[PATCH 0/2] xen: fix bugs in error conditions

[PATCH 0/2] xen: fix bugs in error conditions

[Amit Shah]

Hello,

These bugs were found during code review.  Details in the commits.

Please review and apply.

CC: Roger Pau Monné <roger.pau@citrix.com>
CC: David Vrabel <david.vrabel@citrix.com>
CC: Boris Ostrovsky <boris.ostrovsky@oracle.com>
CC: Eduardo Valentin <eduval@amazon.com>
CC: Juergen Gross <jgross@suse.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: "K. Y. Srinivasan" <kys@microsoft.com>
CC: Liu Shuo <shuo.a.liu@intel.com>
CC: Anoob Soman <anoob.soman@citrix.com>


Amit Shah (2):
  xen: fix out-of-bounds irq unbind for MSI message groups
  xen: events: free irqs in error condition

 drivers/xen/events/events_base.c | 2 ++
 1 file changed, 2 insertions(+)

-- 
2.7.3.AMZN

Amazon Development Center Germany GmbH
Berlin - Dresden - Aachen
main office: Krausenstr. 38, 10117 Berlin
Geschaeftsfuehrer: Dr. Ralf Herbrich, Christian Schlaeger
Ust-ID: DE289237879
Eingetragen am Amtsgericht Charlottenburg HRB 149173 B

[PATCH 1/2] xen: fix out-of-bounds irq unbind for MSI message groups

[Amit Shah]

When an MSI descriptor was not available, the error path would try to
unbind an irq that was never acquired - potentially unbinding an
unrelated irq.

Fixes: 4892c9b4ada9f9 ("xen: add support for MSI message groups")
Reported-by: Hooman Mirhadi <mirhadih@amazon.com>
CC: <stable@vger.kernel.org>
CC: Roger Pau Monné <roger.pau@citrix.com>
CC: David Vrabel <david.vrabel@citrix.com>
CC: Boris Ostrovsky <boris.ostrovsky@oracle.com>
CC: Eduardo Valentin <eduval@amazon.com>
CC: Juergen Gross <jgross@suse.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: "K. Y. Srinivasan" <kys@microsoft.com>
CC: Liu Shuo <shuo.a.liu@intel.com>
CC: Anoob Soman <anoob.soman@citrix.com>
Signed-off-by: Amit Shah <aams@amazon.com>
---
 drivers/xen/events/events_base.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index 1ab4bd1..b6b8b29 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -749,6 +749,7 @@ int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
 	}
 
 	ret = irq_set_msi_desc(irq, msidesc);
+	i--;
 	if (ret < 0)
 		goto error_irq;
 out:
-- 
2.7.3.AMZN

Amazon Development Center Germany GmbH
Berlin - Dresden - Aachen
main office: Krausenstr. 38, 10117 Berlin
Geschaeftsfuehrer: Dr. Ralf Herbrich, Christian Schlaeger
Ust-ID: DE289237879
Eingetragen am Amtsgericht Charlottenburg HRB 149173 B

Re: [PATCH 1/2] xen: fix out-of-bounds irq unbind for MSI message groups

[Boris Ostrovsky]

On 02/26/2018 12:36 PM, Amit Shah wrote:
> When an MSI descriptor was not available, the error path would try to
> unbind an irq that was never acquired - potentially unbinding an
> unrelated irq.
>
> Fixes: 4892c9b4ada9f9 ("xen: add support for MSI message groups")
> Reported-by: Hooman Mirhadi <mirhadih@amazon.com>
> CC: <stable@vger.kernel.org>
> CC: Roger Pau Monné <roger.pau@citrix.com>
> CC: David Vrabel <david.vrabel@citrix.com>
> CC: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> CC: Eduardo Valentin <eduval@amazon.com>
> CC: Juergen Gross <jgross@suse.com>
> CC: Thomas Gleixner <tglx@linutronix.de>
> CC: "K. Y. Srinivasan" <kys@microsoft.com>
> CC: Liu Shuo <shuo.a.liu@intel.com>
> CC: Anoob Soman <anoob.soman@citrix.com>
> Signed-off-by: Amit Shah <aams@amazon.com>
> ---
>  drivers/xen/events/events_base.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
> index 1ab4bd1..b6b8b29 100644
> --- a/drivers/xen/events/events_base.c
> +++ b/drivers/xen/events/events_base.c
> @@ -749,6 +749,7 @@ int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
>  	}
>  
>  	ret = irq_set_msi_desc(irq, msidesc);
> +	i--;
>  	if (ret < 0)
>  		goto error_irq;

We really only need to do this in case of an error.

(And this patch needs to go to stable trees as well.)

Thanks
-boris

[PATCH 2/2] xen: events: free irqs in error condition

[Amit Shah]

In case of errors in irq setup for MSI, free up the allocated irqs.

Fixes: 4892c9b4ada9f9 ("xen: add support for MSI message groups")
Reported-by: Hooman Mirhadi <mirhadih@amazon.com>
CC: <stable@vger.kernel.org>
CC: Roger Pau Monné <roger.pau@citrix.com>
CC: David Vrabel <david.vrabel@citrix.com>
CC: Boris Ostrovsky <boris.ostrovsky@oracle.com>
CC: Eduardo Valentin <eduval@amazon.com>
CC: Juergen Gross <jgross@suse.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: "K. Y. Srinivasan" <kys@microsoft.com>
CC: Liu Shuo <shuo.a.liu@intel.com>
CC: Anoob Soman <anoob.soman@citrix.com>
Signed-off-by: Amit Shah <aams@amazon.com>
---
 drivers/xen/events/events_base.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index b6b8b29..96aa575 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -758,6 +758,7 @@ int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
 error_irq:
 	for (; i >= 0; i--)
 		__unbind_from_irq(irq + i);
+	xen_free_irq(irq);
 	mutex_unlock(&irq_mapping_update_lock);
 	return ret;
 }
-- 
2.7.3.AMZN

Amazon Development Center Germany GmbH
Berlin - Dresden - Aachen
main office: Krausenstr. 38, 10117 Berlin
Geschaeftsfuehrer: Dr. Ralf Herbrich, Christian Schlaeger
Ust-ID: DE289237879
Eingetragen am Amtsgericht Charlottenburg HRB 149173 B

Re: [PATCH 2/2] xen: events: free irqs in error condition

[Roger Pau Monné]

On Mon, Feb 26, 2018 at 05:36:35PM +0000, Amit Shah wrote:
> In case of errors in irq setup for MSI, free up the allocated irqs.
> 
> Fixes: 4892c9b4ada9f9 ("xen: add support for MSI message groups")
> Reported-by: Hooman Mirhadi <mirhadih@amazon.com>
> CC: <stable@vger.kernel.org>
> CC: Roger Pau Monné <roger.pau@citrix.com>
> CC: David Vrabel <david.vrabel@citrix.com>
> CC: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> CC: Eduardo Valentin <eduval@amazon.com>
> CC: Juergen Gross <jgross@suse.com>
> CC: Thomas Gleixner <tglx@linutronix.de>
> CC: "K. Y. Srinivasan" <kys@microsoft.com>
> CC: Liu Shuo <shuo.a.liu@intel.com>
> CC: Anoob Soman <anoob.soman@citrix.com>
> Signed-off-by: Amit Shah <aams@amazon.com>
> ---
>  drivers/xen/events/events_base.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
> index b6b8b29..96aa575 100644
> --- a/drivers/xen/events/events_base.c
> +++ b/drivers/xen/events/events_base.c
> @@ -758,6 +758,7 @@ int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
>  error_irq:
>  	for (; i >= 0; i--)
>  		__unbind_from_irq(irq + i);
> +	xen_free_irq(irq);

Hm, xen_free_irq calls irq_free_desc, which is irq_free_descs(irq, 1),
I think you will have to introduce a new free function:

xen_free_irqs(unsigned irq, unsigned int nr)

That calls irq_free_descs(irq, nr)

Thanks, Roger.

Re: [PATCH 2/2] xen: events: free irqs in error condition

[Shah, Amit]

On Mo, 2018-02-26 at 18:14 +0000, Roger Pau Monné wrote:
> On Mon, Feb 26, 2018 at 05:36:35PM +0000, Amit Shah wrote:
> > 
> > In case of errors in irq setup for MSI, free up the allocated irqs.
> > 
> > Fixes: 4892c9b4ada9f9 ("xen: add support for MSI message groups")
> > Reported-by: Hooman Mirhadi <mirhadih@amazon.com>
> > CC: <stable@vger.kernel.org>
> > CC: Roger Pau Monné <roger.pau@citrix.com>
> > CC: David Vrabel <david.vrabel@citrix.com>
> > CC: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> > CC: Eduardo Valentin <eduval@amazon.com>
> > CC: Juergen Gross <jgross@suse.com>
> > CC: Thomas Gleixner <tglx@linutronix.de>
> > CC: "K. Y. Srinivasan" <kys@microsoft.com>
> > CC: Liu Shuo <shuo.a.liu@intel.com>
> > CC: Anoob Soman <anoob.soman@citrix.com>
> > Signed-off-by: Amit Shah <aams@amazon.com>
> > ---
> >  drivers/xen/events/events_base.c | 1 +
> >  1 file changed, 1 insertion(+)
> > 
> > diff --git a/drivers/xen/events/events_base.c
> > b/drivers/xen/events/events_base.c
> > index b6b8b29..96aa575 100644
> > --- a/drivers/xen/events/events_base.c
> > +++ b/drivers/xen/events/events_base.c
> > @@ -758,6 +758,7 @@ int xen_bind_pirq_msi_to_irq(struct pci_dev
> > *dev, struct msi_desc *msidesc,
> >  error_irq:
> >  	for (; i >= 0; i--)
> >  		__unbind_from_irq(irq + i);
> > +	xen_free_irq(irq);
> Hm, xen_free_irq calls irq_free_desc, which is irq_free_descs(irq,
> 1),

Er...  right.

> I think you will have to introduce a new free function:
> 
> xen_free_irqs(unsigned irq, unsigned int nr)
> 
> That calls irq_free_descs(irq, nr)

Actually, xen_free_irq() is already done in __unbind_from_irq(), so
this patch is actually wrong and not needed.


				Amit
Amazon Development Center Germany GmbH
Berlin - Dresden - Aachen
main office: Krausenstr. 38, 10117 Berlin
Geschaeftsfuehrer: Dr. Ralf Herbrich, Christian Schlaeger
Ust-ID: DE289237879
Eingetragen am Amtsgericht Charlottenburg HRB 149173 B

Re: [PATCH 2/2] xen: events: free irqs in error condition

[Roger Pau Monné]

On Mon, Feb 26, 2018 at 06:57:03PM +0000, Shah, Amit wrote:
> 
> On Mo, 2018-02-26 at 18:14 +0000, Roger Pau Monné wrote:
> > On Mon, Feb 26, 2018 at 05:36:35PM +0000, Amit Shah wrote:
> > > 
> > > In case of errors in irq setup for MSI, free up the allocated irqs.
> > > 
> > > Fixes: 4892c9b4ada9f9 ("xen: add support for MSI message groups")
> > > Reported-by: Hooman Mirhadi <mirhadih@amazon.com>
> > > CC: <stable@vger.kernel.org>
> > > CC: Roger Pau Monné <roger.pau@citrix.com>
> > > CC: David Vrabel <david.vrabel@citrix.com>
> > > CC: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> > > CC: Eduardo Valentin <eduval@amazon.com>
> > > CC: Juergen Gross <jgross@suse.com>
> > > CC: Thomas Gleixner <tglx@linutronix.de>
> > > CC: "K. Y. Srinivasan" <kys@microsoft.com>
> > > CC: Liu Shuo <shuo.a.liu@intel.com>
> > > CC: Anoob Soman <anoob.soman@citrix.com>
> > > Signed-off-by: Amit Shah <aams@amazon.com>
> > > ---
> > >  drivers/xen/events/events_base.c | 1 +
> > >  1 file changed, 1 insertion(+)
> > > 
> > > diff --git a/drivers/xen/events/events_base.c
> > > b/drivers/xen/events/events_base.c
> > > index b6b8b29..96aa575 100644
> > > --- a/drivers/xen/events/events_base.c
> > > +++ b/drivers/xen/events/events_base.c
> > > @@ -758,6 +758,7 @@ int xen_bind_pirq_msi_to_irq(struct pci_dev
> > > *dev, struct msi_desc *msidesc,
> > >  error_irq:
> > >  	for (; i >= 0; i--)
> > >  		__unbind_from_irq(irq + i);
> > > +	xen_free_irq(irq);
> > Hm, xen_free_irq calls irq_free_desc, which is irq_free_descs(irq,
> > 1),
> 
> Er...  right.
> 
> > I think you will have to introduce a new free function:
> > 
> > xen_free_irqs(unsigned irq, unsigned int nr)
> > 
> > That calls irq_free_descs(irq, nr)
> 
> Actually, xen_free_irq() is already done in __unbind_from_irq(), so
> this patch is actually wrong and not needed.

You still need to free unbound IRQs, AFAICT you could fix the issue
with a single patch, like:

while (nvec--) {
	if (nvec >= i)
		xen_free_irq(irq + i);
	else
		__unbind_from_irq(irq + i);
}

Roger.

Re: [PATCH 2/2] xen: events: free irqs in error condition

[Shah, Amit]

On Di, 2018-02-27 at 08:14 +0000, Roger Pau Monné wrote:
> On Mon, Feb 26, 2018 at 06:57:03PM +0000, Shah, Amit wrote:
> > 
> > 
> > On Mo, 2018-02-26 at 18:14 +0000, Roger Pau Monné wrote:
> > > 
> > > On Mon, Feb 26, 2018 at 05:36:35PM +0000, Amit Shah wrote:
> > > > 
> > > > 
> > > > In case of errors in irq setup for MSI, free up the allocated
> > > > irqs.
> > > > 
> > > > Fixes: 4892c9b4ada9f9 ("xen: add support for MSI message
> > > > groups")
> > > > Reported-by: Hooman Mirhadi <mirhadih@amazon.com>
> > > > CC: <stable@vger.kernel.org>
> > > > CC: Roger Pau Monné <roger.pau@citrix.com>
> > > > CC: David Vrabel <david.vrabel@citrix.com>
> > > > CC: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> > > > CC: Eduardo Valentin <eduval@amazon.com>
> > > > CC: Juergen Gross <jgross@suse.com>
> > > > CC: Thomas Gleixner <tglx@linutronix.de>
> > > > CC: "K. Y. Srinivasan" <kys@microsoft.com>
> > > > CC: Liu Shuo <shuo.a.liu@intel.com>
> > > > CC: Anoob Soman <anoob.soman@citrix.com>
> > > > Signed-off-by: Amit Shah <aams@amazon.com>
> > > > ---
> > > >  drivers/xen/events/events_base.c | 1 +
> > > >  1 file changed, 1 insertion(+)
> > > > 
> > > > diff --git a/drivers/xen/events/events_base.c
> > > > b/drivers/xen/events/events_base.c
> > > > index b6b8b29..96aa575 100644
> > > > --- a/drivers/xen/events/events_base.c
> > > > +++ b/drivers/xen/events/events_base.c
> > > > @@ -758,6 +758,7 @@ int xen_bind_pirq_msi_to_irq(struct pci_dev
> > > > *dev, struct msi_desc *msidesc,
> > > >  error_irq:
> > > >  	for (; i >= 0; i--)
> > > >  		__unbind_from_irq(irq + i);
> > > > +	xen_free_irq(irq);
> > > Hm, xen_free_irq calls irq_free_desc, which is
> > > irq_free_descs(irq,
> > > 1),
> > Er...  right.
> > 
> > > 
> > > I think you will have to introduce a new free function:
> > > 
> > > xen_free_irqs(unsigned irq, unsigned int nr)
> > > 
> > > That calls irq_free_descs(irq, nr)
> > Actually, xen_free_irq() is already done in __unbind_from_irq(), so
> > this patch is actually wrong and not needed.
> You still need to free unbound IRQs, AFAICT you could fix the issue
> with a single patch, like:
> 
> while (nvec--) {
> 	if (nvec >= i)
> 		xen_free_irq(irq + i);
> 	else
> 		__unbind_from_irq(irq + i);
> }

Agreed.

However, since these are two different things, I'd still like to
separate out into two patches, and two paths so it's easier to see
what's being done.

Sending v2 in a bit.

    Amit


Amazon Development Center Germany GmbH
Berlin - Dresden - Aachen
main office: Krausenstr. 38, 10117 Berlin
Geschaeftsfuehrer: Dr. Ralf Herbrich, Christian Schlaeger
Ust-ID: DE289237879
Eingetragen am Amtsgericht Charlottenburg HRB 149173 B