From: Keisuke Nishimura Date: Sat, 30 Nov 2024 14:49:53 +0000 (+0100) Subject: KVM: arm64: vgic-its: Add error handling in vgic_its_cache_translation X-Git-Tag: v6.13-rc3~7^2~2^2 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=be7e611274224b23776469d7f7ce50e25ac53142;p=thirdparty%2Fkernel%2Flinux.git KVM: arm64: vgic-its: Add error handling in vgic_its_cache_translation The return value of xa_store() needs to be checked. This fix adds an error handling path that resolves the kref inconsistency on failure. As suggested by Oliver Upton, this function does not return the error code intentionally because the translation cache is best effort. Fixes: 8201d1028caa ("KVM: arm64: vgic-its: Maintain a translation cache per ITS") Signed-off-by: Keisuke Nishimura Suggested-by: Oliver Upton Acked-by: Marc Zyngier Link: https://lore.kernel.org/r/20241130144952.23729-1-keisuke.nishimura@inria.fr Signed-off-by: Oliver Upton --- diff --git a/arch/arm64/kvm/vgic/vgic-its.c b/arch/arm64/kvm/vgic/vgic-its.c index f4c4494645c34..fb96802799c6f 100644 --- a/arch/arm64/kvm/vgic/vgic-its.c +++ b/arch/arm64/kvm/vgic/vgic-its.c @@ -608,12 +608,22 @@ static void vgic_its_cache_translation(struct kvm *kvm, struct vgic_its *its, lockdep_assert_held(&its->its_lock); vgic_get_irq_kref(irq); + old = xa_store(&its->translation_cache, cache_key, irq, GFP_KERNEL_ACCOUNT); + + /* + * Put the reference taken on @irq if the store fails. Intentionally do + * not return the error as the translation cache is best effort. + */ + if (xa_is_err(old)) { + vgic_put_irq(kvm, irq); + return; + } + /* * We could have raced with another CPU caching the same * translation behind our back, ensure we don't leak a * reference if that is the case. */ - old = xa_store(&its->translation_cache, cache_key, irq, GFP_KERNEL_ACCOUNT); if (old) vgic_put_irq(kvm, old); }