1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
|
From: Thomas Gleixner <tglx@linutronix.de>
Date: Mon, 1 Jul 2013 11:02:42 +0200
Subject: [PATCH 192/342] workqueue: Prevent workqueue versus ata-piix livelock
Origin: https://git.kernel.org/cgit/linux/kernel/git/rt/linux-stable-rt.git/commit?id=7e44200efbc637bb4e2d7632e624fae8d13d050f
An Intel i7 system regularly detected rcu_preempt stalls after the kernel
was upgraded from 3.6-rt to 3.8-rt. When the stall happened, disk I/O was no
longer possible, unless the system was restarted.
The kernel message was:
INFO: rcu_preempt self-detected stall on CPU { 6}
[..]
NMI backtrace for cpu 6
CPU 6
Pid: 119, comm: irq/19-ata_piix Not tainted 3.8.13-rt13 #11 Shuttle Inc. SX58/SX58
RIP: 0010:[<ffffffff8124ca60>] [<ffffffff8124ca60>] ip_compute_csum+0x30/0x30
RSP: 0018:ffff880333303cb0 EFLAGS: 00000002
RAX: 0000000000000006 RBX: 00000000000003e9 RCX: 0000000000000034
RDX: 0000000000000000 RSI: ffffffff81aa16d0 RDI: 0000000000000001
RBP: ffff880333303ce8 R08: ffffffff81aa16d0 R09: ffffffff81c1b8cc
R10: 0000000000000000 R11: 0000000000000000 R12: 000000000005161f
R13: 0000000000000006 R14: ffffffff81aa16d0 R15: 0000000000000002
FS: 0000000000000000(0000) GS:ffff880333300000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000003c1b2bb420 CR3: 0000000001a0f000 CR4: 00000000000007e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process irq/19-ata_piix (pid: 119, threadinfo ffff88032d88a000, task ffff88032df80000)
Stack:
ffffffff8124cb32 000000000005161e 00000000000003e9 0000000000001000
0000000000009022 ffffffff81aa16d0 0000000000000002 ffff880333303cf8
ffffffff8124caa9 ffff880333303d08 ffffffff8124cad2 ffff880333303d28
Call Trace:
<IRQ>
[<ffffffff8124cb32>] ? delay_tsc+0x33/0xe3
[<ffffffff8124caa9>] __delay+0xf/0x11
[<ffffffff8124cad2>] __const_udelay+0x27/0x29
[<ffffffff8102d1fa>] native_safe_apic_wait_icr_idle+0x39/0x45
[<ffffffff8102dc9b>] __default_send_IPI_dest_field.constprop.0+0x1e/0x58
[<ffffffff8102dd1e>] default_send_IPI_mask_sequence_phys+0x49/0x7d
[<ffffffff81030326>] physflat_send_IPI_all+0x17/0x19
[<ffffffff8102de53>] arch_trigger_all_cpu_backtrace+0x50/0x79
[<ffffffff810b21d0>] rcu_check_callbacks+0x1cb/0x568
[<ffffffff81048c9c>] ? raise_softirq+0x2e/0x35
[<ffffffff81086be0>] ? tick_sched_do_timer+0x38/0x38
[<ffffffff8104f653>] update_process_times+0x44/0x55
[<ffffffff81086866>] tick_sched_handle+0x4a/0x59
[<ffffffff81086c1c>] tick_sched_timer+0x3c/0x5b
[<ffffffff81062845>] __run_hrtimer+0x9b/0x158
[<ffffffff810631d8>] hrtimer_interrupt+0x172/0x2aa
[<ffffffff8102d498>] smp_apic_timer_interrupt+0x76/0x89
[<ffffffff814d881d>] apic_timer_interrupt+0x6d/0x80
<EOI>
[<ffffffff81057cd2>] ? __local_lock_irqsave+0x17/0x4a
[<ffffffff81059336>] try_to_grab_pending+0x42/0x17e
[<ffffffff8105a699>] mod_delayed_work_on+0x32/0x88
[<ffffffff8105a70b>] mod_delayed_work+0x1c/0x1e
[<ffffffff8122ae84>] blk_run_queue_async+0x37/0x39
[<ffffffff81230985>] flush_end_io+0xf1/0x107
[<ffffffff8122e0da>] blk_finish_request+0x21e/0x264
[<ffffffff8122e162>] blk_end_bidi_request+0x42/0x60
[<ffffffff8122e1ba>] blk_end_request+0x10/0x12
[<ffffffff8132de46>] scsi_io_completion+0x1bf/0x492
[<ffffffff81335cec>] ? sd_done+0x298/0x2ef
[<ffffffff81325a02>] scsi_finish_command+0xe9/0xf2
[<ffffffff8132dbcb>] scsi_softirq_done+0x106/0x10f
[<ffffffff812333d3>] blk_done_softirq+0x77/0x87
[<ffffffff8104826f>] do_current_softirqs+0x172/0x2e1
[<ffffffff810aa820>] ? irq_thread_fn+0x3a/0x3a
[<ffffffff81048466>] local_bh_enable+0x43/0x72
[<ffffffff810aa866>] irq_forced_thread_fn+0x46/0x52
[<ffffffff810ab089>] irq_thread+0x8c/0x17c
[<ffffffff810ab179>] ? irq_thread+0x17c/0x17c
[<ffffffff810aaffd>] ? wake_threads_waitq+0x44/0x44
[<ffffffff8105eb18>] kthread+0x8d/0x95
[<ffffffff8105ea8b>] ? __kthread_parkme+0x65/0x65
[<ffffffff814d7b7c>] ret_from_fork+0x7c/0xb0
[<ffffffff8105ea8b>] ? __kthread_parkme+0x65/0x65
The state of softirqd of this CPU at the time of the crash was:
ksoftirqd/6 R running task 0 53 2 0x00000000
ffff88032fc39d18 0000000000000046 ffff88033330c4c0 ffff8803303f4710
ffff88032fc39fd8 ffff88032fc39fd8 0000000000000000 0000000000062500
ffff88032df88000 ffff8803303f4710 0000000000000000 ffff88032fc38000
Call Trace:
[<ffffffff8105a3ae>] ? __queue_work+0x27c/0x27c
[<ffffffff814d178c>] preempt_schedule+0x61/0x76
[<ffffffff8106cccf>] migrate_enable+0xe5/0x1df
[<ffffffff8105a3ae>] ? __queue_work+0x27c/0x27c
[<ffffffff8104ef52>] run_timer_softirq+0x161/0x1d6
[<ffffffff8104826f>] do_current_softirqs+0x172/0x2e1
[<ffffffff8104840b>] run_ksoftirqd+0x2d/0x45
[<ffffffff8106658a>] smpboot_thread_fn+0x2ea/0x308
[<ffffffff810662a0>] ? test_ti_thread_flag+0xc/0xc
[<ffffffff810662a0>] ? test_ti_thread_flag+0xc/0xc
[<ffffffff8105eb18>] kthread+0x8d/0x95
[<ffffffff8105ea8b>] ? __kthread_parkme+0x65/0x65
[<ffffffff814d7afc>] ret_from_fork+0x7c/0xb0
[<ffffffff8105ea8b>] ? __kthread_parkme+0x65/0x65
Apparently, the softirq demon and the ata_piix IRQ handler were waiting
for each other to finish ending up in a livelock. After the below patch
was applied, the system no longer crashes.
Reported-by: Carsten Emde <C.Emde@osadl.org>
Proposed-by: Thomas Gleixner <tglx@linutronix.de>
Tested by: Carsten Emde <C.Emde@osadl.org>
Signed-off-by: Carsten Emde <C.Emde@osadl.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
kernel/workqueue.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 2b4c052c51b3..6e73e3eaca5e 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -51,6 +51,7 @@
#include <linux/nmi.h>
#include <linux/kvm_para.h>
#include <linux/locallock.h>
+#include <linux/delay.h>
#include "workqueue_internal.h"
@@ -1282,7 +1283,7 @@ static int try_to_grab_pending(struct work_struct *work, bool is_dwork,
local_unlock_irqrestore(pendingb_lock, *flags);
if (work_is_canceling(work))
return -ENOENT;
- cpu_relax();
+ cpu_chill();
return -EAGAIN;
}
|
