linux-kernel - [PATCH] virtio-mmio: fix memory leak of vm

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Message-ID: <20230905094228.97125-1-mheyne@amazon.de>
Date:   Tue, 5 Sep 2023 09:42:28 +0000
From:   Maximilian Heyne <mheyne@...zon.de>
To:     unlisted-recipients:; (no To-header on input)
CC:     Maximilian Heyne <mheyne@...zon.de>, <stable@...r.kernel.org>,
        "Michael S. Tsirkin" <mst@...hat.com>,
        Jason Wang <jasowang@...hat.com>,
        Xuan Zhuo <xuanzhuo@...ux.alibaba.com>,
        Wolfram Sang <wsa+renesas@...g-engineering.com>,
        <virtualization@...ts.linux-foundation.org>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH] virtio-mmio: fix memory leak of vm_dev

With the recent removal of vm_dev from devres its memory is only freed
via the callback virtio_mmio_release_dev. However, this only takes
effect after device_add is called by register_virtio_device. Until then
it's an unmanaged resource and must be explicitly freed on error exit.

This bug was discovered and resolved using Coverity Static Analysis
Security Testing (SAST) by Synopsys, Inc.

Cc: stable@...r.kernel.org
Fixes: 55c91fedd03d ("virtio-mmio: don't break lifecycle of vm_dev")
Signed-off-by: Maximilian Heyne <mheyne@...zon.de>
---
Please note that I have only compile tested this code.

 drivers/virtio/virtio_mmio.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index 97760f611295..b2a48d07e973 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -631,13 +631,16 @@ static int virtio_mmio_probe(struct platform_device *pdev)
 	spin_lock_init(&vm_dev->lock);
 
 	vm_dev->base = devm_platform_ioremap_resource(pdev, 0);
-	if (IS_ERR(vm_dev->base))
+	if (IS_ERR(vm_dev->base)) {
+		kfree(vm_dev);
 		return PTR_ERR(vm_dev->base);
+	}
 
 	/* Check magic value */
 	magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE);
 	if (magic != ('v' | 'i' << 8 | 'r' << 16 | 't' << 24)) {
 		dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic);
+		kfree(vm_dev);
 		return -ENODEV;
 	}
 
@@ -646,6 +649,7 @@ static int virtio_mmio_probe(struct platform_device *pdev)
 	if (vm_dev->version < 1 || vm_dev->version > 2) {
 		dev_err(&pdev->dev, "Version %ld not supported!\n",
 				vm_dev->version);
+		kfree(vm_dev);
 		return -ENXIO;
 	}
 
@@ -655,6 +659,7 @@ static int virtio_mmio_probe(struct platform_device *pdev)
 		 * virtio-mmio device with an ID 0 is a (dummy) placeholder
 		 * with no function. End probing now with no error reported.
 		 */
+		kfree(vm_dev);
 		return -ENODEV;
 	}
 	vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID);
-- 
2.40.1




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