Re: Build regressions/improvements in v6.4 (wireless/airo)

[Randy Dunlap <rdunlap@infradead.org>]

Hi Geert,

[+ Adrian]

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.

I'm surprised that this is the only instance that gcc found/warned about.

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.

And the there is the general problem of not being able to build sh* cleanly any way.
(See all of the other build issues in
  http://kisskb.ellerman.id.au/kisskb/buildresult/14948832/
.)

Adrian, what toolchain do you use for arch/sh/ builds?


> 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?
Thanks.
---
From: Randy Dunlap <rdunlap@infradead.org>
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@infradead.org>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: lore.kernel.org/r/39abf2c7-24a-f167-91da-ed4c5435d1c4@linux-m68k.org
Cc: Kalle Valo <kvalo@kernel.org>
Cc: linux-wireless@vger.kernel.org
---
 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;
 
 	vwrq->value = le16_to_cpu(status_rid.currentXmitRate) * 500000;
 	/* If more than one rate, set auto */