Hi Vihas,
On 4/24/22 19:31, Vihas Makwana wrote:
> There's a NULL check on pmlmepriv in rtw_mlme.c:112 which makes no sense
> as rtw_free_mlme_priv_ie_data() dereferences it unconditionally and it
> would have already crashed at this point.
> Fix this by moving rtw_free_mlme_priv_ie_data() inside the check.
>
> Signed-off-by: Vihas Makwana <[email protected]>
That's good catch, but looks like the check is just redundant
This function is called only from it's wrapper called
rtw_free_mlme_priv() and rtw_free_mlme_priv() is called from 2 places:
4 drivers/staging/r8188eu/os_dep/os_intfs.c|531 col 2|
rtw_free_mlme_priv(&padapter->mlmepriv);
5 drivers/staging/r8188eu/os_dep/os_intfs.c|579 col 2|
rtw_free_mlme_priv(&padapter->mlmepriv);
_Very_ unlikely that `&padapter->mlmepriv` expression will become NULL.
> ---
> drivers/staging/r8188eu/core/rtw_mlme.c | 8 +++-----
> 1 file changed, 3 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/staging/r8188eu/core/rtw_mlme.c b/drivers/staging/r8188eu/core/rtw_mlme.c
> index 081c02417..87c754462 100644
> --- a/drivers/staging/r8188eu/core/rtw_mlme.c
> +++ b/drivers/staging/r8188eu/core/rtw_mlme.c
> @@ -109,12 +109,10 @@ void rtw_free_mlme_priv_ie_data(struct mlme_priv *pmlmepriv)
>
> void _rtw_free_mlme_priv(struct mlme_priv *pmlmepriv)
> {
> -
> - rtw_free_mlme_priv_ie_data(pmlmepriv);
> -
> - if (pmlmepriv)
> + if (pmlmepriv) {
> + rtw_free_mlme_priv_ie_data(pmlmepriv);
> vfree(pmlmepriv->free_bss_buf);
> -
> + }
> }
>
> struct wlan_network *_rtw_alloc_network(struct mlme_priv *pmlmepriv)/* _queue *free_queue) */
With regards,
Pavel Skripkin
On Mon, Apr 25, 2022 at 12:30 AM Pavel Skripkin <[email protected]> wrote:
>
> Hi Vihas,
>
> On 4/24/22 19:31, Vihas Makwana wrote:
> > There's a NULL check on pmlmepriv in rtw_mlme.c:112 which makes no sense
> > as rtw_free_mlme_priv_ie_data() dereferences it unconditionally and it
> > would have already crashed at this point.
> > Fix this by moving rtw_free_mlme_priv_ie_data() inside the check.
> >
> > Signed-off-by: Vihas Makwana <[email protected]>
>
> That's good catch, but looks like the check is just redundant
>
> This function is called only from it's wrapper called
> rtw_free_mlme_priv() and rtw_free_mlme_priv() is called from 2 places:
>
> 4 drivers/staging/r8188eu/os_dep/os_intfs.c|531 col 2|
> rtw_free_mlme_priv(&padapter->mlmepriv);
> 5 drivers/staging/r8188eu/os_dep/os_intfs.c|579 col 2|
> rtw_free_mlme_priv(&padapter->mlmepriv);
>
> _Very_ unlikely that `&padapter->mlmepriv` expression will become NULL.
>
So I guess either we should remove the check or mark it with the
`unlikely()` macro.
>
> > ---
> > drivers/staging/r8188eu/core/rtw_mlme.c | 8 +++-----
> > 1 file changed, 3 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/staging/r8188eu/core/rtw_mlme.c b/drivers/staging/r8188eu/core/rtw_mlme.c
> > index 081c02417..87c754462 100644
> > --- a/drivers/staging/r8188eu/core/rtw_mlme.c
> > +++ b/drivers/staging/r8188eu/core/rtw_mlme.c
> > @@ -109,12 +109,10 @@ void rtw_free_mlme_priv_ie_data(struct mlme_priv *pmlmepriv)
> >
> > void _rtw_free_mlme_priv(struct mlme_priv *pmlmepriv)
> > {
> > -
> > - rtw_free_mlme_priv_ie_data(pmlmepriv);
> > -
> > - if (pmlmepriv)
> > + if (pmlmepriv) {
> > + rtw_free_mlme_priv_ie_data(pmlmepriv);
> > vfree(pmlmepriv->free_bss_buf);
> > -
> > + }
> > }
> >
> > struct wlan_network *_rtw_alloc_network(struct mlme_priv *pmlmepriv)/* _queue *free_queue) */
>
>
>
>
> With regards,
> Pavel Skripkin
--
Thanks,
Vihas
On Mon, Apr 25, 2022 at 11:25:32PM +0530, Vihas Makwana wrote:
> On Mon, Apr 25, 2022 at 12:30 AM Pavel Skripkin <[email protected]> wrote:
> >
> > Hi Vihas,
> >
> > On 4/24/22 19:31, Vihas Makwana wrote:
> > > There's a NULL check on pmlmepriv in rtw_mlme.c:112 which makes no sense
> > > as rtw_free_mlme_priv_ie_data() dereferences it unconditionally and it
> > > would have already crashed at this point.
> > > Fix this by moving rtw_free_mlme_priv_ie_data() inside the check.
> > >
> > > Signed-off-by: Vihas Makwana <[email protected]>
> >
> > That's good catch, but looks like the check is just redundant
> >
> > This function is called only from it's wrapper called
> > rtw_free_mlme_priv() and rtw_free_mlme_priv() is called from 2 places:
> >
> > 4 drivers/staging/r8188eu/os_dep/os_intfs.c|531 col 2|
> > rtw_free_mlme_priv(&padapter->mlmepriv);
> > 5 drivers/staging/r8188eu/os_dep/os_intfs.c|579 col 2|
> > rtw_free_mlme_priv(&padapter->mlmepriv);
> >
> > _Very_ unlikely that `&padapter->mlmepriv` expression will become NULL.
> >
> So I guess either we should remove the check or mark it with the
> `unlikely()` macro.
The likely/unlikely() macros are only for when you can prove it makes a
difference to benchmark. They hurt readability, but they're important
for optimizing the fast path.
Just remove the check.
regards,
dan carpenter