Re: [PATCH] of: fix memory leak related to safe_name()

On 06/15/16 12:12, Rob Herring wrote:

On Wed, Jun 15, 2016 at 1:13 PM, Frank Rowand [off-list ref] wrote:

quoted

From: Frank Rowand <redacted>

Fix a memory leak resulting from memory allocation in safe_name().
This patch fixes all call sites of safe_name().

Mathieu Malaterre reported the memory leak on boot:

On my PowerMac device-tree would generate a duplicate name:

[    0.023043] device-tree: Duplicate name in PowerPC,G4@0, renamed to "l2-cache#1"

in this case a newly allocated name is generated by `safe_name`. However
in this case it is never deallocated.

The bug was found using kmemleak reported as:

unreferenced object 0xdf532e60 (size 32):
  comm "swapper", pid 1, jiffies 4294892300 (age 1993.532s)
  hex dump (first 32 bytes):
    6c 32 2d 63 61 63 68 65 23 31 00 dd e4 dd 1e c2  l2-cache#1......
    ec d4 ba ce 04 ec cc de 8e 85 e9 ca c4 ec cc 9e  ................
  backtrace:
    [<c02d3350>] kvasprintf+0x64/0xc8
    [<c02d3400>] kasprintf+0x4c/0x5c
    [<c0453814>] safe_name.isra.1+0x80/0xc4
    [<c04545d8>] __of_attach_node_sysfs+0x6c/0x11c
    [<c075f21c>] of_core_init+0x8c/0xf8
    [<c0729594>] kernel_init_freeable+0xd4/0x208
    [<c00047e8>] kernel_init+0x24/0x11c
    [<c00158ec>] ret_from_kernel_thread+0x5c/0x64

Link: https://bugzilla.kernel.org/show_bug.cgi?id=120331

Signed-off-by: Frank Rowand <redacted>
Reported-by: mathieu.malaterre@gmail.com

[...]

quoted

Index: b/include/linux/of.h
===================================================================

--- a/include/linux/of.h
+++ b/include/linux/of.h

@@ -121,6 +121,8 @@ static inline int of_node_is_attached(st
 #ifdef CONFIG_OF_DYNAMIC
 extern struct device_node *of_node_get(struct device_node *node);
 extern void of_node_put(struct device_node *node);
+extern void __of_sysfs_remove_bin_file(struct device_node *np,
+                                      struct property *prop);

Should be internal to DT code, right?Yes.

Yes, thanks.  v2 on the way, moved prototype to of_private.h

quoted

 #else /* CONFIG_OF_DYNAMIC */
 /* Dummy ref counting routines - to be implemented later */
 static inline struct device_node *of_node_get(struct device_node *node)