From 0abb413d12e5e7ca5bc8c5ad9ca8f5a3bc3e6237 Mon Sep 17 00:00:00 2001 From: Qiu-ji Chen Date: Tue, 11 Mar 2025 08:51:19 +0900 Subject: [PATCH] xen: Fix the issue of resource not being properly released in xenbus_dev_probe() BugLink: https://bugs.launchpad.net/bugs/2101915 commit afc545da381ba0c651b2658966ac737032676f01 upstream. This patch fixes an issue in the function xenbus_dev_probe(). In the xenbus_dev_probe() function, within the if (err) branch at line 313, the program incorrectly returns err directly without releasing the resources allocated by err = drv->probe(dev, id). As the return value is non-zero, the upper layers assume the processing logic has failed. However, the probe operation was performed earlier without a corresponding remove operation. Since the probe actually allocates resources, failing to perform the remove operation could lead to problems. To fix this issue, we followed the resource release logic of the xenbus_dev_remove() function by adding a new block fail_remove before the fail_put block. After entering the branch if (err) at line 313, the function will use a goto statement to jump to the fail_remove block, ensuring that the previously acquired resources are correctly released, thus preventing the reference count leak. This bug was identified by an experimental static analysis tool developed by our team. The tool specializes in analyzing reference count operations and detecting potential issues where resources are not properly managed. In this case, the tool flagged the missing release operation as a potential problem, which led to the development of this patch. Fixes: 4bac07c993d0 ("xen: add the Xenbus sysfs and virtual device hotplug driver") Cc: stable@vger.kernel.org Signed-off-by: Qiu-ji Chen Reviewed-by: Juergen Gross Message-ID: <20241105130919.4621-1-chenqiuji666@gmail.com> Signed-off-by: Juergen Gross Signed-off-by: Greg Kroah-Hartman CVE-2024-53198 Signed-off-by: Koichiro Den Signed-off-by: Stefan Bader --- drivers/xen/xenbus/xenbus_probe.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c index 1a9ded0cddcb..25164d56c9d9 100644 --- a/drivers/xen/xenbus/xenbus_probe.c +++ b/drivers/xen/xenbus/xenbus_probe.c @@ -313,7 +313,7 @@ int xenbus_dev_probe(struct device *_dev) if (err) { dev_warn(&dev->dev, "watch_otherend on %s failed.\n", dev->nodename); - return err; + goto fail_remove; } dev->spurious_threshold = 1; @@ -322,6 +322,12 @@ int xenbus_dev_probe(struct device *_dev) dev->nodename); return 0; +fail_remove: + if (drv->remove) { + down(&dev->reclaim_sem); + drv->remove(dev); + up(&dev->reclaim_sem); + } fail_put: module_put(drv->driver.owner); fail: