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 7AEE236D4E1; Wed, 30 Sep 2026 18:05:25 +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=1790791526; cv=none; b=f5Ig+anJrfiuNZLdjwi7Sp+AXaOLWT8rdWbPJ2NPLlTLl2nad7xtLkdD9CoGuzlX9KtAIUsUZkjFfhRwoteFvRwfHd++jLyICCkF26j4NYGJNY0s3z39GVvuZqjnlHkCjddA1nKaamDRFGhc21KUazOCQRLp5qRIclYvnVpFz3E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790791526; c=relaxed/simple; bh=TkhXJ9jUgg2r7oLfh030Rc2yjVaG86aTfV8nn+zN29c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=RtY81U6FNyZsbRYXecygQahpgGJOZ7rARLnWmmmEM/tCR94hGkLt3EhflUjJmnsFgRoQkMyHFjMFcT/xq9jyphA8UjKZuGO756vbp+1R0E5CznU9Iv2qPKxIFXBccDF73DtTjQoKCUJVVDXkdDQm4c1QZS5Oh8he6ohLl8Rhm94= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=bJFs3Mqk; 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="bJFs3Mqk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D59581F000FF; Wed, 30 Sep 2026 18:05:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790791525; bh=cqrehyGsjDUUSRkqJk+bn2/Ep9kXgZiIIiAGYrbpZ7s=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=bJFs3MqkrFTsErOAyOCstJqayb01SYgxhwXJVrDarESReFcm4marS/3+6fMgCnjn1 wvytFnYNyTsjBrWHNTp2eXJQ45i9u5BEDbVGj9kMZMg7t1HrARrp7ENUlFuEcQmI6j qxqNe4Fe6qAd50a37BQwrXDrYfKvxT2PgRmX/HYc= 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 5.15 334/752] virtio-pci: return IRQ_HANDLED after non-zero ISR Date: Wed, 30 Sep 2026 17:23:24 +0200 Message-ID: <20260930152405.520972658@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152358.131179731@linuxfoundation.org> References: <20260930152358.131179731@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 5.15-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 a6f375417fd54..437622cd079f5 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