Re: [PATCH v1 1/1] fpga: m10bmc-sec: Fix possible memory leak of flash_buf

[Xu Yilun]

On 2022-09-16 at 17:20:43 -0700, Tom Rix wrote:
> 
> On 9/16/22 4:52 PM, Russ Weight wrote:
> > There is an error check following the allocation of flash_buf that returns
> > without freeing flash_buf. It makes more sense to do the error check
> > before the allocation and the reordering eliminates the memory leak.
> > 
> > Reported-by: kernel test robot <lkp@xxxxxxxxx>
> > Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> > Fixes: 154afa5c31cd ("fpga: m10bmc-sec: expose max10 flash update count")
> > Signed-off-by: Russ Weight <russell.h.weight@xxxxxxxxx>
> Reviewed-by: Tom Rix <trix@xxxxxxxxxx>

Acked-by: Xu Yilun <yilun.xu@xxxxxxxxx>

Applied to for-6.0

> > Cc: <stable@xxxxxxxxxxxxxxx>
> > ---
> >   drivers/fpga/intel-m10-bmc-sec-update.c | 8 ++++----
> >   1 file changed, 4 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/fpga/intel-m10-bmc-sec-update.c b/drivers/fpga/intel-m10-bmc-sec-update.c
> > index 526c8cdd1474..79d48852825e 100644
> > --- a/drivers/fpga/intel-m10-bmc-sec-update.c
> > +++ b/drivers/fpga/intel-m10-bmc-sec-update.c
> > @@ -148,10 +148,6 @@ static ssize_t flash_count_show(struct device *dev,
> >   	stride = regmap_get_reg_stride(sec->m10bmc->regmap);
> >   	num_bits = FLASH_COUNT_SIZE * 8;
> > -	flash_buf = kmalloc(FLASH_COUNT_SIZE, GFP_KERNEL);
> > -	if (!flash_buf)
> > -		return -ENOMEM;
> > -
> >   	if (FLASH_COUNT_SIZE % stride) {
> >   		dev_err(sec->dev,
> >   			"FLASH_COUNT_SIZE (0x%x) not aligned to stride (0x%x)\n",
> > @@ -160,6 +156,10 @@ static ssize_t flash_count_show(struct device *dev,
> >   		return -EINVAL;
> >   	}
> > +	flash_buf = kmalloc(FLASH_COUNT_SIZE, GFP_KERNEL);
> > +	if (!flash_buf)
> > +		return -ENOMEM;
> > +
> >   	ret = regmap_bulk_read(sec->m10bmc->regmap, STAGING_FLASH_COUNT,
> >   			       flash_buf, FLASH_COUNT_SIZE / stride);
> >   	if (ret) {
>