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=1794064358; b=bKfMhdJf9n3cPOYtafDG4Tp8ZFlklkxL5QFe+20bH+ikryVGNYZwzQuLdpWBskHChWQG sHLuRkSknWwz8KX1axXOXSU7rxejLkNTBA33S1xlV2hW4UMu6SD5q6/m9EbIZps3vgmL4 iE4CswRiiLki9eR3wTOPcO0z8kwB0rrXLnDonOEzGTMaBuRRIdoDtJps5I+PqKCnAOE2P tYVlmFV8S7ulIpJ220JLQDhNx1X2lMj1CIiZfJLjj3CzrpoKXzdc59Y4XKvMUMekOT7Nx SUgxwsMSnMr4tbQBEaBZB7EteY+LTzmdseesompDpGsGKIuoHoqmKumYGo4lHBpeBlQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794064358; 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=Is8kUUfzlAtWNAuKrnZ/HWViNWJ2ogyxK5c+hsbsv/E=; b=wHHRT5pEHOBqtITcHQ2B62ML0xAEfbDccNnS9FgNQ0CNcjd09AXvYv1pAUr5SpnJux16 wVOdpuzRXH04mprh3XnGnt77Cp9b+gV4tlGkGDFTBuZ8xDV6vGV5m4Nc+d3WLvr/MSlZE jx/56b/TrHzOYhRBt+BhmY+WsZdEAFF9HLmuc/99jQ1VFTZa1gZ4t2n0PX6vAfT0dPRVp GY4nkmhBOfnHZFKZrsd9CsS93z8u1tJcid03Ns8U6+JiK1M6muUwGC+fJ212E867ljorz i2k+fUQg44VlTCBfGBuCZasCokCytBFYAwGz/BJEvTeeosXEM1aAjerH8M7ks3kWEVQ== 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=v+7L+TKF; 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 3D31F606B88E; Sat, 7 Nov 2026 15:12:38 +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=v+7L+TKF Received: by smtp.kernel.org (Postfix) with ESMTPSA id E10431F0089F; Sat, 7 Nov 2026 15:12:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794064358; bh=Is8kUUfzlAtWNAuKrnZ/HWViNWJ2ogyxK5c+hsbsv/E=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=v+7L+TKFWoA4bpgRRFAjNblI2I4mr2JDP0tQXtaPh8e3FEW756imeptGYRxzSaM8g 6qNqHvIAW/bsuvlh3/39bFPP/4f0eKW/XyBndUFJCBqSxOICc2EwCkCviptcBtjzUt x0Z2SJ5HQSSGzxb2c6yUa+iEXW5zQaHcGmkgsnnU= 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 7.3 0440/1257] KVM: arm64: vgic-v3: Undo assignment on iodev registration failure Date: Sat, 7 Nov 2026 08:45:36 -0500 Message-ID: <20261107134951.638950422@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134939.434104957@linuxfoundation.org> References: <20261107134939.434104957@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 7.3-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 5913a20d83019..8fb0a3eb3457d 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