[PATCH v2] irqchip/gic-v3-its: Fix potential race condition in its_vlpi_prop_update()

[Hagar Hemdan]

On Fri, May 31, 2024 at 10:27:04AM +0100, Marc Zyngier wrote:
> On Fri, 31 May 2024 08:43:02 +0100,
> Hagar Hemdan <hagarhem at amazon.com> wrote:
> > 
> > its_vlpi_prop_update() calls lpi_write_config() which obtains the
> > mapping information for a VLPI without lock held. So it could race
> > with its_vlpi_unmap().
> > Since all calls from its_irq_set_vcpu_affinity() require the same
> > lock to be held. So instead of peppering the locking all over the
> > place, we hoist the locking into its_irq_set_vcpu_affinity().
> > 
> > This bug was discovered and resolved using Coverity Static Analysis
> > Security Testing (SAST) by Synopsys, Inc.
> > 
> > Fixes: 015ec0386ab6 ("irqchip/gic-v3-its: Add VLPI configuration handling")
> > Signed-off-by: Hagar Hemdan <hagarhem at amazon.com>
> 
> Given that you have lifted both my proposed patch and part of my
> reply as a commit message, you may at least credit me with a
> Suggested-by: tag. Not to mention that the blatant advertising doesn't
> really apply in this case.

ok, I will add this tag in rev3 and we need to add that disclaimer as it is a
commercial tool. thanks!
> 
> > ---
> > v2: moved the lock to its_irq_set_vcpu_affinity().
> > Only compile-tested, no access to HW.
> 
> Was the initial patch tested at all?
No, the initial one was only compile tested, forgot to add that hint in the first
patch.
> 
> 	M.
> 
> -- 
> Without deviation from the norm, progress is not possible.