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Commit d9fc8807 authored by Frank Rowand's avatar Frank Rowand Committed by Rob Herring
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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: default avatarFrank Rowand <frank.rowand@am.sony.com>
Reported-by: default avatar <mathieu.malaterre@gmail.com>
Tested-by: default avatarMathieu Malaterre <mathieu.malaterre@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarRob Herring <robh@kernel.org>
parent e1bcbee6

drivers/of/base.c

+21 −9
Original line number Diff line number Diff line
@@ -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);

}

drivers/of/dynamic.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

	}

drivers/of/of_private.h

+3 −0
Original line number Diff line number Diff line
@@ -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) \