Messages in this thread Patch in this message | | | Date | Mon, 12 Aug 2013 13:00:26 +0200 | From | Wladislav Wiebe <> | Subject | [PATCH 1/1] of: fdt: fix memory initialization for expanded DT |
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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> --- drivers/of/fdt.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c index 6bb7cf2..b10ba00 100644 --- a/drivers/of/fdt.c +++ b/drivers/of/fdt.c @@ -392,6 +392,8 @@ static void __unflatten_device_tree(struct boot_param_header *blob, 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); -- 1.7.1
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