This is a note to let you know that I've just added the patch titled
of: fdt: fix memory initialization for expanded DT
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
of-fdt-fix-memory-initialization-for-expanded-dt.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 9e40127526e857fa3f29d51e83277204fbdfc6ba Mon Sep 17 00:00:00 2001
From: Wladislav Wiebe <wladislav.kw@xxxxxxxxx>
Date: Mon, 12 Aug 2013 13:06:53 +0200
Subject: of: fdt: fix memory initialization for expanded DT
From: Wladislav Wiebe <wladislav.kw@xxxxxxxxx>
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@xxxxxxxxx>
Acked-by: Alexander Sverdlin <alexander.sverdlin@xxxxxxx>
Signed-off-by: Rob Herring <rob.herring@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/of/fdt.c | 2 ++
1 file changed, 2 insertions(+)
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -390,6 +390,8 @@ 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);
Patches currently in stable-queue which might be from wladislav.kw@xxxxxxxxx are
queue-3.4/of-fdt-fix-memory-initialization-for-expanded-dt.patch
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