FEX-Emu/linux
1
0
Fork 0
mirror of https://github.com/FEX-Emu/linux.git synced 2024-12-26 11:28:28 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

of/fdt: Add mutex protection for calls to __unflatten_device_tree()

Browse Source 
__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 <pantelis.antoniou@konsulko.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Cc: stable@vger.kernel.org # v4.1+
Signed-off-by: Rob Herring <robh@kernel.org>
This commit is contained in:
Guenter Roeck 2015-12-05 16:13:53 -08:00 committed by Rob Herring
parent ba85edbe0d
commit f806238667
1 changed files with 5 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
drivers/of/fdt.c
View File

@ -13,6 +13,7 @@
#include <linux/kernel.h>
#include <linux/initrd.h>
#include <linux/memblock.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/of_fdt.h>
#include <linux/of_reserved_mem.h>
@ -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);