Re: [PATCH] x86: ioapic: Fix irq_free_descs count

From: David Rientjes
Date: Mon Jun 30 2014 - 18:19:40 EST


On Mon, 30 Jun 2014, Keith Busch wrote:

> On Mon, 30 Jun 2014, David Rientjes wrote:
> > On Mon, 30 Jun 2014, Keith Busch wrote:
> >
> > > Signed-off-by: Keith Busch <keith.busch@xxxxxxxxx>
> > > Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> > > Cc: x86@xxxxxxxxxx
> >
> > Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
> >
> > This is definitely a fix for "genirq: Provide generic hwirq allocation
> > facility", but the changelog doesn't describe what the problem is and the
> > title that this somehow fixes irq_free_descs() doesn't make any sense.
>
> My mistake, I used the component from the commit I bisected the bug
> down to.
>
> > It's the equivalent of just doing
> >
> > - irq_free_descs(from, cnt);
> > + irq_free_descs(from, i - from);
> >
> > I'd suggest the patch title be changed to
> >
> > genirq: Fix memory leak when calling irq_free_hwirqs()
> >
> > and the changelog state
> >
> > irq_free_hwirqs() always calls irq_free_descs() with a cnt == 0 which
> > makes it a no-op since the interrupt count to free is decremented in
> > itself.
>
> Yes, I like your suggestion. Should I submit a v2, or will maintainer
> replace the changelog?
>

It's an urgent patch since commit 7b6ef1262549 ("genirq: Provide generic
hwirq allocation facility") was already released in 3.15. Unless Thomas
fixes it up first, I'd reply with a v2 with the fixed title and changelog,
add a

Fixes: 7b6ef1262549f6afc5c881aaef80beb8fd15f908

tag along with my acked-by to make his life 0.000000001% easier.
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