[PATCH 1/3] media: tuners: tda18271: fix error code handling in tda18271_attach()

[PATCH 1/3] media: tuners: tda18271: fix error code handling in tda18271_attach()

[Roman Smirnov]

tda18271_attach() uses the hybrid_tuner_request_state() macro.
It may return the error code -ENOMEM, but the function handle
the value 0 instead.

Found by Linux Verification Center (linuxtesting.org) with Svace.

Fixes: b9302fa7ed97 ("media: tuners: fix error return code of hybrid_tuner_request_state()")
Signed-off-by: Roman Smirnov <r.smirnov@omp.ru>
---
 drivers/media/tuners/tda18271-fe.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/tuners/tda18271-fe.c b/drivers/media/tuners/tda18271-fe.c
index a7e721baaa99..23432210f06a 100644
--- a/drivers/media/tuners/tda18271-fe.c
+++ b/drivers/media/tuners/tda18271-fe.c
@@ -1255,7 +1255,7 @@ struct dvb_frontend *tda18271_attach(struct dvb_frontend *fe, u8 addr,
 					      hybrid_tuner_instance_list,
 					      i2c, addr, "tda18271");
 	switch (instance) {
-	case 0:
+	case -ENOMEM:
 		goto fail;
 	case 1:
 		/* new tuner instance */
-- 
2.34.1

[PATCH 2/3] media: tuners: xc5000: fix error code handling in xc5000_attach()

[Roman Smirnov]

xc5000_attach() uses the hybrid_tuner_request_state() macro.
It may return the error code -ENOMEM, but the function handle
the value 0 instead.

Found by Linux Verification Center (linuxtesting.org) with Svace.

Fixes: b9302fa7ed97 ("media: tuners: fix error return code of hybrid_tuner_request_state()")
Signed-off-by: Roman Smirnov <r.smirnov@omp.ru>
---
 drivers/media/tuners/xc5000.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/tuners/xc5000.c b/drivers/media/tuners/xc5000.c
index 2182e5b7b606..6e47edee8ac3 100644
--- a/drivers/media/tuners/xc5000.c
+++ b/drivers/media/tuners/xc5000.c
@@ -1379,7 +1379,7 @@ struct dvb_frontend *xc5000_attach(struct dvb_frontend *fe,
 					      hybrid_tuner_instance_list,
 					      i2c, cfg->i2c_address, "xc5000");
 	switch (instance) {
-	case 0:
+	case -ENOMEM:
 		goto fail;
 	case 1:
 		/* new tuner instance */
-- 
2.34.1

[PATCH 3/3] media: tuners: tuner_simple: fix error code handling in simple_tuner_attach()

[Roman Smirnov]

simple_tuner_attach() uses the hybrid_tuner_request_state() macro.
It may return the error code -ENOMEM, but the function handle
the value 0 instead.

Found by Linux Verification Center (linuxtesting.org) with Svace.

Fixes: b9302fa7ed97 ("media: tuners: fix error return code of hybrid_tuner_request_state()")
Signed-off-by: Roman Smirnov <r.smirnov@omp.ru>
---
 drivers/media/tuners/tuner-simple.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/tuners/tuner-simple.c b/drivers/media/tuners/tuner-simple.c
index 8fb186b25d6a..713ce2455910 100644
--- a/drivers/media/tuners/tuner-simple.c
+++ b/drivers/media/tuners/tuner-simple.c
@@ -1089,7 +1089,7 @@ struct dvb_frontend *simple_tuner_attach(struct dvb_frontend *fe,
 					      i2c_adap, i2c_addr,
 					      "tuner-simple");
 	switch (instance) {
-	case 0:
+	case -ENOMEM:
 		mutex_unlock(&tuner_simple_list_mutex);
 		return NULL;
 	case 1:
-- 
2.34.1

Re: [PATCH 3/3] media: tuners: tuner_simple: fix error code handling in simple_tuner_attach()

[Sergey Shtylyov]

Hello!

   Should have been "tuner-simple:" in the subject... :-)

On 4/16/24 2:45 PM, Roman Smirnov wrote:

> simple_tuner_attach() uses the hybrid_tuner_request_state() macro.
> It may return the error code -ENOMEM, but the function handle
> the value 0 instead.
> 
> Found by Linux Verification Center (linuxtesting.org) with Svace.
> 
> Fixes: b9302fa7ed97 ("media: tuners: fix error return code of hybrid_tuner_request_state()")
> Signed-off-by: Roman Smirnov <r.smirnov@omp.ru>

Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>

[...]

MBR, Sergey

Re: [PATCH 1/3] media: tuners: tda18271: fix error code handling in tda18271_attach()

[Sergey Shtylyov]

On 4/16/24 2:45 PM, Roman Smirnov wrote:

> tda18271_attach() uses the hybrid_tuner_request_state() macro.
> It may return the error code -ENOMEM, but the function handle
> the value 0 instead.
> 
> Found by Linux Verification Center (linuxtesting.org) with Svace.
> 
> Fixes: b9302fa7ed97 ("media: tuners: fix error return code of hybrid_tuner_request_state()")
> Signed-off-by: Roman Smirnov <r.smirnov@omp.ru>

Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>

[...]

MBR, Sergey

Re: [PATCH 2/3] media: tuners: xc5000: fix error code handling in xc5000_attach()

[Sergey Shtylyov]

On 4/16/24 2:45 PM, Roman Smirnov wrote:

> xc5000_attach() uses the hybrid_tuner_request_state() macro.
> It may return the error code -ENOMEM, but the function handle

   Handles (just noticed that grammar issue in all 3 patches).

> the value 0 instead.
> 
> Found by Linux Verification Center (linuxtesting.org) with Svace.
> 
> Fixes: b9302fa7ed97 ("media: tuners: fix error return code of hybrid_tuner_request_state()")
> Signed-off-by: Roman Smirnov <r.smirnov@omp.ru>

Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>

[...]

MBR, Sergey

Re: [lvc-project] [PATCH 1/3] media: tuners: tda18271: fix error code handling in tda18271_attach()

[Fedor Pchelkin]

Hello Roman,

On Tue, 16. Apr 14:45, Roman Smirnov wrote:
> tda18271_attach() uses the hybrid_tuner_request_state() macro.
> It may return the error code -ENOMEM, but the function handle
> the value 0 instead.

Maybe hybrid_tuner_request_state macro declaration should be fixed to
generate zero in case of a memory allocation failure?

At least it has a comment stating the following
 * 0 - no instances, indicates an error - kzalloc must have failed

And supposedly a number of drivers implemented the error handling based on
this assumption.

The drivers mentioned in this series are not the only ones susceptible to
the problem. Grepping through "hybrid_tuner_request_state" calls also gives
out tda9887, xc2028, r820t and others.

> 
> Found by Linux Verification Center (linuxtesting.org) with Svace.
> 
> Fixes: b9302fa7ed97 ("media: tuners: fix error return code of hybrid_tuner_request_state()")
> Signed-off-by: Roman Smirnov <r.smirnov@omp.ru>
> ---
>  drivers/media/tuners/tda18271-fe.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/media/tuners/tda18271-fe.c b/drivers/media/tuners/tda18271-fe.c
> index a7e721baaa99..23432210f06a 100644
> --- a/drivers/media/tuners/tda18271-fe.c
> +++ b/drivers/media/tuners/tda18271-fe.c
> @@ -1255,7 +1255,7 @@ struct dvb_frontend *tda18271_attach(struct dvb_frontend *fe, u8 addr,
>  					      hybrid_tuner_instance_list,
>  					      i2c, addr, "tda18271");
>  	switch (instance) {
> -	case 0:
> +	case -ENOMEM:
>  		goto fail;
>  	case 1:
>  		/* new tuner instance */
> -- 
> 2.34.1
> 

Re: [lvc-project] [PATCH 1/3] media: tuners: tda18271: fix error code handling in tda18271_attach()

[Fedor Pchelkin]

On Wed, 24. Apr 21:06, Fedor Pchelkin wrote:
> Hello Roman,
> 
> On Tue, 16. Apr 14:45, Roman Smirnov wrote:
> > tda18271_attach() uses the hybrid_tuner_request_state() macro.
> > It may return the error code -ENOMEM, but the function handle
> > the value 0 instead.
> 
> Maybe hybrid_tuner_request_state macro declaration should be fixed to
> generate zero in case of a memory allocation failure?
> 
> At least it has a comment stating the following
>  * 0 - no instances, indicates an error - kzalloc must have failed
> 
> And supposedly a number of drivers implemented the error handling based on
> this assumption.
> 
> The drivers mentioned in this series are not the only ones susceptible to
> the problem. Grepping through "hybrid_tuner_request_state" calls also gives
> out tda9887, xc2028, r820t and others.
> 
> > 
> > Found by Linux Verification Center (linuxtesting.org) with Svace.
> > 
> > Fixes: b9302fa7ed97 ("media: tuners: fix error return code of hybrid_tuner_request_state()")

Looking more thoroughly, I think commit b9302fa7ed97 ("media: tuners: fix
error return code of hybrid_tuner_request_state()") should be reverted
because it just contradicts with the return values contract which is stated
in the comment for the macro and which is followed by all the existing
drivers.

__ret should be assigned 0 in error case as was before the commit.

> > Signed-off-by: Roman Smirnov <r.smirnov@omp.ru>
> > ---
> >  drivers/media/tuners/tda18271-fe.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/media/tuners/tda18271-fe.c b/drivers/media/tuners/tda18271-fe.c
> > index a7e721baaa99..23432210f06a 100644
> > --- a/drivers/media/tuners/tda18271-fe.c
> > +++ b/drivers/media/tuners/tda18271-fe.c
> > @@ -1255,7 +1255,7 @@ struct dvb_frontend *tda18271_attach(struct dvb_frontend *fe, u8 addr,
> >  					      hybrid_tuner_instance_list,
> >  					      i2c, addr, "tda18271");
> >  	switch (instance) {
> > -	case 0:
> > +	case -ENOMEM:
> >  		goto fail;
> >  	case 1:
> >  		/* new tuner instance */
> > -- 
> > 2.34.1
> >