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From: Andrew Jones <drjones@redhat.com>
To: Nikos Nikoleris <nikos.nikoleris@arm.com>
Cc: kvm@vger.kernel.org, alexandru.elisei@arm.com
Subject: Re: [kvm-unit-tests PATCH 1/4] arm/arm64: Avoid calling cpumask_test_cpu for CPUs above nr_cpu
Date: Mon, 22 Mar 2021 11:53:46 +0100	[thread overview]
Message-ID: <20210322105346.qyfhbyk5szvcc7z2@kamzik.brq.redhat.com> (raw)
In-Reply-To: <d30766b7-97d2-cfd6-cf6a-3799bd9a6fd6@arm.com>

On Mon, Mar 22, 2021 at 10:40:26AM +0000, Nikos Nikoleris wrote:
> 
> Prior to this change, a call of cpumask_next(cpu, mask) where cpu=nr_cpu
> - 1 (assuming all cpus are enumerated in the range 0..nr_cpus - 1) would
> make an out-of-bounds access to the mask. In many cases, this is still a
> valid memory location due the implementation of cpumask_t, however, in
> certain configurations (for example, nr_cpus == sizeof(long)) this would
> cause an access outside the bounds of the mask too.
> 
> This patch changes the way we guard calls to cpumask_test_cpu() in
> cpumask_next() to avoid the above condition. A following change adds
> assertions to catch out-of-bounds accesses to cpumask_t.
> 

Thanks, I've added it. It looks like Alexandru would also like commit
message improvements. I can add those too.

Thanks,
drew


  reply	other threads:[~2021-03-22 10:54 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-19 12:24 [kvm-unit-tests PATCH 0/4] RFC: Minor arm/arm64 MMU fixes and checks Nikos Nikoleris
2021-03-19 12:24 ` [kvm-unit-tests PATCH 1/4] arm/arm64: Avoid calling cpumask_test_cpu for CPUs above nr_cpu Nikos Nikoleris
2021-03-22  9:31   ` Andrew Jones
2021-03-22  9:45     ` Nikos Nikoleris
2021-03-22 10:12       ` Andrew Jones
2021-03-22 10:40         ` Nikos Nikoleris
2021-03-22 10:53           ` Andrew Jones [this message]
2021-03-19 12:24 ` [kvm-unit-tests PATCH 2/4] arm/arm64: Read system registers to get the state of the MMU Nikos Nikoleris
2021-03-22 10:30   ` Alexandru Elisei
2021-03-22 11:14     ` Nikos Nikoleris
2021-03-22 15:25       ` Alexandru Elisei
2021-03-19 12:24 ` [kvm-unit-tests PATCH 3/4] arm/arm64: Track whether thread_info has been initialized Nikos Nikoleris
2021-03-22 10:34   ` Alexandru Elisei
2021-03-22 10:59     ` Nikos Nikoleris
2021-03-22 12:11       ` Andrew Jones
2021-03-19 12:24 ` [kvm-unit-tests PATCH 4/4] arm/arm64: Add sanity checks to the cpumask API Nikos Nikoleris
2021-03-23 11:24 ` [kvm-unit-tests PATCH 0/4] RFC: Minor arm/arm64 MMU fixes and checks Andrew Jones
2021-03-23 11:40   ` Alexandru Elisei
2021-03-23 11:51     ` Andrew Jones
2021-03-23 12:15       ` Nikos Nikoleris

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