On 05/09/2011 04:32 PM, Julia Lawall wrote:
> On Mon, 9 May 2011, Vladimir Motyka wrote:
>
>> When allocation of idata fails there was a null dereferece.
>
> Why not have a different label for the two cases? That would make the
> code easier to statically analyze, and perhaps be more understandable as
> well.
>
> julia
>
I think You are right. So it could be better like this?
diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 3dec493..a03cdc6 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -237,7 +237,7 @@ static struct mmc_blk_ioc_data
*mmc_blk_ioctl_copy_from_user(
idata = kzalloc(sizeof(*idata), GFP_KERNEL);
if (!idata) {
err = -ENOMEM;
- goto copy_err;
+ goto alloc_err;
}
if (copy_from_user(&idata->ic, user, sizeof(idata->ic))) {
@@ -266,9 +266,9 @@ static struct mmc_blk_ioc_data
*mmc_blk_ioctl_copy_from_user(
return idata;
copy_err:
- if(idata)
- kfree(idata->buf);
+ kfree(idata->buf);
kfree(idata);
+alloc_err:
return ERR_PTR(err);
}
Or it could return right after allocation fails so there needn't be
goto. It is simplier, but maybe worse looking and to read. What is your
opinion?
Vladimir Motyka
>
>> Signed-off-by: Vladimir Motyka <vladimir.motyka@xxxxxxxxx>
>>
>> ---
>> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
>> index 407836d..3dec493 100644
>> --- a/drivers/mmc/card/block.c
>> +++ b/drivers/mmc/card/block.c
>> @@ -266,10 +266,10 @@ static struct mmc_blk_ioc_data
>> *mmc_blk_ioctl_copy_from_user(
>> return idata;
>>
>> copy_err:
>> - kfree(idata->buf);
>> + if(idata)
>> + kfree(idata->buf);
>> kfree(idata);
>> return ERR_PTR(err);
>> -
>> }
>>
>> static int mmc_blk_ioctl_cmd(struct block_device *bdev,
>> --
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