[PATCH] qtnfmac: avoid uninitialized variable access

[PATCH] qtnfmac: avoid uninitialized variable access

[Arnd Bergmann]

When qtnf_trans_send_cmd_with_resp() fails, we have not yet initialized
'resp', as pointed out by a valid gcc warning:

drivers/net/wireless/quantenna/qtnfmac/commands.c: In function 'qtnf_cmd_send_with_reply':
drivers/net/wireless/quantenna/qtnfmac/commands.c:133:54: error: 'resp' may be used uninitialized in this function [-Werror=maybe-uninitialized]

Since 'resp_skb' is also not set here, we can skip all further
processing and just print the warning and return the failure code.

Fixes: c6ed298ffe09 ("qtnfmac: cleanup and unify command error handling")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/net/wireless/quantenna/qtnfmac/commands.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/quantenna/qtnfmac/commands.c b/drivers/net/wireless/quantenna/qtnfmac/commands.c
index bfdc1ad30c13..9b211459684a 100644
--- a/drivers/net/wireless/quantenna/qtnfmac/commands.c
+++ b/drivers/net/wireless/quantenna/qtnfmac/commands.c
@@ -111,7 +111,7 @@ static int qtnf_cmd_send_with_reply(struct qtnf_bus *bus,
 
 	ret = qtnf_trans_send_cmd_with_resp(bus, cmd_skb, &resp_skb);
 	if (ret)
-		goto out;
+		goto out_noresp;
 
 	resp = (const struct qlink_resp *)resp_skb->data;
 	ret = qtnf_cmd_check_reply_header(resp, cmd_id, mac_id, vif_id,
@@ -132,6 +132,7 @@ static int qtnf_cmd_send_with_reply(struct qtnf_bus *bus,
 	if (!ret && resp)
 		return qtnf_cmd_resp_result_decode(le16_to_cpu(resp->result));
 
+out_noresp:
 	pr_warn("VIF%u.%u: cmd 0x%.4X failed: %d\n",
 		mac_id, vif_id, le16_to_cpu(cmd->cmd_id), ret);
 
-- 
2.18.0

Re: [PATCH] qtnfmac: avoid uninitialized variable access

[Sergey Matyukevich]

Hello Arnd,

> When qtnf_trans_send_cmd_with_resp() fails, we have not yet initialized
> 'resp', as pointed out by a valid gcc warning:
> 
> drivers/net/wireless/quantenna/qtnfmac/commands.c: In function 'qtnf_cmd_send_with_reply':
> drivers/net/wireless/quantenna/qtnfmac/commands.c:133:54: error: 'resp' may be used uninitialized in this function [-Werror=maybe-uninitialized]
> 
> Since 'resp_skb' is also not set here, we can skip all further
> processing and just print the warning and return the failure code.
> 
> Fixes: c6ed298ffe09 ("qtnfmac: cleanup and unify command error handling")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Thanks for the patch! And for reminding me that I forgot to enable
gcc warnings in CI builds in addition to sparse checks.

Reviewed-by: Sergey Matyukevich <sergey.matyukevich.os@quantenna.com>

Regards,
Sergey

Re: [PATCH] qtnfmac: avoid uninitialized variable access

[Sergey Matyukevich]

> > When qtnf_trans_send_cmd_with_resp() fails, we have not yet initialized
> > 'resp', as pointed out by a valid gcc warning:
> >
> > drivers/net/wireless/quantenna/qtnfmac/commands.c: In function 'qtnf_cmd_send_with_reply':
> > drivers/net/wireless/quantenna/qtnfmac/commands.c:133:54: error: 'resp' may be used uninitialized in this function [-Werror=maybe-uninitialized]
> >
> > Since 'resp_skb' is also not set here, we can skip all further
> > processing and just print the warning and return the failure code.
> >
> > Fixes: c6ed298ffe09 ("qtnfmac: cleanup and unify command error handling")
> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> 
> Thanks for the patch! And for reminding me that I forgot to enable
> gcc warnings in CI builds in addition to sparse checks.
> 
> Reviewed-by: Sergey Matyukevich <sergey.matyukevich.os@quantenna.com>

Hi Kalle,

Could you please hold back applying this patch for now. We have got
another report for the same function, this time static analysis tool
warning. It looks like the patch from Arnd does not cover both cases.
So we will take a closer look and send a combined fix later.

Regards,
Sergey

Re: [PATCH] qtnfmac: avoid uninitialized variable access

[Kalle Valo]

Sergey Matyukevich <sergey.matyukevich.os@quantenna.com> writes:

>> > When qtnf_trans_send_cmd_with_resp() fails, we have not yet initialized
>> > 'resp', as pointed out by a valid gcc warning:
>> >
>> > drivers/net/wireless/quantenna/qtnfmac/commands.c: In function
>> > 'qtnf_cmd_send_with_reply':
>> > drivers/net/wireless/quantenna/qtnfmac/commands.c:133:54: error:
>> > 'resp' may be used uninitialized in this function
>> > [-Werror=maybe-uninitialized]
>> >
>> > Since 'resp_skb' is also not set here, we can skip all further
>> > processing and just print the warning and return the failure code.
>> >
>> > Fixes: c6ed298ffe09 ("qtnfmac: cleanup and unify command error handling")
>> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>> 
>> Thanks for the patch! And for reminding me that I forgot to enable
>> gcc warnings in CI builds in addition to sparse checks.
>> 
>> Reviewed-by: Sergey Matyukevich <sergey.matyukevich.os@quantenna.com>
>
> Hi Kalle,
>
> Could you please hold back applying this patch for now. We have got
> another report for the same function, this time static analysis tool
> warning. It looks like the patch from Arnd does not cover both cases.
> So we will take a closer look and send a combined fix later.

Ok, I'll drop this from my queue. Please resend whatever patch I need to
apply.

-- 
Kalle Valo