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of: fix memory leak related to safe_name() 

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
Tested-by: Mathieu Malaterre <mathieu.malaterre@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
This commit is contained in:
Frank Rowand 2016-06-16 10:51:46 -07:00 committed by Rob Herring
parent e1bcbee6f9
commit d9fc880723
3 changed files with 25 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
drivers/of/base.c
View File

@ -112,6 +112,7 @@ static ssize_t of_node_property_read(struct file *filp, struct kobject *kobj,
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 kobject *kobj, const char *orig_name)
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 device_node *np, struct property *pp)
int __of_attach_node_sysfs(struct device_node *np)
{
const char *name;
struct kobject *parent;
struct property *pp;
int rc;
@ -171,15 +176,16 @@ int __of_attach_node_sysfs(struct device_node *np)
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);
kfree(name);
if (rc)
return rc;
@ -1815,6 +1821,12 @@ int __of_remove_property(struct device_node *np, struct property *prop)
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 +1834,7 @@ void __of_remove_property_sysfs(struct device_node *np, struct property *prop)
/* 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 +1907,7 @@ void __of_update_property_sysfs(struct device_node *np, struct property *newprop
return;
if (oldprop)
sysfs_remove_bin_file(&np->kobj, &oldprop->attr);
__of_sysfs_remove_bin_file(np, oldprop);
__of_add_property_sysfs(np, newprop);
}

2
drivers/of/dynamic.c
View File

@ -55,7 +55,7 @@ void __of_detach_node_sysfs(struct device_node *np)
/* 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);
}

3
drivers/of/of_private.h
View File

@ -83,6 +83,9 @@ extern int __of_attach_node_sysfs(struct device_node *np);
extern void __of_detach_node(struct device_node *np);
extern void __of_detach_node_sysfs(struct device_node *np);
extern void __of_sysfs_remove_bin_file(struct device_node *np,
struct property *prop);
/* iterators for transactions, used for overlays */
/* forward iterator */
#define for_each_transaction_entry(_oft, _te) \