* [PATCH] of: fix memory leak related to safe_name()
@ 2016-06-15 18:13 Frank Rowand
2016-06-15 19:12 ` Rob Herring
0 siblings, 1 reply; 3+ messages in thread
From: Frank Rowand @ 2016-06-15 18:13 UTC (permalink / raw)
To: Mathieu Malaterre, Rob Herring; +Cc: devicetree, linuxppc-dev, linux-kernel
From: Frank Rowand <frank.rowand@am.sony.com>
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 <frank.rowand@am.sony.com>
Reported-by: mathieu.malaterre@gmail.com
---
drivers/of/base.c | 29 ++++++++++++++++++++---------
drivers/of/dynamic.c | 2 +-
include/linux/of.h | 2 ++
3 files changed, 23 insertions(+), 10 deletions(-)
Index: b/drivers/of/base.c
===================================================================
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -112,6 +112,7 @@ static ssize_t of_node_property_read(str
return memory_read_from_buffer(buf, count, &offset, pp->value, pp->length);
}
+/* always return newly allocated name, caller must free after use */
static const char *safe_name(struct kobject *kobj, const char *orig_name)
{
const char *name = orig_name;
@@ -126,9 +127,12 @@ static const char *safe_name(struct kobj
name = kasprintf(GFP_KERNEL, "%s#%i", orig_name, ++i);
}
- if (name != orig_name)
+ if (name == orig_name) {
+ name = kstrdup(orig_name, GFP_KERNEL);
+ } else {
pr_warn("device-tree: Duplicate name in %s, renamed to \"%s\"\n",
kobject_name(kobj), name);
+ }
return name;
}
@@ -159,6 +163,7 @@ int __of_add_property_sysfs(struct devic
int __of_attach_node_sysfs(struct device_node *np)
{
const char *name;
+ struct kobject *parent;
struct property *pp;
int rc;
@@ -171,15 +176,15 @@ int __of_attach_node_sysfs(struct device
np->kobj.kset = of_kset;
if (!np->parent) {
/* Nodes without parents are new top level trees */
- rc = kobject_add(&np->kobj, NULL, "%s",
- safe_name(&of_kset->kobj, "base"));
+ name = safe_name(&of_kset->kobj, "base");
+ parent = NULL;
} else {
name = safe_name(&np->parent->kobj, kbasename(np->full_name));
- if (!name || !name[0])
- return -EINVAL;
-
- rc = kobject_add(&np->kobj, &np->parent->kobj, "%s", name);
+ parent = &np->parent->kobj;
}
+ if (!name)
+ return -ENOMEM;
+ rc = kobject_add(&np->kobj, parent, "%s", name);
if (rc)
return rc;
@@ -1815,6 +1820,12 @@ int __of_remove_property(struct device_n
return 0;
}
+void __of_sysfs_remove_bin_file(struct device_node *np, struct property *prop)
+{
+ sysfs_remove_bin_file(&np->kobj, &prop->attr);
+ kfree(prop->attr.attr.name);
+}
+
void __of_remove_property_sysfs(struct device_node *np, struct property *prop)
{
if (!IS_ENABLED(CONFIG_SYSFS))
@@ -1822,7 +1833,7 @@ void __of_remove_property_sysfs(struct d
/* at early boot, bail here and defer setup to of_init() */
if (of_kset && of_node_is_attached(np))
- sysfs_remove_bin_file(&np->kobj, &prop->attr);
+ __of_sysfs_remove_bin_file(np, prop);
}
/**
@@ -1895,7 +1906,7 @@ void __of_update_property_sysfs(struct d
return;
if (oldprop)
- sysfs_remove_bin_file(&np->kobj, &oldprop->attr);
+ __of_sysfs_remove_bin_file(np, oldprop);
__of_add_property_sysfs(np, newprop);
}
Index: b/drivers/of/dynamic.c
===================================================================
--- a/drivers/of/dynamic.c
+++ b/drivers/of/dynamic.c
@@ -55,7 +55,7 @@ void __of_detach_node_sysfs(struct devic
/* only remove properties if on sysfs */
if (of_node_is_attached(np)) {
for_each_property_of_node(np, pp)
- sysfs_remove_bin_file(&np->kobj, &pp->attr);
+ __of_sysfs_remove_bin_file(np, pp);
kobject_del(&np->kobj);
}
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);
#else /* CONFIG_OF_DYNAMIC */
/* Dummy ref counting routines - to be implemented later */
static inline struct device_node *of_node_get(struct device_node *node)
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] of: fix memory leak related to safe_name()
2016-06-15 18:13 [PATCH] of: fix memory leak related to safe_name() Frank Rowand
@ 2016-06-15 19:12 ` Rob Herring
2016-06-15 20:34 ` Frank Rowand
0 siblings, 1 reply; 3+ messages in thread
From: Rob Herring @ 2016-06-15 19:12 UTC (permalink / raw)
To: Frank Rowand; +Cc: Mathieu Malaterre, devicetree, linuxppc-dev, linux-kernel
On Wed, Jun 15, 2016 at 1:13 PM, Frank Rowand <frowand.list@gmail.com> wrote:
> From: Frank Rowand <frank.rowand@am.sony.com>
>
> 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 <frank.rowand@am.sony.com>
> Reported-by: mathieu.malaterre@gmail.com
[...]
> 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?
> #else /* CONFIG_OF_DYNAMIC */
> /* Dummy ref counting routines - to be implemented later */
> static inline struct device_node *of_node_get(struct device_node *node)
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] of: fix memory leak related to safe_name()
2016-06-15 19:12 ` Rob Herring
@ 2016-06-15 20:34 ` Frank Rowand
0 siblings, 0 replies; 3+ messages in thread
From: Frank Rowand @ 2016-06-15 20:34 UTC (permalink / raw)
To: Rob Herring; +Cc: Mathieu Malaterre, devicetree, linuxppc-dev, linux-kernel
On 06/15/16 12:12, Rob Herring wrote:
> On Wed, Jun 15, 2016 at 1:13 PM, Frank Rowand <frowand.list@gmail.com> wrote:
>> From: Frank Rowand <frank.rowand@am.sony.com>
>>
>> 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 <frank.rowand@am.sony.com>
>> Reported-by: mathieu.malaterre@gmail.com
>
> [...]
>
>> 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
>
>> #else /* CONFIG_OF_DYNAMIC */
>> /* Dummy ref counting routines - to be implemented later */
>> static inline struct device_node *of_node_get(struct device_node *node)
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2016-06-15 19:12 ` Rob Herring
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