| From | Ben Hutchings <> | Date | Sun, 08 Sep 2013 03:52:01 +0100 | Subject | [084/121] of: fdt: fix memory initialization for expanded DT |
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3.2.51-rc1 review patch. If anyone has any objections, please let me know.
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From: Wladislav Wiebe <wladislav.kw@gmail.com>
commit 9e40127526e857fa3f29d51e83277204fbdfc6ba upstream.
Already existing property flags are filled wrong for properties created from initial FDT. This could cause problems if this DYNAMIC device-tree functions are used later, i.e. properties are attached/detached/replaced. Simply dumping flags from the running system show, that some initial static (not allocated via kzmalloc()) nodes are marked as dynamic.
I putted some debug extensions to property_proc_show(..) : .. + if (OF_IS_DYNAMIC(pp)) + pr_err("DEBUG: xxx : OF_IS_DYNAMIC\n"); + if (OF_IS_DETACHED(pp)) + pr_err("DEBUG: xxx : OF_IS_DETACHED\n");
when you operate on the nodes (e.g.: ~$ cat /proc/device-tree/*some_node*) you will see that those flags are filled wrong, basically in most cases it will dump a DYNAMIC or DETACHED status, which is in not true. (BTW. this OF_IS_DETACHED is a own define for debug purposes which which just make a test_bit(OF_DETACHED, &x->_flags)
If nodes are dynamic kernel is allowed to kfree() them. But it will crash attempting to do so on the nodes from FDT -- they are not allocated via kzmalloc().
Signed-off-by: Wladislav Wiebe <wladislav.kw@gmail.com> Acked-by: Alexander Sverdlin <alexander.sverdlin@nsn.com> Signed-off-by: Rob Herring <rob.herring@calxeda.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- drivers/of/fdt.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/drivers/of/fdt.c +++ b/drivers/of/fdt.c @@ -389,6 +389,8 @@ static void __unflatten_device_tree(stru mem = (unsigned long) dt_alloc(size + 4, __alignof__(struct device_node)); + memset((void *)mem, 0, size); + ((__be32 *)mem)[size / 4] = cpu_to_be32(0xdeadbeef); pr_debug(" unflattening %lx...\n", mem);
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