[PATCH] request_irq() always returns -EINVAL with a NULL handler.

[PATCH] request_irq() always returns -EINVAL with a NULL handler.

[Rusty Russell]

I assume that these ancient network drivers were trying to find out if
an irq is available.  eepro.c expecting +EBUSY was doubly wrong.

I'm not sure that can_request_irq() is the right thing, but these drivers
are definitely wrong.

request_irq should BUG() on bad input, and these would have been found
earlier.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 drivers/net/3c503.c |    2 +-
 drivers/net/e2100.c |    2 +-
 drivers/net/eepro.c |    2 +-
 drivers/net/hp.c    |    2 +-
 kernel/irq/manage.c |    1 +
 5 files changed, 5 insertions(+), 4 deletions(-)

diff -r 0b7e4fbb6238 drivers/net/3c503.c
--- a/drivers/net/3c503.c	Thu Jan 17 15:49:34 2008 +1100
+++ b/drivers/net/3c503.c	Thu Jan 17 16:40:28 2008 +1100
@@ -379,7 +379,7 @@ el2_open(struct net_device *dev)
 
 	outb(EGACFR_NORM, E33G_GACFR);	/* Enable RAM and interrupts. */
 	do {
-	    if (request_irq (*irqp, NULL, 0, "bogus", dev) != -EBUSY) {
+	    if (can_request_irq(*irqp, 0)) {
 		/* Twinkle the interrupt, and check if it's seen. */
 		unsigned long cookie = probe_irq_on();
 		outb_p(0x04 << ((*irqp == 9) ? 2 : *irqp), E33G_IDCFR);
diff -r 0b7e4fbb6238 drivers/net/e2100.c
--- a/drivers/net/e2100.c	Thu Jan 17 15:49:34 2008 +1100
+++ b/drivers/net/e2100.c	Thu Jan 17 16:40:28 2008 +1100
@@ -202,7 +202,7 @@ static int __init e21_probe1(struct net_
 	if (dev->irq < 2) {
 		int irqlist[] = {15,11,10,12,5,9,3,4}, i;
 		for (i = 0; i < 8; i++)
-			if (request_irq (irqlist[i], NULL, 0, "bogus", NULL) != -EBUSY) {
+			if (can_request_irq(irqlist[i], 0)) {
 				dev->irq = irqlist[i];
 				break;
 			}
diff -r 0b7e4fbb6238 drivers/net/eepro.c
--- a/drivers/net/eepro.c	Thu Jan 17 15:49:34 2008 +1100
+++ b/drivers/net/eepro.c	Thu Jan 17 16:40:28 2008 +1100
@@ -914,7 +914,7 @@ static int	eepro_grab_irq(struct net_dev
 
 		eepro_sw2bank0(ioaddr); /* Switch back to Bank 0 */
 
-		if (request_irq (*irqp, NULL, IRQF_SHARED, "bogus", dev) != EBUSY) {
+		if (can_request_irq(*irqp, IRQF_SHARED)) {
 			unsigned long irq_mask;
 			/* Twinkle the interrupt, and check if it's seen */
 			irq_mask = probe_irq_on();
diff -r 0b7e4fbb6238 drivers/net/hp.c
--- a/drivers/net/hp.c	Thu Jan 17 15:49:34 2008 +1100
+++ b/drivers/net/hp.c	Thu Jan 17 16:40:28 2008 +1100
@@ -170,7 +170,7 @@ static int __init hp_probe1(struct net_d
 		int *irqp = wordmode ? irq_16list : irq_8list;
 		do {
 			int irq = *irqp;
-			if (request_irq (irq, NULL, 0, "bogus", NULL) != -EBUSY) {
+			if (can_request_irq(irq, 0)) {
 				unsigned long cookie = probe_irq_on();
 				/* Twinkle the interrupt, and check if it's seen. */
 				outb_p(irqmap[irq] | HP_RUN, ioaddr + HP_CONFIGURE);
diff -r 0b7e4fbb6238 kernel/irq/manage.c
--- a/kernel/irq/manage.c	Thu Jan 17 15:49:34 2008 +1100
+++ b/kernel/irq/manage.c	Thu Jan 17 16:40:28 2008 +1100
@@ -252,6 +252,7 @@ int can_request_irq(unsigned int irq, un
 
 	return !action;
 }
+EXPORT_SYMBOL(can_request_irq);
 
 void compat_irq_chip_set_default_handler(struct irq_desc *desc)
 {

[PATCH] BUG_ON() bad input to request_irq

[Rusty Russell]

Is there any reason why these bugs should be treated gently?  The
caller might not want to check NR_IRQS and IRQ_NOREQUEST cases, but
a NULL handler or NULL dev_id w/ shared are coding bugs.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 kernel/irq/manage.c |    7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff -r c2eb8ef5a0be kernel/irq/manage.c
--- a/kernel/irq/manage.c	Thu Jan 17 15:48:03 2008 +1100
+++ b/kernel/irq/manage.c	Thu Jan 17 15:49:33 2008 +1100
@@ -532,13 +532,12 @@ int request_irq(unsigned int irq, irq_ha
 	 * which interrupt is which (messes up the interrupt freeing
 	 * logic etc).
 	 */
-	if ((irqflags & IRQF_SHARED) && !dev_id)
-		return -EINVAL;
+	BUG_ON((irqflags & IRQF_SHARED) && !dev_id);
+	BUG_ON(!handler);
+
 	if (irq >= NR_IRQS)
 		return -EINVAL;
 	if (irq_desc[irq].status & IRQ_NOREQUEST)
-		return -EINVAL;
-	if (!handler)
 		return -EINVAL;
 
 	action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC);

Re: [PATCH] BUG_ON() bad input to request_irq

[Andrew Morton]

> On Thu, 17 Jan 2008 17:59:58 +1100 Rusty Russell <rusty@rustcorp.com.au> wrote:
> Is there any reason why these bugs should be treated gently?  The
> caller might not want to check NR_IRQS and IRQ_NOREQUEST cases, but
> a NULL handler or NULL dev_id w/ shared are coding bugs.
> 
> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
> ---
>  kernel/irq/manage.c |    7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff -r c2eb8ef5a0be kernel/irq/manage.c
> --- a/kernel/irq/manage.c	Thu Jan 17 15:48:03 2008 +1100
> +++ b/kernel/irq/manage.c	Thu Jan 17 15:49:33 2008 +1100
> @@ -532,13 +532,12 @@ int request_irq(unsigned int irq, irq_ha
>  	 * which interrupt is which (messes up the interrupt freeing
>  	 * logic etc).
>  	 */
> -	if ((irqflags & IRQF_SHARED) && !dev_id)
> -		return -EINVAL;
> +	BUG_ON((irqflags & IRQF_SHARED) && !dev_id);
> +	BUG_ON(!handler);
> +
>  	if (irq >= NR_IRQS)
>  		return -EINVAL;
>  	if (irq_desc[irq].status & IRQ_NOREQUEST)
> -		return -EINVAL;
> -	if (!handler)
>  		return -EINVAL;
>  
>  	action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC);

If no driver is passing in args which will trigger this BUG, we presumably
don't need the patch.

If some driver _is_ passing in ags which will trigger these BUGs then it is
presumably working OK anyway.  Taking a working system and making it go BUG
is likely to upset people.

IOW: WARN_ON, please.

Re: [PATCH] BUG_ON() bad input to request_irq

[Rusty Russell]

On Thursday 24 January 2008 09:04:14 Andrew Morton wrote:
> > On Thu, 17 Jan 2008 17:59:58 +1100 Rusty Russell <rusty@rustcorp.com.au>
> If no driver is passing in args which will trigger this BUG, we presumably
> don't need the patch.

You're only thinking of current code.  The BUG catches future changes, too.

> If some driver _is_ passing in args which will trigger these BUGs then it is
> presumably working OK anyway.  Taking a working system and making it go BUG
> is likely to upset people.

That's why I did the audit.  See patch below which preceeded it, which Jeff
hasn't responded to.  Breaking his drivers might make him notice :)

> IOW: WARN_ON, please.

At end of cycles, sure, but not for 2.6.25: they're even more invisible than
deprecated warnings :(

Rusty.
===
request_irq() always returns -EINVAL with a NULL handler.

I assume that these ancient network drivers were trying to find out if
an irq is available.  eepro.c expecting +EBUSY was doubly wrong.

Request_irq should BUG() on bad input, and these would have been found
earlier.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 drivers/net/3c503.c |    2 +-
 drivers/net/e2100.c |    2 +-
 drivers/net/eepro.c |    2 +-
 drivers/net/hp.c    |    2 +-
 kernel/irq/manage.c |    1 +
 5 files changed, 5 insertions(+), 4 deletions(-)

diff -r 0b7e4fbb6238 drivers/net/3c503.c
--- a/drivers/net/3c503.c	Thu Jan 17 15:49:34 2008 +1100
+++ b/drivers/net/3c503.c	Thu Jan 17 16:40:28 2008 +1100
@@ -379,7 +379,7 @@ el2_open(struct net_device *dev)
 
 	outb(EGACFR_NORM, E33G_GACFR);	/* Enable RAM and interrupts. */
 	do {
-	    if (request_irq (*irqp, NULL, 0, "bogus", dev) != -EBUSY) {
+	    if (can_request_irq(*irqp, 0)) {
 		/* Twinkle the interrupt, and check if it's seen. */
 		unsigned long cookie = probe_irq_on();
 		outb_p(0x04 << ((*irqp == 9) ? 2 : *irqp), E33G_IDCFR);
diff -r 0b7e4fbb6238 drivers/net/e2100.c
--- a/drivers/net/e2100.c	Thu Jan 17 15:49:34 2008 +1100
+++ b/drivers/net/e2100.c	Thu Jan 17 16:40:28 2008 +1100
@@ -202,7 +202,7 @@ static int __init e21_probe1(struct net_
 	if (dev->irq < 2) {
 		int irqlist[] = {15,11,10,12,5,9,3,4}, i;
 		for (i = 0; i < 8; i++)
-			if (request_irq (irqlist[i], NULL, 0, "bogus", NULL) != -EBUSY) {
+			if (can_request_irq(irqlist[i], 0)) {
 				dev->irq = irqlist[i];
 				break;
 			}
diff -r 0b7e4fbb6238 drivers/net/eepro.c
--- a/drivers/net/eepro.c	Thu Jan 17 15:49:34 2008 +1100
+++ b/drivers/net/eepro.c	Thu Jan 17 16:40:28 2008 +1100
@@ -914,7 +914,7 @@ static int	eepro_grab_irq(struct net_dev
 
 		eepro_sw2bank0(ioaddr); /* Switch back to Bank 0 */
 
-		if (request_irq (*irqp, NULL, IRQF_SHARED, "bogus", dev) != EBUSY) {
+		if (can_request_irq(*irqp, IRQF_SHARED)) {
 			unsigned long irq_mask;
 			/* Twinkle the interrupt, and check if it's seen */
 			irq_mask = probe_irq_on();
diff -r 0b7e4fbb6238 drivers/net/hp.c
--- a/drivers/net/hp.c	Thu Jan 17 15:49:34 2008 +1100
+++ b/drivers/net/hp.c	Thu Jan 17 16:40:28 2008 +1100
@@ -170,7 +170,7 @@ static int __init hp_probe1(struct net_d
 		int *irqp = wordmode ? irq_16list : irq_8list;
 		do {
 			int irq = *irqp;
-			if (request_irq (irq, NULL, 0, "bogus", NULL) != -EBUSY) {
+			if (can_request_irq(irq, 0)) {
 				unsigned long cookie = probe_irq_on();
 				/* Twinkle the interrupt, and check if it's seen. */
 				outb_p(irqmap[irq] | HP_RUN, ioaddr + HP_CONFIGURE);
diff -r 0b7e4fbb6238 kernel/irq/manage.c
--- a/kernel/irq/manage.c	Thu Jan 17 15:49:34 2008 +1100
+++ b/kernel/irq/manage.c	Thu Jan 17 16:40:28 2008 +1100
@@ -252,6 +252,7 @@ int can_request_irq(unsigned int irq, un
 
 	return !action;
 }
+EXPORT_SYMBOL(can_request_irq);
 
 void compat_irq_chip_set_default_handler(struct irq_desc *desc)
 {

Re: [PATCH] request_irq() always returns -EINVAL with a NULL handler.

[Stephen Hemminger]

On Thu, 17 Jan 2008 17:57:58 +1100
Rusty Russell <rusty@rustcorp.com.au> wrote:

> I assume that these ancient network drivers were trying to find out if
> an irq is available.  eepro.c expecting +EBUSY was doubly wrong.
> 
> I'm not sure that can_request_irq() is the right thing, but these drivers
> are definitely wrong.
> 
> request_irq should BUG() on bad input, and these would have been found
> earlier.
> 
> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
> ---
>  drivers/net/3c503.c |    2 +-
>  drivers/net/e2100.c |    2 +-
>  drivers/net/eepro.c |    2 +-
>  drivers/net/hp.c    |    2 +-
>  kernel/irq/manage.c |    1 +
>  5 files changed, 5 insertions(+), 4 deletions(-)
> 
> diff -r 0b7e4fbb6238 drivers/net/3c503.c
> --- a/drivers/net/3c503.c	Thu Jan 17 15:49:34 2008 +1100
> +++ b/drivers/net/3c503.c	Thu Jan 17 16:40:28 2008 +1100
> @@ -379,7 +379,7 @@ el2_open(struct net_device *dev)
>  
>  	outb(EGACFR_NORM, E33G_GACFR);	/* Enable RAM and interrupts. */
>  	do {
> -	    if (request_irq (*irqp, NULL, 0, "bogus", dev) != -EBUSY) {
> +	    if (can_request_irq(*irqp, 0)) {
>  		/* Twinkle the interrupt, and check if it's seen. */
>  		unsigned long cookie = probe_irq_on();
>  		outb_p(0x04 << ((*irqp == 9) ? 2 : *irqp), E33G_IDCFR);
> diff -r 0b7e4fbb6238 drivers/net/e2100.c
> --- a/drivers/net/e2100.c	Thu Jan 17 15:49:34 2008 +1100
> +++ b/drivers/net/e2100.c	Thu Jan 17 16:40:28 2008 +1100
> @@ -202,7 +202,7 @@ static int __init e21_probe1(struct net_
>  	if (dev->irq < 2) {
>  		int irqlist[] = {15,11,10,12,5,9,3,4}, i;
>  		for (i = 0; i < 8; i++)
> -			if (request_irq (irqlist[i], NULL, 0, "bogus", NULL) != -EBUSY) {
> +			if (can_request_irq(irqlist[i], 0)) {
>  				dev->irq = irqlist[i];
>  				break;
>  			}
> diff -r 0b7e4fbb6238 drivers/net/eepro.c
> --- a/drivers/net/eepro.c	Thu Jan 17 15:49:34 2008 +1100
> +++ b/drivers/net/eepro.c	Thu Jan 17 16:40:28 2008 +1100
> @@ -914,7 +914,7 @@ static int	eepro_grab_irq(struct net_dev
>  
>  		eepro_sw2bank0(ioaddr); /* Switch back to Bank 0 */
>  
> -		if (request_irq (*irqp, NULL, IRQF_SHARED, "bogus", dev) != EBUSY) {
> +		if (can_request_irq(*irqp, IRQF_SHARED)) {
>  			unsigned long irq_mask;
>  			/* Twinkle the interrupt, and check if it's seen */
>  			irq_mask = probe_irq_on();
> diff -r 0b7e4fbb6238 drivers/net/hp.c
> --- a/drivers/net/hp.c	Thu Jan 17 15:49:34 2008 +1100
> +++ b/drivers/net/hp.c	Thu Jan 17 16:40:28 2008 +1100
> @@ -170,7 +170,7 @@ static int __init hp_probe1(struct net_d
>  		int *irqp = wordmode ? irq_16list : irq_8list;
>  		do {
>  			int irq = *irqp;
> -			if (request_irq (irq, NULL, 0, "bogus", NULL) != -EBUSY) {
> +			if (can_request_irq(irq, 0)) {
>  				unsigned long cookie = probe_irq_on();
>  				/* Twinkle the interrupt, and check if it's seen. */
>  				outb_p(irqmap[irq] | HP_RUN, ioaddr + HP_CONFIGURE);
> diff -r 0b7e4fbb6238 kernel/irq/manage.c
> --- a/kernel/irq/manage.c	Thu Jan 17 15:49:34 2008 +1100
> +++ b/kernel/irq/manage.c	Thu Jan 17 16:40:28 2008 +1100
> @@ -252,6 +252,7 @@ int can_request_irq(unsigned int irq, un
>  
>  	return !action;
>  }
> +EXPORT_SYMBOL(can_request_irq);
>  
>  void compat_irq_chip_set_default_handler(struct irq_desc *desc)
>  {

Isn't this just inherently racy, like the old check_resource stuff that got pulled
out 2.5?

Re: [PATCH] request_irq() always returns -EINVAL with a NULL handler.

[Andrew Morton]

On Thu, 17 Jan 2008 17:57:58 +1100 Rusty Russell <rusty@rustcorp.com.au> wrote:

> I assume that these ancient network drivers were trying to find out if
> an irq is available.  eepro.c expecting +EBUSY was doubly wrong.
> 
> I'm not sure that can_request_irq() is the right thing, but these drivers
> are definitely wrong.
> 
> request_irq should BUG() on bad input, and these would have been found
> earlier.

This breaks non-CONFIG_GENERIC_HARDIRQS architectures.

alpha:

drivers/net/3c503.c: In function 'el2_open':
drivers/net/3c503.c:382: error: implicit declaration of function 'can_request_irq'

Re: [PATCH] request_irq() always returns -EINVAL with a NULL handler.

[Rusty Russell]

On Sunday 03 February 2008 17:15:02 Andrew Morton wrote:
> On Thu, 17 Jan 2008 17:57:58 +1100 Rusty Russell <rusty@rustcorp.com.au> 
wrote:
> > I assume that these ancient network drivers were trying to find out if
> > an irq is available.  eepro.c expecting +EBUSY was doubly wrong.
> >
> > I'm not sure that can_request_irq() is the right thing, but these drivers
> > are definitely wrong.
> >
> > request_irq should BUG() on bad input, and these would have been found
> > earlier.
>
> This breaks non-CONFIG_GENERIC_HARDIRQS architectures.
>
> alpha:
>
> drivers/net/3c503.c: In function 'el2_open':
> drivers/net/3c503.c:382: error: implicit declaration of function
> 'can_request_irq'

Since this code was non-functional before, should we just be removing 
the "check if irq is free" check altogether?

This is Jeff's call, I think.

Rusty.