[PATCH] of: fix memory leak related to safe_name()
From: Frank Rowand <hidden>
Date: 2016-06-15 18:14:08
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
---
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)