Re: [PATCH] idxd: avoid deadlock in process_misc_interrupts()

From: Jerry Snitselaar <jsnitsel@redhat.com>
To: "Yu, Fenghua" <fenghua.yu@intel.com>
Cc: linux-kernel@vger.kernel.org, "Jiang,
	Dave" <dave.jiang@intel.com>, Vinod Koul <vkoul@kernel.org>,
	dmaengine@vger.kernel.org
Subject: Re: [PATCH] idxd: avoid deadlock in process_misc_interrupts()
Date: Mon, 12 Dec 2022 13:08:23 -0700	[thread overview]
Message-ID: <446A5C1E-E50B-4270-9781-5D945109541E@redhat.com> (raw)
In-Reply-To: <IA1PR11MB6097183F44E96BE3FAF119DA9BE29@IA1PR11MB6097.namprd11.prod.outlook.com>

> On Dec 12, 2022, at 11:47 AM, Yu, Fenghua <fenghua.yu@intel.com> wrote:
> 
> Hi, Jerry,
> 
>> idxd_device_clear_state() now grabs the idxd->dev_lock itself, so don't grab the
>> lock prior to calling it.
>> 
>> This was seen in testing after dmar fault occurred on system, resulting in lockup
>> stack traces.
>> 
> 
> Please add Fixes: cf4ac3fef338 ...
> 
>> Cc: Fenghua Yu <fenghua.yu@intel.com>
>> Cc: Dave Jiang <dave.jiang@intel.com>
>> Cc: Vinod Koul <vkoul@kernel.org>
>> Cc: dmaengine@vger.kernel.org
>> Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>
>> ---
>> drivers/dma/idxd/irq.c | 2 --
>> 1 file changed, 2 deletions(-)
>> 
>> diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c index
>> 743ead5ebc57..5b9921475be6 100644
>> --- a/drivers/dma/idxd/irq.c
>> +++ b/drivers/dma/idxd/irq.c
>> @@ -324,13 +324,11 @@ static int process_misc_interrupts(struct idxd_device
>> *idxd, u32 cause)
>>            idxd->state = IDXD_DEV_HALTED;
>>            idxd_wqs_quiesce(idxd);
>>            idxd_wqs_unmap_portal(idxd);
>> -            spin_lock(&idxd->dev_lock);
>>            idxd_device_clear_state(idxd);
>>            dev_err(&idxd->pdev->dev,
>>                "idxd halted, need %s.\n",
>>                gensts.reset_type == IDXD_DEVICE_RESET_FLR ?
>>                "FLR" : "system reset");
>> -            spin_unlock(&idxd->dev_lock);
>>            return -ENXIO;
>>        }
>>    }
>> --
>> 2.37.2
> 
> Thanks.
> 
> -Fenghua
> 

Hi Fenghua,

I think this was merged back in August. Not at my system to get the exact date.

Regards,
Jerry