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=1794312769; b=nlf/W8kYflN2kAUEewaPMgWCJKQlYG00RdpxueL3H7P/G0yS9gj3/uFZPjLzQUDxDfqA Uur037WQL1ovfCjHyvQMcZYpL7poroGgHjE1yg+7Yh6F81O7sF5Pwqddo4iPO+M0dKoEm nRsPpwbaJTRY5i6zCVk5qI0DSu2nEj7Gj0HNnxBM/Nvrfs+S9/87q6yKqNJRSPV6GG7n1 Y80oHRLPsZwQDEnHHV8q4GjmLwq94LH2HLD7JF4s+S844Ppnc6CCsKuT5Sd3p5M5+SfOw 6akFxrMTotKBH68gTDNCgKFn55IfBTMi6eEqyxZWa4temAm96jTaGPrzj2/ncrcuuBg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794312769; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=Ll02ezm7Fpp+RmTiiEGTwTmsRI6ygI6F6NsEEHAdjvU=; b=Yvmk7Yi0IkfTeBNAxtH/+fGOHFg6GgnyjOAWKOKBnAK1CqB6KoCgTa35a3ovZa2Cew+X aHPw1p7o025iQuyJMGQePFxKJO8Mk7JhvUQjfhYcQR9v8ml4U0JqgACOEgbaKP7XJqi2X 3VqrjhtBOpjefV8cPRJcL+bbE4+/54tyhnkDD/jBEkBBA/8iQJGBy3dO9xsWgLjaZPzSG e/Hn2cfj3ADaV1P4bhWQHV6zr9E8tNkbEHcFI0ky/O7bVwDF/gjj1M7Bdp0xRT6qCl3TX 9w0dl4G5FKwV5myqvbq0RDgiFMbxexEOeFhlkiGr03yN+mi+8c+H2zA/aBFNWFLNjNA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=m8t5ZhVd; 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 A806E606A31C for ; Tue, 10 Nov 2026 12:12:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=m8t5ZhVd Received: by smtp.kernel.org (Postfix) with ESMTPSA id E46FA1F0089F; Tue, 10 Nov 2026 12:12:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794312768; bh=Ll02ezm7Fpp+RmTiiEGTwTmsRI6ygI6F6NsEEHAdjvU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=m8t5ZhVdBUJT3AhJBE3ePD5GFjW6LY9RtpO7ZfELDxu2uybNW7tkFbmio44EAe8/j uUybu/dOHuKcqB3x4iQkb7dPnpfKSofohMITDLYjj2cYB/oCMpr/ael32TXNAC+RsU y371hCTHkFi9dLHTgG29cgcgxXTY1qZlsj12dm+u3WTe8yJSILyw6iAkQQAB4t8ylB 2nZPF33KH2cCpAqUZIKwQ4GEMVEvkss90CPt2F346Zw17Ty+tKNh7QafVSJM3Zvnnn enMGQKBq4MFIOienwhwVShH6tAsjgqwyT6EQCEyvdOKCqSKt8yLVxhsn3lewtNwZ5/ s9e4Lh9YfS4qw== From: Sasha Levin To: stable@vger.kernel.org Cc: Karl Mehltretter , Fuad Tabba , Marc Zyngier , Sasha Levin Subject: [PATCH 5.10.y] KVM: arm64: vgic-v3: Undo assignment on iodev registration failure Date: Tue, 10 Nov 2026 07:12:46 -0500 Message-ID: <20261110121137.996763-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261107061817-failed-5.10-8a88a46b86ca@kernel.org> References: <20261107061817-failed-5.10-8a88a46b86ca@kernel.org> 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 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 [ sashal: adapted failure cleanup to rely on existing kvm->lock protection instead of a config_lock guard ] Signed-off-by: Sasha Levin --- arch/arm64/kvm/vgic/vgic-mmio-v3.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/arch/arm64/kvm/vgic/vgic-mmio-v3.c b/arch/arm64/kvm/vgic/vgic-mmio-v3.c index 7a6360eba3214..d7c06cf6dc0f9 100644 --- a/arch/arm64/kvm/vgic/vgic-mmio-v3.c +++ b/arch/arm64/kvm/vgic/vgic-mmio-v3.c @@ -731,16 +731,21 @@ 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 kvm->lock */ + rdreg->free_index++; + mutex_lock(&kvm->slots_lock); ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS, rd_base, 2 * SZ_64K, &rd_dev->dev); mutex_unlock(&kvm->slots_lock); - if (ret) - return ret; + if (ret) { + vgic_cpu->rdreg->free_index--; + vgic_cpu->rdreg = NULL; + vgic_cpu->rd_iodev.base_addr = VGIC_ADDR_UNDEF; + } - rdreg->free_index++; - return 0; + return ret; } static void vgic_unregister_redist_iodev(struct kvm_vcpu *vcpu) -- 2.53.0