2022-06-20 09:18:01

by Greg Kroah-Hartman

[permalink] [raw]
Subject: Re: [PATCH v1] staging: r8188eu: an incorrect return value made the function always return fail

On Mon, Jun 20, 2022 at 04:54:13PM +0800, Kate Hsuan wrote:
> Since _SUCCESS (1) and _FAIL (0) are used to indicate the status of the
> functions. The previous commit 8ae7bf782eacad803f752c83a183393b0a67127b

In the future, please reference commit ids as the documentation asks, as
it's a much nicer way to understand things. Also this commit id is not
in Linus's tree or any tree that I can see, where did it come from?

> fixed and prevented dereferencing a NULL pointer through checking the
> return pointer. The NULL pointer check work properly but the return
> values (-ENOMEM on fail and 0 on success). This work fixed the return
> values to make sure the caller function will return the correct status.
>
> BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=2097526
> Signed-off-by: Kate Hsuan <[email protected]>
> ---
> drivers/staging/r8188eu/core/rtw_xmit.c | 8 +++-----
> 1 file changed, 3 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/staging/r8188eu/core/rtw_xmit.c b/drivers/staging/r8188eu/core/rtw_xmit.c
> index f4e9f6102539..2f8720db21d9 100644
> --- a/drivers/staging/r8188eu/core/rtw_xmit.c
> +++ b/drivers/staging/r8188eu/core/rtw_xmit.c
> @@ -180,10 +180,8 @@ s32 _rtw_init_xmit_priv(struct xmit_priv *pxmitpriv, struct adapter *padapter)
> pxmitpriv->free_xmit_extbuf_cnt = num_xmit_extbuf;
>
> res = rtw_alloc_hwxmits(padapter);
> - if (res) {
> - res = _FAIL;
> + if (res == _FAIL)
> goto exit;
> - }
>
> rtw_init_hwxmits(pxmitpriv->hwxmits, pxmitpriv->hwxmit_entry);
>
> @@ -1510,7 +1508,7 @@ int rtw_alloc_hwxmits(struct adapter *padapter)
>
> pxmitpriv->hwxmits = kzalloc(sizeof(struct hw_xmit) * pxmitpriv->hwxmit_entry, GFP_KERNEL);
> if (!pxmitpriv->hwxmits)
> - return -ENOMEM;
> + return _FAIL;

No, please let's fix up the callers to properly detect normal kernel
error values and get rid of all of the crazy _FAIL and _SUCCESS values
in this driver.

>
> hwxmits = pxmitpriv->hwxmits;
>
> @@ -1528,7 +1526,7 @@ int rtw_alloc_hwxmits(struct adapter *padapter)
> } else {
> }
>
> - return 0;
> + return _SUCCESS;

Same here, fix up the callers if they are checking this incorrectly.

thanks,

greg k-h


2022-06-20 10:03:17

by Kate Hsuan

[permalink] [raw]
Subject: Re: [PATCH v1] staging: r8188eu: an incorrect return value made the function always return fail

On Mon, Jun 20, 2022 at 5:01 PM Greg Kroah-Hartman
<[email protected]> wrote:
>
> On Mon, Jun 20, 2022 at 04:54:13PM +0800, Kate Hsuan wrote:
> > Since _SUCCESS (1) and _FAIL (0) are used to indicate the status of the
> > functions. The previous commit 8ae7bf782eacad803f752c83a183393b0a67127b
>
> In the future, please reference commit ids as the documentation asks, as
> it's a much nicer way to understand things. Also this commit id is not
> in Linus's tree or any tree that I can see, where did it come from?

Sorry about this. I'll improve this in my v2 patch.

>
> > fixed and prevented dereferencing a NULL pointer through checking the
> > return pointer. The NULL pointer check work properly but the return
> > values (-ENOMEM on fail and 0 on success). This work fixed the return
> > values to make sure the caller function will return the correct status.
> >
> > BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=2097526
> > Signed-off-by: Kate Hsuan <[email protected]>
> > ---
> > drivers/staging/r8188eu/core/rtw_xmit.c | 8 +++-----
> > 1 file changed, 3 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/staging/r8188eu/core/rtw_xmit.c b/drivers/staging/r8188eu/core/rtw_xmit.c
> > index f4e9f6102539..2f8720db21d9 100644
> > --- a/drivers/staging/r8188eu/core/rtw_xmit.c
> > +++ b/drivers/staging/r8188eu/core/rtw_xmit.c
> > @@ -180,10 +180,8 @@ s32 _rtw_init_xmit_priv(struct xmit_priv *pxmitpriv, struct adapter *padapter)
> > pxmitpriv->free_xmit_extbuf_cnt = num_xmit_extbuf;
> >
> > res = rtw_alloc_hwxmits(padapter);
> > - if (res) {
> > - res = _FAIL;
> > + if (res == _FAIL)
> > goto exit;
> > - }
> >
> > rtw_init_hwxmits(pxmitpriv->hwxmits, pxmitpriv->hwxmit_entry);
> >
> > @@ -1510,7 +1508,7 @@ int rtw_alloc_hwxmits(struct adapter *padapter)
> >
> > pxmitpriv->hwxmits = kzalloc(sizeof(struct hw_xmit) * pxmitpriv->hwxmit_entry, GFP_KERNEL);
> > if (!pxmitpriv->hwxmits)
> > - return -ENOMEM;
> > + return _FAIL;
>
> No, please let's fix up the callers to properly detect normal kernel
> error values and get rid of all of the crazy _FAIL and _SUCCESS values
> in this driver.

Okay.

>
> >
> > hwxmits = pxmitpriv->hwxmits;
> >
> > @@ -1528,7 +1526,7 @@ int rtw_alloc_hwxmits(struct adapter *padapter)
> > } else {
> > }
> >
> > - return 0;
> > + return _SUCCESS;
>
> Same here, fix up the callers if they are checking this incorrectly.
>
> thanks,
>
> greg k-h
>

Thank you :)

--
BR,
Kate