From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794063101; b=oDjyb6uglMkr6U7YRi0Bq3TBeKSXMOwAIZbWeO6GCll9U2fv90nuZaXRjUJgXRz99r6F /VETDMJpsWLSIDOdaPmisG/wBXMiBRzYhsDl+FOR/MTacgReTW/TGhzMMRsaydAQAcE1L 0JwnVloGr6wg3z9b9zoeun2Am8ZzVT8lL+5Rv+q9EgN52Kk2R6e99J9kwpxjKtyjcDKM4 3dVVvRfviYe0QvVa1DvdL/RXq/nRZsU4CXs8hr5g0547NwO4+EwDxQDmRcUzIliAB6RWw A2NEILFeR6qJGOcXkTV98UydlG3/uUqG5isa+HXDN6fYsCMCzi5Ovl8HcuC18NR1qKw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794063101; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=w7tkv0Q7ibQdpdNIMefMhkxSZtgTb+FZK0Xe69z+ods=; b=nTtlkaT3JQaGKuBVUTxdqEZOr4XSm8qq1AkdHBaFNEv4r/8+QmkMVL3vhOUHgSzN8whS af12XOcSyfWWDTJfDhCLc6xUSCwRQwOHexsbU8e2eYxSJfKQWySyu9zbj8s05lnara1ey IDBl+siXZbtSSOREBnqDQE9R76HCCqOWb0b8Pis9PXTquqAyP2Tz2zj7+8DVQzx1zDMZG r02rnWgvXAqRvlVUSmLD2O3C9DVUrSL6/oBlrjFc1aOgjtObBC112yVuvU4S26xP2OxjW kNFuvqj1g6L04nTW3mBaLE8QSLn0QgAXRL3g/yi1rkIGW7RwnqZh/b5EKkFisHBM9EA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=JjH9UPxC; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EF999606D804; Sat, 7 Nov 2026 14:51:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=JjH9UPxC Received: by smtp.kernel.org (Postfix) with ESMTPSA id 567EE1F0089F; Sat, 7 Nov 2026 14:51:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794063100; bh=w7tkv0Q7ibQdpdNIMefMhkxSZtgTb+FZK0Xe69z+ods=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=JjH9UPxCoR2tDJKdV3uS/XUmBoQdKs/VRhAZODL1EvptfnifbDPaaXpyARZ90lEEo H08Va98gn25PXgUHFPSVn5hurUkvnGLlB0g1IqAtygEv0ESN5f3rVDhhaexdUSmq3+ o0haWiq+YjNn3GreHbv1vRlaHD3qRZYCXfDD8l44= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Karl Mehltretter , Fuad Tabba , Marc Zyngier , Sasha Levin Subject: [PATCH 6.18 335/869] KVM: arm64: vgic-v3: Undo assignment on iodev registration failure Date: Sat, 7 Nov 2026 08:50:17 -0500 Message-ID: <20261107134903.773462969@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134852.069646174@linuxfoundation.org> References: <20261107134852.069646174@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Karl Mehltretter [ Upstream commit 8a88a46b86ca3dbbd24522760d29edfb3f24ac2a ] vgic_register_redist_iodev() assigns a redistributor region and base address to the vCPU before adding its iodev to the MMIO bus. However, the region's free_index is advanced only after registration succeeds. If kvm_io_bus_register_dev() fails, the vCPU retains the assignment while free_index still identifies the same slot as free. A later registration can therefore reuse a slot that remains assigned to the vCPU. Reserve the slot before registering its iodev. The caller holds slots_lock, so a registration failure cannot race with a later assignment. Undo the reservation and clear the cached assignment on failure. Fixes: dbd9733ab674 ("KVM: arm/arm64: Replace the single rdist region by a list") Cc: stable@vger.kernel.org Assisted-by: Codex:gpt-5.6-sol Signed-off-by: Karl Mehltretter Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba Link: https://patch.msgid.link/20260831081005.41346-2-kmehltretter@gmail.com [maz: moved helper into the sole caller] Signed-off-by: Marc Zyngier Signed-off-by: Sasha Levin --- arch/arm64/kvm/vgic/vgic-mmio-v3.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/arch/arm64/kvm/vgic/vgic-mmio-v3.c b/arch/arm64/kvm/vgic/vgic-mmio-v3.c index 051d9bf73879c..7d90e6fe076c3 100644 --- a/arch/arm64/kvm/vgic/vgic-mmio-v3.c +++ b/arch/arm64/kvm/vgic/vgic-mmio-v3.c @@ -818,16 +818,21 @@ int vgic_register_redist_iodev(struct kvm_vcpu *vcpu) rd_dev->nr_regions = ARRAY_SIZE(vgic_v3_rd_registers); rd_dev->redist_vcpu = vcpu; + /* Protected by slots_lock */ + rdreg->free_index++; + mutex_unlock(&kvm->arch.config_lock); ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS, rd_base, 2 * SZ_64K, &rd_dev->dev); - if (ret) - return ret; + if (ret) { + guard(mutex)(&vcpu->kvm->arch.config_lock); + vgic_cpu->rdreg->free_index--; + vgic_cpu->rdreg = NULL; + vgic_cpu->rd_iodev.base_addr = VGIC_ADDR_UNDEF; + } - /* Protected by slots_lock */ - rdreg->free_index++; - return 0; + return ret; out_unlock: mutex_unlock(&kvm->arch.config_lock); -- 2.53.0