Hi Randy,
On Sun, Jul 9, 2023 at 4:46 AM Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote:
> On 6/26/23 01:24, Geert Uytterhoeven wrote:
> > On Mon, 26 Jun 2023, Geert Uytterhoeven wrote:
> >> JFYI, when comparing v6.4[1] to v6.4-rc7[3], the summaries are:
> >> - build errors: +1/-0
> >
> > + /kisskb/src/drivers/net/wireless/cisco/airo.c: error: 'status_rid.currentXmitRate' is used uninitialized [-Werror=uninitialized]: => 6163:45
>
> I cannot reproduce this build error. (I don't doubt the problem, just having a problem
> making it happen for me.)
> I have tried it with gcc-11.1.0, gcc-11.3.0, and gcc-13.1.0.
Which is similar to kisskb, using sh4-linux-gcc (GCC) 11.3.0...
> I'm surprised that this is the only instance that gcc found/warned about.
Indeed.
>
> I have a patch for this one instance, but there are 40+ instances of
> readStatusRid()
> readConfigRid()
> readSsidRid()
> readStatsRid()
> readCapabilityRid()
> that don't check the return status of the function calls.
>
> I suppose that a patch can quieten the compiler error/warning, but given
> the 40+ other problems, it won't make the driver any noticeably better IMO.
Indeed...
> > sh4-gcc11/sh-allmodconfig
> > seen before
> >
> > This is actually a real issue, and it's been here since basically forever.
> >
> > drivers/net/wireless/cisco/airo.c:
> >
> > static int airo_get_rate(struct net_device *dev,
> > struct iw_request_info *info,
> > union iwreq_data *wrqu,
> > char *extra)
> > {
> > struct iw_param *vwrq = &wrqu->bitrate;
> > struct airo_info *local = dev->ml_priv;
> > StatusRid status_rid; /* Card status info */
> >
> > readStatusRid(local, &status_rid, 1);
> >
> > ==> vwrq->value = le16_to_cpu(status_rid.currentXmitRate) * 500000;
> > ...
> > }
> >
> > static int readStatusRid(struct airo_info *ai, StatusRid *statr, int lock)
> > {
> > return PC4500_readrid(ai, RID_STATUS, statr, sizeof(*statr), lock);
> > }
> >
> > static int PC4500_readrid(struct airo_info *ai, u16 rid, void *pBuf, int len, int lock)
> > {
> > u16 status;
> > int rc = SUCCESS;
> >
> > if (lock) {
> > if (down_interruptible(&ai->sem))
> > return ERROR;
> >
> > pBuf output buffer contents not initialized.
> >
> > }
> > ...
> > }
> >
> >
> >> [1] http://kisskb.ellerman.id.au/kisskb/branch/linus/head/6995e2de6891c724bfeb2db33d7b87775f913ad1/ (all 160 configs)
> >> [3] http://kisskb.ellerman.id.au/kisskb/branch/linus/head/45a3e24f65e90a047bef86f927ebdc4c710edaa1/ (all 160 configs)
>
> I appreciate the synopsis. Here's a patch. WDYT?
> ---
> From: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
> Subject: [PATCH] wifi: airo: avoid uninitialized warning in airo_get_rate()
>
> Quieten a gcc (11.3.0) build error or warning by checking the function
> call status and returning -EIO if the function call failed.
> This is similar to what several other wireless drivers do for the
> SIOCGIWRATE ioctl call.
>
> drivers/net/wireless/cisco/airo.c: error: 'status_rid.currentXmitRate' is used uninitialized [-Werror=uninitialized]
>
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
> Reported-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
> Link: lore.kernel.org/r/39abf2c7-24a-f167-91da-ed4c5435d1c4@xxxxxxxxxxxxxx
> Cc: Kalle Valo <kvalo@xxxxxxxxxx>
> Cc: linux-wireless@xxxxxxxxxxxxxxx
> ---
> drivers/net/wireless/cisco/airo.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff -- a/drivers/net/wireless/cisco/airo.c b/drivers/net/wireless/cisco/airo.c
> --- a/drivers/net/wireless/cisco/airo.c
> +++ b/drivers/net/wireless/cisco/airo.c
> @@ -6157,8 +6157,11 @@ static int airo_get_rate(struct net_devi
> struct iw_param *vwrq = &wrqu->bitrate;
> struct airo_info *local = dev->ml_priv;
> StatusRid status_rid; /* Card status info */
> + int ret;
>
> - readStatusRid(local, &status_rid, 1);
> + ret = readStatusRid(local, &status_rid, 1);
> + if (ret)
> + return -EIO;
That's about the best we can do without further surgery.
E.g. PC4500_readrid() should return a proper error code instead of
just ERROR/SUCCESS.
The case gcc complains about is when lock = 1 and the call to
down_interruptible() fails, for which -EBUSY would be appropriate.
>
> vwrq->value = le16_to_cpu(status_rid.currentXmitRate) * 500000;
> /* If more than one rate, set auto */
>
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
