From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B14AD503BDA; Wed, 30 Sep 2026 16:20:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790785265; cv=none; b=toT5w8UFrnnxXZyT6sSjJkJ08RwBmQBoKIpQlpyWfNXAscuaf13SrmGytNxv4ns8WI/iswJo3IcHZ0klqyRgDLAY9wR+unluvD+zUGAkqGaA107yaKp8LB71tLxVndmLg87Jc81FxxJ0MLN3AeOIwSwS/xARNXFYVn2XjwapZhQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790785265; c=relaxed/simple; bh=650VYKvvdVCuYCxzyiJD34mRsT+XEaRk9REKNNQZTwg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NmQ2vDQ2pSOWNbtloTWSt/R9URc09nqYAeJSLXusofwRSSqBbMgyih6fwrv16CtTjveXAzRqZBRBtK++1ygTY9Ky8XBv0C5wIYbZXQHIycLwN/mEhDrqmoyf89YXYTXcC6Dg9o7Ys/qaY9utkjG6HAY1mwjqdl+iTCUd3RdTMlU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=NyLWkbhD; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="NyLWkbhD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 90B761F000FF; Wed, 30 Sep 2026 16:20:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790785257; bh=iivw1xHJj2tCOcMhHEPV+mCRfAxkyQP5GM1TmghqMb4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=NyLWkbhDHwMQ+eu00euNIjIKm/NotB8y7wzL+eFya9EkVcQLx5XCxXR6usAuN4td4 F5mC1VqEmkD5u7OuYJWg3zrGUJd1KM6taghHDaNSMi6f4QD6iF2I4qOtgvG7gpQYIV L25NgB+wvN1DfMHxRFC07+U9W+BIXOzvQmjIAEuY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Michael S. Tsirkin" , Andrew Stellman , Sasha Levin Subject: [PATCH 6.1 443/982] virtio-pci: return IRQ_HANDLED after non-zero ISR Date: Wed, 30 Sep 2026 17:19:39 +0200 Message-ID: <20260930152426.308462321@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152416.775402466@linuxfoundation.org> References: <20260930152416.775402466@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Andrew Stellman [ Upstream commit 93fa09455fb1a9624b73d42ac1f83771f4818e80 ] vp_interrupt() reads the ISR before dispatching config-change and vring handling. Reading the ISR also clears it, so once the read returns non-zero the interrupt was from this device and has already been consumed. Currently vp_interrupt() returns the result of vp_vring_interrupt(). For a config-change interrupt with no vring work, that can return IRQ_NONE even though the ISR was non-zero and the interrupt was handled. Call vp_vring_interrupt() for any queue work, but once the ISR is non-zero return IRQ_HANDLED. Tested with QEMU virtio-blk-pci forced to INTx using vectors=0 and pci=nomsi. On an idle device, 200 config-change interrupts were generated using QMP block_resize. Before this change, irq_handler_exit reported ret=unhandled and /proc/irq/11/spurious increased from 0 to 200 unhandled interrupts. After this change, irq_handler_exit reported ret=handled and the unhandled count remained at 0. The issue was found during an LLM-assisted Quality Playbook review. Fixes: 77cf524654a8 ("virtio_pci: split up vp_interrupt") Suggested-by: Michael S. Tsirkin Assisted-by: LLM Signed-off-by: Andrew Stellman Message-ID: <20260904141318.30278-1-astellman@stellman-greene.com> Signed-off-by: Michael S. Tsirkin Signed-off-by: Sasha Levin --- drivers/virtio/virtio_pci_common.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c index 6bfb67d4866c3..578806c4c2ae1 100644 --- a/drivers/virtio/virtio_pci_common.c +++ b/drivers/virtio/virtio_pci_common.c @@ -96,7 +96,9 @@ static irqreturn_t vp_interrupt(int irq, void *opaque) if (isr & VIRTIO_PCI_ISR_CONFIG) vp_config_changed(irq, opaque); - return vp_vring_interrupt(irq, opaque); + vp_vring_interrupt(irq, opaque); + + return IRQ_HANDLED; } static int vp_request_msix_vectors(struct virtio_device *vdev, int nvectors, -- 2.53.0