From: Marc Zyngier <maz@kernel.org>
To: Karl Mehltretter <kmehltretter@gmail.com>
Cc: Oliver Upton <oupton@kernel.org>,
kvmarm@lists.linux.dev, Fuad Tabba <tabba@google.com>,
Joey Gouly <joey.gouly@arm.com>,
Steffen Eiden <seiden@linux.ibm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Zenghui Yu <yuzenghui@huawei.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Shuah Khan <shuah@kernel.org>, Eric Auger <eric.auger@redhat.com>,
Christoffer Dall <christoffer.dall@arm.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
linux-kselftest@vger.kernel.org
Subject: Re: [PATCH v2 3/5] KVM: arm64: vgic-v3: Unregister redistributors before freeing regions
Date: Sat, 22 Aug 2026 09:40:28 +0100 [thread overview]
Message-ID: <86tsom4kg3.wl-maz@kernel.org> (raw)
In-Reply-To: <aoiiHw4hBHB7C5uL@gmail.com>
On Fri, 21 Aug 2026 20:09:32 +0100,
Karl Mehltretter <kmehltretter@gmail.com> wrote:
>
> On Thu, Aug 20, 2026 at 09:58:57AM +0100, Marc Zyngier wrote:
> > The other bit of interest is in __kvm_vgic_vcpu_destroy(), and its
> > conditional removal of the RD iodevs. Can't we just get rid of this
> > whole block altogether now that we have a saner failing path?
>
> I tested removing that block.
> It reintroduces the use-after-free fixed by ae8f8b376102
> (“KVM: arm64: Unregister redistributor for failed vCPU creation”).
At the very least:
vgic_cpu->rd_iodev.base_addr = VGIC_ADDR_UNDEF;
should be removed, as it serves no purpose anymore: all vcpus, valid
or not, should now go through vgic_unregister_redist_iodev() which
resets the value. It isn't massively useful on teardown anyway, so you
might as well kill the extra one.
M.
--
Without deviation from the norm, progress is not possible.
next prev parent reply other threads:[~2026-08-22 8:40 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-19 22:42 [PATCH v2 0/5] KVM: arm64: fix VGICv3 redistributor rollback Karl Mehltretter
2026-08-19 22:42 ` [PATCH v2 1/5] KVM: arm64: vgic-v3: Undo assignment on iodev registration failure Karl Mehltretter
2026-08-19 22:54 ` sashiko-bot
2026-08-19 22:42 ` [PATCH v2 2/5] KVM: arm64: vgic-v3: Reset assignments after failed region setup Karl Mehltretter
2026-08-19 22:58 ` sashiko-bot
2026-08-19 22:42 ` [PATCH v2 3/5] KVM: arm64: vgic-v3: Unregister redistributors before freeing regions Karl Mehltretter
2026-08-20 8:58 ` Marc Zyngier
2026-08-21 19:09 ` Karl Mehltretter
2026-08-22 8:40 ` Marc Zyngier [this message]
2026-08-19 22:42 ` [PATCH v2 4/5] KVM: arm64: selftests: Pass guest code to vm_gic_create_with_vcpus() Karl Mehltretter
2026-08-19 22:50 ` sashiko-bot
2026-08-19 22:42 ` [PATCH v2 5/5] KVM: arm64: selftests: Test VGICv3 redistributor region retry Karl Mehltretter
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