From: Fenghua Yu <fenghua.yu@intel.com>
To: Dave Jiang <dave.jiang@intel.com>, Vinod Koul <vkoul@kernel.org>
Cc: <dmaengine@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Lijun Pan <lijun.pan@intel.com>
Subject: Re: [PATCH] dmaengine: idxd: Avoid unnecessary destruction of file_ida
Date: Mon, 29 Apr 2024 13:56:53 -0700 [thread overview]
Message-ID: <8d384dcf-8688-ce7d-1dcf-432aad706221@intel.com> (raw)
In-Reply-To: <b4d845d8-24e3-43ce-b1d4-e121f799e26c@intel.com>
Hi, Vinod,
On 1/30/24 07:34, Dave Jiang wrote:
>
>
> On 1/29/24 18:39, Fenghua Yu wrote:
>> file_ida is allocated during cdev open and is freed accordingly
>> during cdev release. This sequence is guaranteed by driver file
>> operations. Therefore, there is no need to destroy an already empty
>> file_ida when the WQ cdev is removed.
>>
>> Worse, ida_free() in cdev release may happen after destruction of
>> file_ida per WQ cdev. This can lead to accessing an id in file_ida
>> after it has been destroyed, resulting in a kernel panic.
>>
>> Remove ida_destroy(&file_ida) to address these issues.
>>
>> Fixes: e6fd6d7e5f0f ("dmaengine: idxd: add a device to represent the file opened")
>> Signed-off-by: Lijun Pan <lijun.pan@intel.com>
>> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
>
> Reviewed-by: Dave Jiang <dave.jiang@intel.com>
>> ---
>> drivers/dma/idxd/cdev.c | 1 -
>> 1 file changed, 1 deletion(-)
>>
>> diff --git a/drivers/dma/idxd/cdev.c b/drivers/dma/idxd/cdev.c
>> index baa51927675c..3311c920f47a 100644
>> --- a/drivers/dma/idxd/cdev.c
>> +++ b/drivers/dma/idxd/cdev.c
>> @@ -1272,7 +1272,6 @@ void idxd_wq_del_cdev(struct idxd_wq *wq)
>> struct idxd_cdev *idxd_cdev;
>>
>> idxd_cdev = wq->idxd_cdev;
>> - ida_destroy(&file_ida);
>> wq->idxd_cdev = NULL;
>> cdev_device_del(&idxd_cdev->cdev, cdev_dev(idxd_cdev));
>> put_device(cdev_dev(idxd_cdev));
I noticed this patch was not merged to upstream yet. The patch is still
cleanly applied to upstream.
Could you please help merge this patch?
Thanks.
-Fenghua
next prev parent reply other threads:[~2024-04-29 20:56 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-30 1:39 [PATCH] dmaengine: idxd: Avoid unnecessary destruction of file_ida Fenghua Yu
2024-01-30 15:34 ` Dave Jiang
2024-04-29 20:56 ` Fenghua Yu [this message]
2024-05-04 12:47 ` Vinod Koul
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