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From: javi.merino@arm.com (Javi Merino)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: pl330: Fix a race condition
Date: Wed, 05 Oct 2011 13:57:09 +0100	[thread overview]
Message-ID: <4E8C5425.80303@arm.com> (raw)
In-Reply-To: <4E7896D8.5090606@arm.com>

On 20/09/11 14:36, Javi Merino wrote:
> On 19/09/11 19:07, Jassi Brar wrote:
>> IIUIC your race scenario should be taken care of simply by doing...
>>
>> diff --git a/arch/arm/common/pl330.c b/arch/arm/common/pl330.c
>> index 97912fa..7129cfb 100644
>> --- a/arch/arm/common/pl330.c
>> +++ b/arch/arm/common/pl330.c
>> @@ -1546,7 +1546,7 @@ int pl330_chan_ctrl(void *ch_id, enum pl330_chan_op op)
>>
>>  		/* Start the next */
>>  	case PL330_OP_START:
>> -		if (!_start(thrd))
>> +		if (!_thrd_active(thrd) && !_start(thrd))
>>  			ret = -EIO;
>>  		break;
>>
> 
> My first reaction was this was just moving the race condition, but
> thinking about it carefully, it looks like a better (simpler) solution.
> 
>> Could you please test if it fixes the issue?
> 
> Yes, I'll kick off runs later today and see how it goes.  I don't have a
> way to reproduce the bug consistently, I just do lots of DMA
> transactions and eventually, I end up hitting it.  I'll run it overnight
> and see if it fixes it or not.

I have run a lot of tests using your patch and I haven't been able to
reproduce the bug so your proposed solution is probably a better
(simpler) fix than mine.

Cheers,
Javi

  reply	other threads:[~2011-10-05 12:57 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-19 17:11 [PATCH] ARM: pl330: Fix a race condition Javi Merino
2011-09-19 18:07 ` Jassi Brar
2011-09-20 13:36   ` Javi Merino
2011-10-05 12:57     ` Javi Merino [this message]
2011-10-06  9:10       ` [PATCH v2] " Javi Merino
2011-11-05 19:05         ` Thomas Abraham
2011-11-07 10:48           ` Javi Merino
2011-11-07 11:03             ` Thomas Abraham
2011-11-28  8:23             ` Boojin Kim
2011-11-28 16:36               ` Javi Merino
2011-11-29  3:41                 ` Boojin Kim
2011-11-29  9:53                   ` Javi Merino
2011-11-29 10:37                     ` Jassi Brar
2011-12-07  7:52                       ` Kukjin Kim
2011-12-07 10:01                         ` Javi Merino
2011-12-07 20:54                           ` Javi Merino
2011-12-09 11:58                             ` Javi Merino
2011-12-09 13:04                               ` Jassi Brar
2011-12-09 13:41                                 ` Javi Merino
2011-12-09 14:15                                   ` Jassi Brar
2011-12-09 14:52                                     ` Javi Merino
2011-12-09 16:50                                       ` Jassi Brar
2011-12-09 19:50                                         ` Javi Merino
2011-12-11 10:51                                           ` Jassi Brar
2011-12-11 15:09                                             ` Javi Merino
2011-12-11 17:10                                               ` Jassi Brar
2011-12-11 17:42                                                 ` Javi Merino
2011-12-11 19:27                                                   ` [PATCH] ARM: PL330: Fix driver freeze Javi Merino
2011-12-15 17:48                                                     ` Javi Merino
2011-12-16  9:01                                                       ` Tushar Behera
2011-12-16  6:27                                                     ` Jassi Brar

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