From: "F.A. SULAIMAN" <asha.16@itfac.mrt.ac.lk>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Greg KH <gregkh@linuxfoundation.org>,
devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] staging: rtl8723bs: fix memory leak error
Date: Thu, 2 Sep 2021 00:24:05 +0530 [thread overview]
Message-ID: <CAHnw0NAMaByr5m5Ai2APBc6Az_Lbb=TyCWmSdotVWKBJLPfVqg@mail.gmail.com> (raw)
In-Reply-To: <20210831084735.GL12231@kadam>
On Tue, Aug 31, 2021 at 2:18 PM Dan Carpenter <dan.carpenter@oracle.com> 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@itfac.mrt.ac.lk>
> > ---
> > 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.
next prev parent reply other threads:[~2021-09-01 18:54 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-30 19:33 [PATCH] staging: rtl8723bs: fix memory leak error F.A.Sulaiman
2021-08-31 8:47 ` Dan Carpenter
2021-09-01 18:54 ` F.A. SULAIMAN [this message]
2022-01-05 12:34 ` [PATCH v2] " F.A.Sulaiman
2022-01-05 14:37 ` Dan Carpenter
2022-01-06 21:00 ` kernel test robot
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAHnw0NAMaByr5m5Ai2APBc6Az_Lbb=TyCWmSdotVWKBJLPfVqg@mail.gmail.com' \
--to=asha.16@itfac.mrt.ac.lk \
--cc=dan.carpenter@oracle.com \
--cc=devel@driverdev.osuosl.org \
--cc=gregkh@linuxfoundation.org \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).