On Tue, Aug 31, 2021 at 2:18 PM Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote:
>
> On Tue, Aug 31, 2021 at 01:03:55AM +0530, F.A.Sulaiman wrote:
> > Smatch reported memory leak bug in rtl8723b_FirmwareDownload function.
> > The problem is pFirmware memory is not released in release_fw1.
> > Instead of redirecting to release_fw1 we can turn it into exit
> > and free the memory.
> >
> > Signed-off-by: F.A. SULAIMAN <asha.16@xxxxxxxxxxxxxxx>
> > ---
> > drivers/staging/rtl8723bs/hal/rtl8723b_hal_init.c | 3 +--
> > 1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/drivers/staging/rtl8723bs/hal/rtl8723b_hal_init.c b/drivers/staging/rtl8723bs/hal/rtl8723b_hal_init.c
> > index de8caa6cd418..b59c2aa3a9d8 100644
> > --- a/drivers/staging/rtl8723bs/hal/rtl8723b_hal_init.c
> > +++ b/drivers/staging/rtl8723bs/hal/rtl8723b_hal_init.c
> > @@ -436,7 +436,7 @@ s32 rtl8723b_FirmwareDownload(struct adapter *padapter, bool bUsedWoWLANFw)
> > if (pFirmware->fw_length > FW_8723B_SIZE) {
> > rtStatus = _FAIL;
> > DBG_871X_LEVEL(_drv_emerg_, "Firmware size:%u exceed %u\n", pFirmware->fw_length, FW_8723B_SIZE);
> > - goto release_fw1;
> > + goto exit;
> > }
>
> The current tree doesn't have DBG_871X_LEVEL() so you must be working
> against something old. You need to work against linux-next or staging
> next.
>
> Your patch fixes a bug, but it would be better to just re-write the
> error handling for this function. There is another bug that a bunch
> of error paths don't call release_firmware(fw). Use the "Free the Last
> Thing" method.
>
> pFirmware = kzalloc(sizeof(struct rt_firmware), GFP_KERNEL);
> if (!pFirmware)
> return _FAIL;
>
> The last thing we allocated is "pFirmware" so free that if we have an
> error.
>
> pBTFirmware = kzalloc(sizeof(struct rt_firmware), GFP_KERNEL);
> if (!pBTFirmware) {
> rtStatus = _FAIL;
> goto free_firmware;
> }
>
> Now the last thing is pBTFirmware.
>
> rtStatus = request_firmware(&fw, fwfilepath, device);
> if (rtStatus) {
> rtStatus = _FAIL;
> goto free_bt_firmware;
> }
>
> Now the last thing is "fw". But this is a bit tricky because we're
> going to release it as soon as possible and not wait until the end of
> the function. There isn't a reason for this... We can change that or
> keep it as-is. If we keep it as is, then the we'll just call
> release_firmware(fw); before the goto free_bt_firmware; The current
> code leaks fw on a bunch of error paths.
>
> pFirmware->fw_buffer_sz = kmemdup(fw->data, fw->size, GFP_KERNEL);
> if (!pFirmware->fw_buffer_sz) {
> rtStatus = _FAIL;
> release_firmware(fw);
> goto free_bt_firmware;
> }
>
> Or:
>
> pFirmware->fw_buffer_sz = kmemdup(fw->data, fw->size, GFP_KERNEL);
> if (!pFirmware->fw_buffer_sz) {
> rtStatus = _FAIL;
> goto release_fw;
> }
>
> Now the last thing is pFirmware->fw_buffer_sz. Etc.
>
> Then at the end it's just:
>
> free_fw_buffer:
> kfree(pFirmware->fw_buffer_sz);
> release_fw:
> release_firmware(fw);
> free_bt_firmware:
> kfree(pBTFirmware);
> free_firmware:
> kfree(pFirmware);
>
> return rtStatus;
> }
>
Thank you! I'll do the changes and send you a v2 patch.
Best Regards,
Asha Sulaiman.
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