From f8062386671a596ca7022c61727a14a25679a0a1 Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Sat, 5 Dec 2015 16:13:53 -0800 Subject: [PATCH] of/fdt: Add mutex protection for calls to __unflatten_device_tree() __unflatten_device_tree() calls unflatten_dt_node(), which declares a static variable. It is therefore not reentrant. One of the callers of __unflatten_device_tree(), unflatten_device_tree(), is only called once during early initialization and does not need to be protected. The other caller, of_fdt_unflatten_tree(), can be called at any time, possibly multiple times in parallel. This can happen, for example, if multiple devicetree overlays have to be loaded and installed. Without this protection, errors such as the following may be seen. kernel: End of tree marker overwritten: e6a3a458 kernel: find_target_node: Failed to find target-indirect node at /fragment@0 kernel: __of_overlay_create: of_build_overlay_info() failed for tree@/ Add a mutex to of_fdt_unflatten_tree() to make the call reentrant. Cc: Pantelis Antoniou Signed-off-by: Guenter Roeck Cc: stable@vger.kernel.org # v4.1+ Signed-off-by: Rob Herring --- drivers/of/fdt.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c index 1bbe3a990ef1..655f79db7899 100644 --- a/drivers/of/fdt.c +++ b/drivers/of/fdt.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include #include @@ -436,6 +437,8 @@ static void *kernel_tree_alloc(u64 size, u64 align) return kzalloc(size, GFP_KERNEL); } +static DEFINE_MUTEX(of_fdt_unflatten_mutex); + /** * of_fdt_unflatten_tree - create tree of device_nodes from flat blob * @@ -447,7 +450,9 @@ static void *kernel_tree_alloc(u64 size, u64 align) void of_fdt_unflatten_tree(const unsigned long *blob, struct device_node **mynodes) { + mutex_lock(&of_fdt_unflatten_mutex); __unflatten_device_tree(blob, mynodes, &kernel_tree_alloc); + mutex_unlock(&of_fdt_unflatten_mutex); } EXPORT_SYMBOL_GPL(of_fdt_unflatten_tree); -- GitLab