| Message ID | 1389386987-26201-1-git-send-email-julien.grall@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
On Fri, 2014-01-10 at 20:49 +0000, Julien Grall wrote: > For now __setup_dt_irq can only fail if the action is already set. Can this ever happen with the current code base? > If in the future, the function is updated we don't want to enable the IRQ. Such an update is likely to be post-4.4 (unless there is a relationship with "IRQ: Protect IRQ to be shared between domains and XEN" AND the RM becomes convinced to grant a freeze exception for that patch). On that basis this patch could also easily be post-4.4. > Assuming the function can fail with action = NULL, when Xen will receive the > IRQ it will segfault because do_IRQ doesn't check if action is NULL. It seems unlikely that the system would be fully functional after such an error even with this patch -- it would have failed to register either timer, maintenance or the console interrupt. > > Signed-off-by: Julien Grall <julien.grall@linaro.org> > --- > xen/arch/arm/gic.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c > index e6257a7..62510e3 100644 > --- a/xen/arch/arm/gic.c > +++ b/xen/arch/arm/gic.c > @@ -605,8 +605,8 @@ int __init setup_dt_irq(const struct dt_irq *irq, struct irqaction *new) > rc = __setup_irq(desc, irq->irq, new); > spin_unlock_irqrestore(&desc->lock, flags); > > - desc->handler->startup(desc); > - > + if ( !rc ) > + desc->handler->startup(desc); > > return rc; > }
On 01/15/2014 01:44 PM, Ian Campbell wrote: > On Fri, 2014-01-10 at 20:49 +0000, Julien Grall wrote: >> For now __setup_dt_irq can only fail if the action is already set. > > Can this ever happen with the current code base? No, that why I didn't ask for a freeze exception for Xen 4.4. > >> If in the future, the function is updated we don't want to enable the IRQ. > > Such an update is likely to be post-4.4 (unless there is a relationship > with "IRQ: Protect IRQ to be shared between domains and XEN" AND the RM > becomes convinced to grant a freeze exception for that patch). > > On that basis this patch could also easily be post-4.4. > >> Assuming the function can fail with action = NULL, when Xen will receive the >> IRQ it will segfault because do_IRQ doesn't check if action is NULL. > > It seems unlikely that the system would be fully functional after such > an error even with this patch -- it would have failed to register either > timer, maintenance or the console interrupt. Timer and maintenance code don't check the return of request_dt_irq (which call setup_dt_irq). For the console interrupt, the callback which initialize the interrupt doesn't return an error... On every serial driver, only an error message is printed. In any case, it's wrong to enable this IRQ if the descriptor is not correctly setup. > >> >> Signed-off-by: Julien Grall <julien.grall@linaro.org> >> --- >> xen/arch/arm/gic.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c >> index e6257a7..62510e3 100644 >> --- a/xen/arch/arm/gic.c >> +++ b/xen/arch/arm/gic.c >> @@ -605,8 +605,8 @@ int __init setup_dt_irq(const struct dt_irq *irq, struct irqaction *new) >> rc = __setup_irq(desc, irq->irq, new); >> spin_unlock_irqrestore(&desc->lock, flags); >> >> - desc->handler->startup(desc); >> - >> + if ( !rc ) >> + desc->handler->startup(desc); >> >> return rc; >> } > >
On Wed, 2014-01-15 at 14:01 +0000, Julien Grall wrote: > On 01/15/2014 01:44 PM, Ian Campbell wrote: > > On Fri, 2014-01-10 at 20:49 +0000, Julien Grall wrote: > >> For now __setup_dt_irq can only fail if the action is already set. > > > > Can this ever happen with the current code base? > > No, that why I didn't ask for a freeze exception for Xen 4.4. Ah ok. It is useful to tag patches which aren't for consideration (and those which are for that matter, although the exception request suffices there). I'll put this in my 4.5 queue and consider it again later. Please ping me a little while after 4.4 branches if I haven't done so.
On 01/15/2014 02:07 PM, Ian Campbell wrote: > On Wed, 2014-01-15 at 14:01 +0000, Julien Grall wrote: >> On 01/15/2014 01:44 PM, Ian Campbell wrote: >>> On Fri, 2014-01-10 at 20:49 +0000, Julien Grall wrote: >>>> For now __setup_dt_irq can only fail if the action is already set. >>> >>> Can this ever happen with the current code base? >> >> No, that why I didn't ask for a freeze exception for Xen 4.4. > > Ah ok. It is useful to tag patches which aren't for consideration (and > those which are for that matter, although the exception request suffices > there). Do you have a specific tag in my mind for this purpose? > I'll put this in my 4.5 queue and consider it again later. Please ping > me a little while after 4.4 branches if I haven't done so. Thanks.
On Wed, 2014-01-15 at 14:08 +0000, Julien Grall wrote: > On 01/15/2014 02:07 PM, Ian Campbell wrote: > > On Wed, 2014-01-15 at 14:01 +0000, Julien Grall wrote: > >> On 01/15/2014 01:44 PM, Ian Campbell wrote: > >>> On Fri, 2014-01-10 at 20:49 +0000, Julien Grall wrote: > >>>> For now __setup_dt_irq can only fail if the action is already set. > >>> > >>> Can this ever happen with the current code base? > >> > >> No, that why I didn't ask for a freeze exception for Xen 4.4. > > > > Ah ok. It is useful to tag patches which aren't for consideration (and > > those which are for that matter, although the exception request suffices > > there). > > Do you have a specific tag in my mind for this purpose? Anything would do, either [PATCH for-4.5] in $subject or: --- This patch is for 4.5 after the commit message etc. Ian.
On 01/15/2014 02:07 PM, Ian Campbell wrote: > > I'll put this in my 4.5 queue and consider it again later. Please ping > me a little while after 4.4 branches if I haven't done so. I plan to send a bigger patch series today on interrupt management for ARM. The patch will be include in this serie. You can remove the patch from your 4.5 queue for now.
diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c index e6257a7..62510e3 100644 --- a/xen/arch/arm/gic.c +++ b/xen/arch/arm/gic.c @@ -605,8 +605,8 @@ int __init setup_dt_irq(const struct dt_irq *irq, struct irqaction *new) rc = __setup_irq(desc, irq->irq, new); spin_unlock_irqrestore(&desc->lock, flags); - desc->handler->startup(desc); - + if ( !rc ) + desc->handler->startup(desc); return rc; }
For now __setup_dt_irq can only fail if the action is already set. If in the future, the function is updated we don't want to enable the IRQ. Assuming the function can fail with action = NULL, when Xen will receive the IRQ it will segfault because do_IRQ doesn't check if action is NULL. Signed-off-by: Julien Grall <julien.grall@linaro.org> --- xen/arch/arm/gic.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)