FAILED: patch "[PATCH] nvmem: core: fix use-after-free bugs in error paths" failed to apply to 5.15-stable tree

FAILED: patch "[PATCH] nvmem: core: fix use-after-free bugs in error paths" failed to apply to 5.15-stable tree

[gregkh]

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 5b6b6fc491899d583eaa75344e094796ae9b530b
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026061524-undefined-splinter-9744@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 5b6b6fc491899d583eaa75344e094796ae9b530b Mon Sep 17 00:00:00 2001
From: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Date: Sat, 30 May 2026 21:43:40 +0100
Subject: [PATCH] nvmem: core: fix use-after-free bugs in error paths

Fix several instances of error paths in which we call
__nvmem_device_put() - which may end up freeing the underlying memory
and other resources - and then keep on using the nvmem structure. Always
put the reference to the nvmem device as the last step before returning
the error code.

Cc: stable@vger.kernel.org
Fixes: 7ae6478b304b ("nvmem: core: rework nvmem cell instance creation")
Fixes: e888d445ac33 ("nvmem: resolve cells from DT at registration time")
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Signed-off-by: Srinivas Kandagatla <srini@kernel.org>
Link: https://patch.msgid.link/20260530204340.116743-3-srini@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 311cb2e5a5c0..e871181751f3 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -1468,18 +1468,16 @@ struct nvmem_cell *of_nvmem_cell_get(struct device_node *np, const char *id)
 	cell_entry = nvmem_find_cell_entry_by_node(nvmem, cell_np);
 	of_node_put(cell_np);
 	if (!cell_entry) {
-		__nvmem_device_put(nvmem);
 		nvmem_layout_module_put(nvmem);
-		if (nvmem->layout)
-			return ERR_PTR(-EPROBE_DEFER);
-		else
-			return ERR_PTR(-ENOENT);
+		ret = nvmem->layout ? -EPROBE_DEFER : -ENOENT;
+		__nvmem_device_put(nvmem);
+		return ERR_PTR(ret);
 	}
 
 	cell = nvmem_create_cell(cell_entry, id, cell_index);
 	if (IS_ERR(cell)) {
-		__nvmem_device_put(nvmem);
 		nvmem_layout_module_put(nvmem);
+		__nvmem_device_put(nvmem);
 	}
 
 	return cell;
@@ -1593,8 +1591,8 @@ void nvmem_cell_put(struct nvmem_cell *cell)
 		kfree_const(cell->id);
 
 	kfree(cell);
-	__nvmem_device_put(nvmem);
 	nvmem_layout_module_put(nvmem);
+	__nvmem_device_put(nvmem);
 }
 EXPORT_SYMBOL_GPL(nvmem_cell_put);