4-git1: Reported regressions from 2.6.26

Daniel J Blueman
2008-08-25T13:03:15Z

Hi Linus, Vegard,

On Sun, Aug 24, 2008 at 7:58 PM, Linus Torvalds
<torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org> wrote:
> On Sun, 24 Aug 2008, Vegard Nossum wrote:
[snip]
> Anyway, I think your patch is likely fine, I just thought it looked a bit
> odd to have a loop to move a list from one head pointer to another.
>
> But regardless, it would need some testing. Daniel?

This opens another lockdep report at boot-time [1] - promoting
pool_lock may not be the best fix?

We then see a new deadlock condition (on the pool_lock spinlock) [2],
which seemingly was avoided by taking the debug-bucket lock first.

We reproduce this by booting with debug_objects=1 and causing a lot of activity.

Daniel

--- [1]

[ INFO: possible irq lock inversion dependency detected ]
2.6.27-rc4-225c-debug #3
---------------------------------------------------------
rcu_sched_grace/9 just changed the state of lock:
(pool_lock){-...}, at: [<ffffffff80466c2c>] free_object+0x7c/0xc0
but this lock was taken by another, hard-irq-safe lock in the past:
(xtime_lock){++..}

and interrupts could create inverse lock ordering between them.

other info that might help us debug this:
no locks held by rcu_sched_grace/9.

the first lock's dependencies:
-> (pool_lock){-...} ops: 59 {
initial-use at:
[<ffffffff8026f795>]
__lock_acquire+0x1a5/0x1160
[<ffffffff802707e1>]
lock_acquire+0x91/0xc0
[<ffffffff806a2bb1>] _spin_lock+0x41/0x80
[<ffffffff804675fa>]
__debug_object_init+0x14a/0x3e0
[<ffffffff804678df>]
debug_object_init+0x1f/0x30
[<ffffffff80260eee>]
hrtimer_init+0x2e/0x50
[<ffffffff80237571>]
init_rt_bandwidth+0x41/0x60
[<ffffffff812f3810>]
sched_init+0x72/0x63d
[<ffffffff812e17e2>]
start_kernel+0x19c/0x456
[<ffffffff812e10a9>]
x86_64_start_reservations+0x99/0xb6
[<ffffffff812e11d0>]
x86_64_start_kernel+0xe2/0xe9
[<ffffffffffffffff>] 0xffffffffffffffff
hardirq-on-W at:
[<ffffffff8026fae9>]
__lock_acquire+0x4f9/0x1160
[<ffffffff802707e1>]
lock_acquire+0x91/0xc0
[<ffffffff806a2bb1>] _spin_lock+0x41/0x80
[<ffffffff80466c2c>]
free_object+0x7c/0xc0
[<ffffffff8046707e>]
debug_object_free+0xbe/0x130
[<ffffffff806a070e>]
schedule_timeout+0x7e/0xe0
[<ffffffff806a07ce>]
schedule_timeout_interruptible+0x1e/0x20
[<ffffffff8029cfb2>]
rcu_sched_grace_period+0xa2/0x3a0
[<ffffffff8025d50e>] kthread+0x4e/0x90
[<ffffffff8020d919>] child_rip+0xa/0x11
[<ffffffffffffffff>] 0xffffffffffffffff
}
... key at: [<ffffffff8088f5d8>] pool_lock+0x18/0x40

the second lock's dependencies:
-> (xtime_lock){++..} ops: 211 {
initial-use at:
[<ffffffff8026f795>]
__lock_acquire+0x1a5/0x1160
[<ffffffff802707e1>]
lock_acquire+0x91/0xc0
[<ffffffff806a2bb1>] _spin_lock+0x41/0x80
[<ffffffff812f5628>]
timekeeping_init+0x2f/0x144
[<ffffffff812e189d>]
start_kernel+0x257/0x456
[<ffffffff812e10a9>]
x86_64_start_reservations+0x99/0xb6
[<ffffffff812e11d0>]
x86_64_start_kernel+0xe2/0xe9
[<ffffffffffffffff>] 0xffffffffffffffff
in-hardirq-W at:
[<ffffffffffffffff>] 0xffffffffffffffff
in-softirq-W at:
[<ffffffffffffffff>] 0xffffffffffffffff
}
... key at: [<ffffffff80907220>] xtime_lock+0x20/0x40
-> (&obj_hash[i].lock){.+..} ops: 1003901 {
initial-use at:
[<ffffffff8026f795>]
__lock_acquire+0x1a5/0x1160
[<ffffffff802707e1>]
lock_acquire+0x91/0xc0
[<ffffffff806a2d43>]
_spin_lock_irqsave+0x53/0x90
[<ffffffff80467567>]
__debug_object_init+0xb7/0x3e0
[<ffffffff804678df>]
debug_object_init+0x1f/0x30
[<ffffffff80260eee>]
hrtimer_init+0x2e/0x50
[<ffffffff80237571>]
init_rt_bandwidth+0x41/0x60
[<ffffffff812f3810>]
sched_init+0x72/0x63d
[<ffffffff812e17e2>]
start_kernel+0x19c/0x456
[<ffffffff812e10a9>]
x86_64_start_reservations+0x99/0xb6
[<ffffffff812e11d0>]
x86_64_start_kernel+0xe2/0xe9
[<ffffffffffffffff>] 0xffffffffffffffff
in-softirq-W at:
[<ffffffffffffffff>] 0xffffffffffffffff
}
... key at: [<ffffffff81cd2eb0>] __key.16550+0x0/0x8
-> (pool_lock){-...} ops: 59 {
initial-use at:
[<ffffffff8026f795>]
__lock_acquire+0x1a5/0x1160
[<ffffffff802707e1>]
lock_acquire+0x91/0xc0
[<ffffffff806a2bb1>]
_spin_lock+0x41/0x80
[<ffffffff804675fa>]
__debug_object_init+0x14a/0x3e0
[<ffffffff804678df>]
debug_object_init+0x1f/0x30
[<ffffffff80260eee>]
hrtimer_init+0x2e/0x50
[<ffffffff80237571>]
init_rt_bandwidth+0x41/0x60
[<ffffffff812f3810>]
sched_init+0x72/0x63d
[<ffffffff812e17e2>]
start_kernel+0x19c/0x456
[<ffffffff812e10a9>]
x86_64_start_reservations+0x99/0xb6
[<ffffffff812e11d0>]
x86_64_start_kernel+0xe2/0xe9
[<ffffffffffffffff>]
0xffffffffffffffff
hardirq-on-W at:
[<ffffffff8026fae9>]
__lock_acquire+0x4f9/0x1160
[<ffffffff802707e1>]
lock_acquire+0x91/0xc0
[<ffffffff806a2bb1>]
_spin_lock+0x41/0x80
[<ffffffff80466c2c>]
free_object+0x7c/0xc0
[<ffffffff8046707e>]
debug_object_free+0xbe/0x130
[<ffffffff806a070e>]
schedule_timeout+0x7e/0xe0
[<ffffffff806a07ce>]
schedule_timeout_interruptible+0x1e/0x20
[<ffffffff8029cfb2>]
rcu_sched_grace_period+0xa2/0x3a0
[<ffffffff8025d50e>]
kthread+0x4e/0x90
[<ffffffff8020d919>]
child_rip+0xa/0x11
[<ffffffffffffffff>]
0xffffffffffffffff
}
... key at: [<ffffffff8088f5d8>] pool_lock+0x18/0x40
... acquired at:
[<ffffffff802703b1>] __lock_acquire+0xdc1/0x1160
[<ffffffff802707e1>] lock_acquire+0x91/0xc0
[<ffffffff806a2bb1>] _spin_lock+0x41/0x80
[<ffffffff804675fa>] __debug_object_init+0x14a/0x3e0
[<ffffffff804678df>] debug_object_init+0x1f/0x30
[<ffffffff80260eee>] hrtimer_init+0x2e/0x50
[<ffffffff80237571>] init_rt_bandwidth+0x41/0x60
[<ffffffff812f3810>] sched_init+0x72/0x63d
[<ffffffff812e17e2>] start_kernel+0x19c/0x456
[<ffffffff812e10a9>] x86_64_start_reservations+0x99/0xb6
[<ffffffff812e11d0>] x86_64_start_kernel+0xe2/0xe9
[<ffffffffffffffff>] 0xffffffffffffffff

... acquired at:
[<ffffffff802703b1>] __lock_acquire+0xdc1/0x1160
[<ffffffff802707e1>] lock_acquire+0x91/0xc0
[<ffffffff806a2d43>] _spin_lock_irqsave+0x53/0x90
[<ffffffff80467567>] __debug_object_init+0xb7/0x3e0
[<ffffffff804678df>] debug_object_init+0x1f/0x30
[<ffffffff80260eee>] hrtimer_init+0x2e/0x50
[<ffffffff812f577b>] ntp_init+0x1e/0x2b
[<ffffffff812f5633>] timekeeping_init+0x3a/0x144
[<ffffffff812e189d>] start_kernel+0x257/0x456
[<ffffffff812e10a9>] x86_64_start_reservations+0x99/0xb6
[<ffffffff812e11d0>] x86_64_start_kernel+0xe2/0xe9
[<ffffffffffffffff>] 0xffffffffffffffff

-> (clocksource_lock){++..} ops: 214 {
initial-use at:
[<ffffffff8026f795>]
__lock_acquire+0x1a5/0x1160
[<ffffffff802707e1>]
lock_acquire+0x91/0xc0
[<ffffffff806a2d43>]
_spin_lock_irqsave+0x53/0x90
[<ffffffff80266245>]
clocksource_get_next+0x15/0x60
[<ffffffff812f5638>]
timekeeping_init+0x3f/0x144
[<ffffffff812e189d>]
start_kernel+0x257/0x456
[<ffffffff812e10a9>]
x86_64_start_reservations+0x99/0xb6
[<ffffffff812e11d0>]
x86_64_start_kernel+0xe2/0xe9
[<ffffffffffffffff>] 0xffffffffffffffff
in-hardirq-W at:
[<ffffffffffffffff>] 0xffffffffffffffff
in-softirq-W at:
[<ffffffffffffffff>] 0xffffffffffffffff
}
... key at: [<ffffffff80877bb8>] clocksource_lock+0x18/0x40
... acquired at:
[<ffffffff802703b1>] __lock_acquire+0xdc1/0x1160
[<ffffffff802707e1>] lock_acquire+0x91/0xc0
[<ffffffff806a2d43>] _spin_lock_irqsave+0x53/0x90
[<ffffffff80266245>] clocksource_get_next+0x15/0x60
[<ffffffff812f5638>] timekeeping_init+0x3f/0x144
[<ffffffff812e189d>] start_kernel+0x257/0x456
[<ffffffff812e10a9>] x86_64_start_reservations+0x99/0xb6
[<ffffffff812e11d0>] x86_64_start_kernel+0xe2/0xe9
[<ffffffffffffffff>] 0xffffffffffffffff

-> (old_style_seqlock_init){++..} ops: 210 {
initial-use at:
[<ffffffffffffffff>] 0xffffffffffffffff
in-hardirq-W at:
[<ffffffffffffffff>] 0xffffffffffffffff
in-softirq-W at:
[<ffffffffffffffff>] 0xffffffffffffffff
}
... key at: [<ffffffff812d61a0>] nl80211_policy+0xda0/0x2c00
... acquired at:
[<ffffffffffffffff>] 0xffffffffffffffff

-> (ftrace_shutdown_lock){++..} ops: 480 {
initial-use at:
[<ffffffff8026f795>]
__lock_acquire+0x1a5/0x1160
[<ffffffff802707e1>]
lock_acquire+0x91/0xc0
[<ffffffff806a2d43>]
_spin_lock_irqsave+0x53/0x90
[<ffffffff802a4216>]
ftrace_record_ip+0x196/0x2f0
[<ffffffff8020c6b4>]
mcount_call+0x5/0x31
[<ffffffff812e1c9b>]
kernel_init+0x14d/0x1b2
[<ffffffff8020d919>] child_rip+0xa/0x11
[<ffffffffffffffff>] 0xffffffffffffffff
in-hardirq-W at:
[<ffffffffffffffff>] 0xffffffffffffffff
in-softirq-W at:
[<ffffffffffffffff>] 0xffffffffffffffff
}
... key at: [<ffffffff8087c1b8>] ftrace_shutdown_lock+0x18/0x40
... acquired at:
[<ffffffffffffffff>] 0xffffffffffffffff

stack backtrace:
Pid: 9, comm: rcu_sched_grace Not tainted 2.6.27-rc4-225c-debug #3

Call Trace:
[<ffffffff8026d8b2>] print_irq_inversion_bug+0x142/0x160
[<ffffffff8026dd27>] check_usage_backwards+0x67/0xb0
[<ffffffff8026ebd3>] mark_lock+0x363/0x7f0
[<ffffffff8026fae9>] __lock_acquire+0x4f9/0x1160
[<ffffffff802707e1>] lock_acquire+0x91/0xc0
[<ffffffff80466c2c>] ? free_object+0x7c/0xc0
[<ffffffff806a2bb1>] _spin_lock+0x41/0x80
[<ffffffff80466c2c>] ? free_object+0x7c/0xc0
[<ffffffff806a6bc9>] ? sub_preempt_count+0x69/0xd0
[<ffffffff80466c2c>] free_object+0x7c/0xc0
[<ffffffff8046707e>] debug_object_free+0xbe/0x130
[<ffffffff806a070e>] schedule_timeout+0x7e/0xe0
[<ffffffff802503a0>] ? process_timeout+0x0/0x10
[<ffffffff806a06f2>] ? schedule_timeout+0x62/0xe0
[<ffffffff8029cf10>] ? rcu_sched_grace_period+0x0/0x3a0
[<ffffffff806a07ce>] schedule_timeout_interruptible+0x1e/0x20
[<ffffffff8029cfb2>] rcu_sched_grace_period+0xa2/0x3a0
[<ffffffff8029cf10>] ? rcu_sched_grace_period+0x0/0x3a0
[<ffffffff8025d50e>] kthread+0x4e/0x90
[<ffffffff8020d919>] child_rip+0xa/0x11
[<ffffffff80239b8f>] ? finish_task_switch+0x5f/0x120
[<ffffffff806a356b>] ? _spin_unlock_irq+0x3b/0x70
[<ffffffff8020cf23>] ? restore_args+0x0/0x30
[<ffffffff8025d4c0>] ? kthread+0x0/0x90
[<ffffffff8020d90f>] ? child_rip+0x0/0x11

--- [2]

procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
r b swpd free buff cache si so bi bo in cs us sy id wa
58 0 63972 17316 16 145172 128 21176 128 21176 6054 8662 79 21 0 0
47 2 81020 14380 16 139472 1120 17052 1240 17052 6106 9532 77 23 0 0
52 1 86276 33656 16 137140 604 5304 796 5304 5349 7954 81 19 0 0
94 0 86276 32192 16 137484 480 0 772 0 5418 7618 84 16 0 0
88 0 86264 22416 16 137800 96 0 396 0 4746 5937 87 13 0 0
63 1 86200 54636 16 137932 1380 0 1408 0 5472 8007 82 18 0 0
47 0 86020 22848 16 138132 256 0 312 0 6126 12227 72 28 0 0
75 2 103828 20252 16 135500 528 17836 592 17836 6655 12862 69 31 0 0
21 0 128568 17536 16 128888 2336 24732 2336 24732 6762 12891 66 34 0 0
159 0 154996 16888 16 124808 480 26236 504 26236 5930 7689 80 20 0 0
45 0 165616 40108 16 120544 192 10696 248 10696 6136 9163 77 23 0 0
95 0 165616 27296 16 120632 924 0 940 0 5293 7468 82 18 0 0
BUG: NMI Watchdog detected LOCKUP on CPU0, ip ffffffff80214407, registers:
CPU 0
Modules linked in: rfcomm l2cap bluetooth kvm_intel kvm microcode
dvb_usb_dtt200u dvb_usb uvcvideo dvb_core compat_ioctl32 i2c_core
videodev v4l1_compat shpchp pcig
Pid: 6948, comm: spiral Not tainted 2.6.27-rc4-225c-debug #3
RIP: 0010:[<ffffffff80214407>] [<ffffffff80214407>] native_read_tsc+0x7/0x30
RSP: 0018:ffffffff8153ab70 EFLAGS: 00000002
RAX: 00000467c85cb001 RBX: ffffffff8088f5c0 RCX: 00000000c85cb001
RDX: 00000000c85cb001 RSI: 0000000000000103 RDI: 0000000000000001
RBP: ffffffff8153ab70 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: ffff8800cf978000 R12: 00000000c85cb001
R13: 0000000000000001 R14: 0000000000000000 R15: ffff88012a61c8c0
FS: 00007fb48cb796e0(0000) GS:ffffffff80e82dc0(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 00000000075212e6 CR3: 00000000cc1e6000 CR4: 00000000000026e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff4ff0 DR7: 0000000000000400
Process spiral (pid: 6948, threadinfo ffff8800cf950000, task ffff8800cf978000)
Stack: ffffffff8153aba0 ffffffff804560c7 ffffffff8088f5c0 0000000005b61b94
00000000d6915628 0000000000000001 ffffffff8153abb0 ffffffff80455fff
ffffffff8153abe0 ffffffff80466302 ffffffff8088f5d8 ffffffff8088f5c0
Call Trace:
<IRQ> [<ffffffff804560c7>] delay_tsc+0x67/0xd0
[<ffffffff80455fff>] __delay+0xf/0x20
[<ffffffff80466302>] _raw_spin_lock+0x122/0x170
[<ffffffff806a2bd1>] _spin_lock+0x61/0x80
[<ffffffff80466c2c>] ? free_object+0x7c/0xc0
[<ffffffff80466c2c>] free_object+0x7c/0xc0
[<ffffffff80466e0f>] __debug_check_no_obj_freed+0x19f/0x1e0
[<ffffffff80466e65>] debug_check_no_obj_freed+0x15/0x20
[<ffffffff802dff0c>] kmem_cache_free+0xec/0x110
[<ffffffff80517fa1>] ? scsi_pool_free_command+0x51/0x60
[<ffffffff80517fa1>] scsi_pool_free_command+0x51/0x60
[<ffffffff805184bf>] __scsi_put_command+0x5f/0xa0
[<ffffffff80518561>] scsi_put_command+0x61/0x70
[<ffffffff8051e47a>] scsi_next_command+0x3a/0x60
[<ffffffff8051e544>] scsi_end_request+0xa4/0xc0
[<ffffffff8051e68f>] scsi_io_completion+0x12f/0x440
[<ffffffff80517bf5>] scsi_finish_command+0x95/0xd0
[<ffffffff8051eb36>] scsi_softirq_done+0x86/0x110
[<ffffffff8043bbed>] blk_done_softirq+0x8d/0xa0
[<ffffffff8024ba04>] __do_softirq+0x74/0xf0
[<ffffffff8020dc7c>] call_softirq+0x1c/0x30
[<ffffffff8020f485>] do_softirq+0x75/0xb0
[<ffffffff8024b155>] irq_exit+0xa5/0xb0
[<ffffffff8020f7d3>] do_IRQ+0xe3/0x1d0
[<ffffffff80466c66>] ? free_object+0xb6/0xc0
[<ffffffff8020ce76>] ret_from_intr+0x0/0xf
<EOI> [<ffffffff80270ba0>] ? lock_release+0xe0/0x210
[<ffffffff806a3253>] ? _spin_unlock+0x23/0x60
[<ffffffff80466c66>] ? free_object+0xb6/0xc0
[<ffffffff8046707e>] ? debug_object_free+0xbe/0x130
[<ffffffff806a070e>] ? schedule_timeout+0x7e/0xe0
[<ffffffff802503a0>] ? process_timeout+0x0/0x10
[<ffffffff806a06f2>] ? schedule_timeout+0x62/0xe0
[<ffffffff802f8b3e>] ? do_select+0x4be/0x610
[<ffffffff802f8c90>] ? __pollwait+0x0/0x120
[<ffffffff8026f1d9>] ? trace_hardirqs_on_caller+0x29/0x1b0
[<ffffffff8026f1d9>] ? trace_hardirqs_on_caller+0x29/0x1b0
[<ffffffff8026f36d>] ? trace_hardirqs_on+0xd/0x10
[<ffffffff806a0b9e>] ? mutex_unlock+0xe/0x10
[<ffffffff8065919e>] ? unix_stream_recvmsg+0x32e/0x6d0
[<ffffffff8026f1d9>] ? trace_hardirqs_on_caller+0x29/0x1b0
[<ffffffff8026f36d>] ? trace_hardirqs_on+0xd/0x10
[<ffffffff802f8f4b>] ? core_sys_select+0x19b/0x2e0
[<ffffffff802e89e9>] ? do_sync_read+0xf9/0x140
[<ffffffff8025d8e0>] ? autoremove_wake_function+0x0/0x40
[<ffffffff806a6bc9>] ? sub_preempt_count+0x69/0xd0
[<ffffffff802f94b0>] ? sys_select+0xd0/0x1c0
[<ffffffff8020c86b>] ? system_call_fastpath+0x16/0x1b

Code: 90 90 90 90 55 89 f8 48 89 e5 e6 70 e4 71 c9 c3 0f 1f 40 00 55
89 f0 48 89 e5 e6 70 89 f8 e6 71 c9 c3 66 90 55 48 89 e5 0f 1f 00 <0f>
ae e8 0f 31 89 c1 0f 1f
BUG: NMI Watchdog detected LOCKUP<4>---[ end trace fd851c3db62e5044 ]---
Kernel panic - not syncing: Aiee, killing interrupt handler!
on CPU1, ip ffffffff80214407, registers:
CPU 1
Modules linked in: rfcomm l2cap bluetooth kvm_intel kvm microcode
dvb_usb_dtt200u dvb_usb uvcvideo dvb_core compat_ioctl32 i2c_core
videodev v4l1_compat shpchp pcig
Pid: 10150, comm: gcc Not tainted 2.6.27-rc4-225c-debug #3
RIP: 0010:[<ffffffff80214407>] [<ffffffff80214407>] native_read_tsc+0x7/0x30
RSP: 0018:ffff8800b6269c28 EFLAGS: 00000092
RAX: 0000000000000001 RBX: ffffffff8088f5c0 RCX: 00000000c85cafc2
RDX: 000000008b468b00 RSI: 0000000000000002 RDI: 0000000000000001
RBP: ffff8800b6269c28 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: ffff8800a65047e0 R12: 0000000005d22695
R13: 0000000000000001 R14: 0000000000000001 R15: ffff88009e9be940
FS: 00002b124e4fc6e0(0000) GS:ffff88012fa644b0(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 00002b8a265f5960 CR3: 00000000b61e9000 CR4: 00000000000026e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process gcc (pid: 10150, threadinfo ffff8800b6268000, task ffff8800a65047e0)
Stack: ffff8800b6269c58 ffffffff8045608a ffffffff8088f5c0 0000000005d22695
00000000d6915628 0000000000000001 ffff8800b6269c68 ffffffff80455fff
ffff8800b6269c98 ffffffff80466302 ffffffff8088f5d8 ffffffff8088f5c0
Call Trace:
[<ffffffff8045608a>] delay_tsc+0x2a/0xd0
[<ffffffff80455fff>] __delay+0xf/0x20
[<ffffffff80466302>] _raw_spin_lock+0x122/0x170
[<ffffffff806a2bd1>] _spin_lock+0x61/0x80
[<ffffffff80466c2c>] ? free_object+0x7c/0xc0
[<ffffffff80466c2c>] free_object+0x7c/0xc0
[<ffffffff80466e0f>] __debug_check_no_obj_freed+0x19f/0x1e0
[<ffffffff80466e65>] debug_check_no_obj_freed+0x15/0x20
[<ffffffff802dff0c>] kmem_cache_free+0xec/0x110
[<ffffffff8024264b>] ? __cleanup_signal+0x1b/0x20
[<ffffffff8024264b>] __cleanup_signal+0x1b/0x20
[<ffffffff80248273>] release_task+0x233/0x3d0
[<ffffffff80248960>] wait_consider_task+0x550/0x8b0
[<ffffffff80248e16>] do_wait+0x156/0x350
[<ffffffff8023b6f0>] ? default_wake_function+0x0/0x10
[<ffffffff802490a6>] sys_wait4+0x96/0xf0
[<ffffffff8020c86b>] system_call_fastpath+0x16/0x1b

Code: 90 90 90 90 55 89 f8 48 89 e5 e6 70 e4 71 c9 c3 0f 1f 40 00 55
89 f0 48 89 e5 e6 70 89 f8 e6 71 c9 c3 66 90 55 48 89 e5 0f 1f 00 <0f>
ae e8 0f 31 89 c1 0f 1f
---[ end trace fd851c3db62e5044 ]---
--
Daniel J Blueman