This is a note to let you know that I've just added the patch titled fpga: bridge: properly initialize bridge device before populating children to the 6.1-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: fpga-bridge-properly-initialize-bridge-device-before-populating-children.patch and it can be found in the queue-6.1 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From dc70eb868b9cd2ca01313e5a394e6ea001d513e9 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Alexis=20Lothor=C3=A9?= <alexis.lothore@xxxxxxxxxxx> Date: Tue, 4 Apr 2023 15:31:02 +0200 Subject: fpga: bridge: properly initialize bridge device before populating children MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Alexis Lothoré <alexis.lothore@xxxxxxxxxxx> commit dc70eb868b9cd2ca01313e5a394e6ea001d513e9 upstream. The current code path can lead to warnings because of uninitialized device, which contains, as a consequence, uninitialized kobject. The uninitialized device is passed to of_platform_populate, which will at some point, while creating child device, try to get a reference on uninitialized parent, resulting in the following warning: kobject: '(null)' ((ptrval)): is not initialized, yet kobject_get() is being called. The warning is observed after migrating a kernel 5.10.x to 6.1.x. Reverting commit 0d70af3c2530 ("fpga: bridge: Use standard dev_release for class driver") seems to remove the warning. This commit aggregates device_initialize() and device_add() into device_register() but this new call is done AFTER of_platform_populate Fixes: 0d70af3c2530 ("fpga: bridge: Use standard dev_release for class driver") Signed-off-by: Alexis Lothoré <alexis.lothore@xxxxxxxxxxx> Acked-by: Xu Yilun <yilun.xu@xxxxxxxxx> Link: https://lore.kernel.org/r/20230404133102.2837535-2-alexis.lothore@xxxxxxxxxxx Signed-off-by: Xu Yilun <yilun.xu@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/fpga/fpga-bridge.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/fpga/fpga-bridge.c +++ b/drivers/fpga/fpga-bridge.c @@ -360,7 +360,6 @@ fpga_bridge_register(struct device *pare bridge->dev.parent = parent; bridge->dev.of_node = parent->of_node; bridge->dev.id = id; - of_platform_populate(bridge->dev.of_node, NULL, NULL, &bridge->dev); ret = dev_set_name(&bridge->dev, "br%d", id); if (ret) @@ -372,6 +371,8 @@ fpga_bridge_register(struct device *pare return ERR_PTR(ret); } + of_platform_populate(bridge->dev.of_node, NULL, NULL, &bridge->dev); + return bridge; error_device: Patches currently in stable-queue which might be from alexis.lothore@xxxxxxxxxxx are queue-6.1/fpga-bridge-properly-initialize-bridge-device-before-populating-children.patch