Re: Subject: Slab allocators: Remove kmem_cache_name() to fix invalid frees

[Christoph Lameter <clameter@sgi.com>]

A draft patch to allow anonymous caches follows. Allowing duplicate names
would also be possible. Just need to deal with sysfs. Maybe generate a
_x at the end?

Subject: slub: Support anonymous slabs

Slabs really do not need to have a name so one could pass NULL as a name. 
The name is only relevant for sysfs support. There we need a unique name.
Use the address of the kmem_cache structure as the name.

[Would output "" if debugging is one]


Signed-off-by: Christoph Lameter <clameter@sgi.com>

---
 mm/slub.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

Index: linux-2.6/mm/slub.c
===================================================================
--- linux-2.6.orig/mm/slub.c	2008-05-28 11:16:24.000000000 -0700
+++ linux-2.6/mm/slub.c	2008-05-28 11:17:33.000000000 -0700
@@ -4310,6 +4310,7 @@ static int sysfs_slab_add(struct kmem_ca
 	int err;
 	const char *name;
 	int unmergeable;
+	char buf[20];
 
 	if (slab_state < SYSFS)
 		/* Defer until later */
@@ -4322,8 +4323,13 @@ static int sysfs_slab_add(struct kmem_ca
 		 * This is typically the case for debug situations. In that
 		 * case we can catch duplicate names easily.
 		 */
-		sysfs_remove_link(&slab_kset->kobj, s->name);
+		if (s->name)
+			sysfs_remove_link(&slab_kset->kobj, s->name);
 		name = s->name;
+		if (!name) {
+			sprintf(buf, "%p", s);
+			name = buf;
+		}
 	} else {
 		/*
 		 * Create a unique name for the slab as a target
@@ -4343,7 +4349,7 @@ static int sysfs_slab_add(struct kmem_ca
 	if (err)
 		return err;
 	kobject_uevent(&s->kobj, KOBJ_ADD);
-	if (!unmergeable) {
+	if (!unmergeable && s->name) {
 		/* Setup first alias */
 		sysfs_slab_alias(s, s->name);
 		kfree(name);

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