Re: [blk] WARNING: CPU: 0 PID: 300 at kernel/softirq.c:156 _local_bh_enable_ip()
Hi,
I think one fix is to use "_local_bh_enable()" instead of "local_bh_enable()"
in u64_stats_fetch_retry_bh(). There's no enabling of irq in
_local_bh_enable().
But I wonder why we do "WARN_ON_ONCE(!irqs_disabled()
)" in
_local_bh_enable()? What's the bad thing if someone call
_local_bh_enable() with irqs_diabled()?
Is below change acceptable?
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 490fcbb..f446763 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -142,9 +142,11 @@ EXPORT_SYMBOL(_local_bh_enable);
void __local_bh_enable_ip(unsigned long ip, unsigned int cnt)
{
+ unsigned long flags;
+
WARN_ON_ONCE(in_irq() || irqs_disabled());
#ifdef CONFIG_TRACE_IRQFLAGS
- local_irq_disable();
+ raw_local_irq_save(flags);
#endif
/*
* Are softirqs going to be turned on now:
@@ -167,7 +169,7 @@ void __local_bh_enable_ip(unsigned long ip,
unsigned int cnt)
preempt_count_dec();
#ifdef CONFIG_TRACE_IRQFLAGS
- local_irq_enable();
+ raw_local_irq_restore(flags);
#endif
preempt_check_resched();
}
Zhiguo
On Tue, Apr 22, 2014 at 9:06 AM, Jens Axboe wrote:
> On 2014-04-20 14:30, Jet Chen wrote:
>>
>> Hi Zhiguo,
>>
>> I got the below dmesg and the first bad commit is
>>
>> git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
>> commit 2c575026fae6e63771bd2a4c1d407214a8096a89
>> Author: Hong Zhiguo
>> AuthorDate: Wed Nov 20 10:35:05 2013 -0700
>> Commit: Jens Axboe
>> CommitDate: Wed Nov 20 15:33:04 2013 -0700
>>
>> Update of blkg_stat and blkg_rwstat may happen in bh context.
>> While u64_stats_fetch_retry is only preempt_disable on 32bit
>> UP system. This is not enough to avoid preemption by bh and
>> may read strange 64 bit value.
>> Signed-off-by: Hong Zhiguo
>> Acked-by: Tejun Heo
>> Cc: sta...@kernel.org
>> Signed-off-by: Jens Axboe
>>
>>
>>
>>
>> +---+++
>> | | 82023bb7f7 |
>> 2c575026fa |
>>
>> +---+++
>> | boot_successes| 47 |
>> 0 |
>> | boot_failures | 13 |
>> 20 |
>> | BUG:kernel_boot_hang | 13 |
>> 5 |
>> | inconsistent_IN-SOFTIRQ-W-SOFTIRQ-ON-W_usage | 0 |
>> 15 |
>> | backtrace:smpboot_thread_fn | 0 |
>> 15 |
>> | backtrace:vfs_read| 0 |
>> 9 |
>> | backtrace:SyS_read| 0 |
>> 9 |
>> | WARNING:CPU:PID:at_kernel/softirq.c:_local_bh_enable_ip() | 0 |
>> 7 |
>> | BUG:spinlock_lockup_suspected_on_CPU | 0 |
>> 1 |
>> | backtrace:do_mount| 0 |
>> 6 |
>> | backtrace:SyS_mount | 0 |
>> 6 |
>> | backtrace:async_run_entry_fn | 0 |
>> 0 |
>>
>> +---+++
>>
>> [ 12.318816] WARNING: CPU: 0 PID: 300 at kernel/softirq.c:156
>> _local_bh_enable_ip+0x34/0x97()
>
>
> Does this still happen with 3.15-rc2?
>
> --
> Jens Axboe
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majord...@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
--
best regards
Hong Zhiguo
--
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Please read the FAQ at http://www.tux.org/lkml/
Re: [blk] WARNING: CPU: 0 PID: 300 at kernel/softirq.c:156 _local_bh_enable_ip()
Hi,
I think one fix is to use _local_bh_enable() instead of local_bh_enable()
in u64_stats_fetch_retry_bh(). There's no enabling of irq in
_local_bh_enable().
But I wonder why we do WARN_ON_ONCE(!irqs_disabled()
) in
_local_bh_enable()? What's the bad thing if someone call
_local_bh_enable() with irqs_diabled()?
Is below change acceptable?
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 490fcbb..f446763 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -142,9 +142,11 @@ EXPORT_SYMBOL(_local_bh_enable);
void __local_bh_enable_ip(unsigned long ip, unsigned int cnt)
{
+ unsigned long flags;
+
WARN_ON_ONCE(in_irq() || irqs_disabled());
#ifdef CONFIG_TRACE_IRQFLAGS
- local_irq_disable();
+ raw_local_irq_save(flags);
#endif
/*
* Are softirqs going to be turned on now:
@@ -167,7 +169,7 @@ void __local_bh_enable_ip(unsigned long ip,
unsigned int cnt)
preempt_count_dec();
#ifdef CONFIG_TRACE_IRQFLAGS
- local_irq_enable();
+ raw_local_irq_restore(flags);
#endif
preempt_check_resched();
}
Zhiguo
On Tue, Apr 22, 2014 at 9:06 AM, Jens Axboe ax...@kernel.dk wrote:
On 2014-04-20 14:30, Jet Chen wrote:
Hi Zhiguo,
I got the below dmesg and the first bad commit is
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
commit 2c575026fae6e63771bd2a4c1d407214a8096a89
Author: Hong Zhiguo zhiguoh...@tencent.com
AuthorDate: Wed Nov 20 10:35:05 2013 -0700
Commit: Jens Axboe ax...@kernel.dk
CommitDate: Wed Nov 20 15:33:04 2013 -0700
Update of blkg_stat and blkg_rwstat may happen in bh context.
While u64_stats_fetch_retry is only preempt_disable on 32bit
UP system. This is not enough to avoid preemption by bh and
may read strange 64 bit value.
Signed-off-by: Hong Zhiguo zhiguoh...@tencent.com
Acked-by: Tejun Heo t...@kernel.org
Cc: sta...@kernel.org
Signed-off-by: Jens Axboe ax...@kernel.dk
+---+++
| | 82023bb7f7 |
2c575026fa |
+---+++
| boot_successes| 47 |
0 |
| boot_failures | 13 |
20 |
| BUG:kernel_boot_hang | 13 |
5 |
| inconsistent_IN-SOFTIRQ-W-SOFTIRQ-ON-W_usage | 0 |
15 |
| backtrace:smpboot_thread_fn | 0 |
15 |
| backtrace:vfs_read| 0 |
9 |
| backtrace:SyS_read| 0 |
9 |
| WARNING:CPU:PID:at_kernel/softirq.c:_local_bh_enable_ip() | 0 |
7 |
| BUG:spinlock_lockup_suspected_on_CPU | 0 |
1 |
| backtrace:do_mount| 0 |
6 |
| backtrace:SyS_mount | 0 |
6 |
| backtrace:async_run_entry_fn | 0 |
0 |
+---+++
[ 12.318816] WARNING: CPU: 0 PID: 300 at kernel/softirq.c:156
_local_bh_enable_ip+0x34/0x97()
Does this still happen with 3.15-rc2?
--
Jens Axboe
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
--
best regards
Hong Zhiguo
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [blk] WARNING: CPU: 0 PID: 300 at kernel/softirq.c:156 _local_bh_enable_ip()
On 2014-04-20 14:30, Jet Chen wrote: Hi Zhiguo, I got the below dmesg and the first bad commit is git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master commit 2c575026fae6e63771bd2a4c1d407214a8096a89 Author: Hong Zhiguo AuthorDate: Wed Nov 20 10:35:05 2013 -0700 Commit: Jens Axboe CommitDate: Wed Nov 20 15:33:04 2013 -0700 Update of blkg_stat and blkg_rwstat may happen in bh context. While u64_stats_fetch_retry is only preempt_disable on 32bit UP system. This is not enough to avoid preemption by bh and may read strange 64 bit value. Signed-off-by: Hong Zhiguo Acked-by: Tejun Heo Cc: sta...@kernel.org Signed-off-by: Jens Axboe +---+++ | | 82023bb7f7 | 2c575026fa | +---+++ | boot_successes| 47 | 0 | | boot_failures | 13 | 20 | | BUG:kernel_boot_hang | 13 | 5 | | inconsistent_IN-SOFTIRQ-W-SOFTIRQ-ON-W_usage | 0 | 15 | | backtrace:smpboot_thread_fn | 0 | 15 | | backtrace:vfs_read| 0 | 9 | | backtrace:SyS_read| 0 | 9 | | WARNING:CPU:PID:at_kernel/softirq.c:_local_bh_enable_ip() | 0 | 7 | | BUG:spinlock_lockup_suspected_on_CPU | 0 | 1 | | backtrace:do_mount| 0 | 6 | | backtrace:SyS_mount | 0 | 6 | | backtrace:async_run_entry_fn | 0 | 0 | +---+++ [ 12.318816] WARNING: CPU: 0 PID: 300 at kernel/softirq.c:156 _local_bh_enable_ip+0x34/0x97() Does this still happen with 3.15-rc2? -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [blk] WARNING: CPU: 0 PID: 300 at kernel/softirq.c:156 _local_bh_enable_ip()
On 2014-04-20 14:30, Jet Chen wrote: Hi Zhiguo, I got the below dmesg and the first bad commit is git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master commit 2c575026fae6e63771bd2a4c1d407214a8096a89 Author: Hong Zhiguo zhiguoh...@tencent.com AuthorDate: Wed Nov 20 10:35:05 2013 -0700 Commit: Jens Axboe ax...@kernel.dk CommitDate: Wed Nov 20 15:33:04 2013 -0700 Update of blkg_stat and blkg_rwstat may happen in bh context. While u64_stats_fetch_retry is only preempt_disable on 32bit UP system. This is not enough to avoid preemption by bh and may read strange 64 bit value. Signed-off-by: Hong Zhiguo zhiguoh...@tencent.com Acked-by: Tejun Heo t...@kernel.org Cc: sta...@kernel.org Signed-off-by: Jens Axboe ax...@kernel.dk +---+++ | | 82023bb7f7 | 2c575026fa | +---+++ | boot_successes| 47 | 0 | | boot_failures | 13 | 20 | | BUG:kernel_boot_hang | 13 | 5 | | inconsistent_IN-SOFTIRQ-W-SOFTIRQ-ON-W_usage | 0 | 15 | | backtrace:smpboot_thread_fn | 0 | 15 | | backtrace:vfs_read| 0 | 9 | | backtrace:SyS_read| 0 | 9 | | WARNING:CPU:PID:at_kernel/softirq.c:_local_bh_enable_ip() | 0 | 7 | | BUG:spinlock_lockup_suspected_on_CPU | 0 | 1 | | backtrace:do_mount| 0 | 6 | | backtrace:SyS_mount | 0 | 6 | | backtrace:async_run_entry_fn | 0 | 0 | +---+++ [ 12.318816] WARNING: CPU: 0 PID: 300 at kernel/softirq.c:156 _local_bh_enable_ip+0x34/0x97() Does this still happen with 3.15-rc2? -- Jens Axboe -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
