From a8aec14230322ed8f1e8042b6d656c1631d41163 Mon Sep 17 00:00:00 2001 From: Ira Weiny Date: Fri, 6 Mar 2026 12:33:05 -0600 Subject: [PATCH] nvdimm/bus: Fix potential use after free in asynchronous initialization Dingisoul with KASAN reports a use after free if device_add() fails in nd_async_device_register(). Commit b6eae0f61db2 ("libnvdimm: Hold reference on parent while scheduling async init") correctly added a reference on the parent device to be held until asynchronous initialization was complete. However, if device_add() results in an allocation failure the ref count of the device drops to 0 prior to the parent pointer being accessed. Thus resulting in use after free. The bug bot AI correctly identified the fix. Save a reference to the parent pointer to be used to drop the parent reference regardless of the outcome of device_add(). Reported-by: Dingisoul Closes: http://lore.kernel.org/8855544b-be9e-4153-aa55-0bc328b13733@gmail.com Fixes: b6eae0f61db2 ("libnvdimm: Hold reference on parent while scheduling async init") Cc: stable@vger.kernel.org Reviewed-by: Dave Jiang Link: https://patch.msgid.link/20260306-fix-uaf-async-init-v1-1-a28fd7526723@intel.com Signed-off-by: Ira Weiny --- drivers/nvdimm/bus.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c index bd9621d3f73c..45b7d756e39a 100644 --- a/drivers/nvdimm/bus.c +++ b/drivers/nvdimm/bus.c @@ -486,14 +486,15 @@ EXPORT_SYMBOL_GPL(nd_synchronize); static void nd_async_device_register(void *d, async_cookie_t cookie) { struct device *dev = d; + struct device *parent = dev->parent; if (device_add(dev) != 0) { dev_err(dev, "%s: failed\n", __func__); put_device(dev); } put_device(dev); - if (dev->parent) - put_device(dev->parent); + if (parent) + put_device(parent); } static void nd_async_device_unregister(void *d, async_cookie_t cookie)