From: Glauber Costa <glommer@parallels.com>
To: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>,
linux-mm@kvack.org, David Rientjes <rientjes@google.com>,
Joonsoo Kim <js1304@gmail.com>
Subject: Re: Common [02/19] slub: Use kmem_cache for the kmem_cache structure
Date: Fri, 3 Aug 2012 17:20:25 +0400 [thread overview]
Message-ID: <501BD019.70803@parallels.com> (raw)
In-Reply-To: <20120802201531.490489455@linux.com>
[-- Attachment #1: Type: text/plain, Size: 2135 bytes --]
On 08/03/2012 12:15 AM, Christoph Lameter wrote:
> Do not use kmalloc() but kmem_cache_alloc() for the allocation
> of the kmem_cache structures in slub.
>
> This is the way its supposed to be. Recent merges lost
> the freeing of the kmem_cache structure and so this is also
> fixing memory leak on kmem_cache_destroy() by adding
> the missing free action to sysfs_slab_remove().
Okay. the problems I am seeing are due to to this patch.
> Signed-off-by: Christoph Lameter <cl@linux.com>
>
> Index: linux-2.6/mm/slub.c
> ===================================================================
> --- linux-2.6.orig/mm/slub.c 2012-08-01 13:02:18.897656578 -0500
> +++ linux-2.6/mm/slub.c 2012-08-01 13:06:02.673597753 -0500
> @@ -213,7 +213,7 @@
> static inline void sysfs_slab_remove(struct kmem_cache *s)
> {
> kfree(s->name);
> - kfree(s);
> + kmem_cache_free(kmem_cache, s);
> }
>
> #endif
> @@ -3962,7 +3962,7 @@
> if (!n)
> return NULL;
>
> - s = kmalloc(kmem_size, GFP_KERNEL);
> + s = kmem_cache_alloc(kmem_cache, GFP_KERNEL);
> if (s) {
> if (kmem_cache_open(s, n,
> size, align, flags, ctor)) {
> @@ -3979,7 +3979,7 @@
> list_del(&s->list);
> kmem_cache_close(s);
> }
> - kfree(s);
> + kmem_cache_free(kmem_cache, s);
> }
> kfree(n);
> return NULL;
> @@ -5217,7 +5217,7 @@
> struct kmem_cache *s = to_slab(kobj);
>
> kfree(s->name);
> - kfree(s);
> + kmem_cache_free(kmem_cache, s);
> }
>
> static const struct sysfs_ops slab_sysfs_ops = {
> @@ -5342,6 +5342,8 @@
> kobject_uevent(&s->kobj, KOBJ_REMOVE);
> kobject_del(&s->kobj);
> kobject_put(&s->kobj);
> + kfree(s->name);
> + kmem_cache_free(kmem_cache, s);
> }
>
> /*
>
When a non-alias cache is freed, both sysfs_slab_remove and
kmem_cache_release are called.
You are freeing structures on both, so you have two double frees.
slab_sysfs_remove() is the correct place for it, so you need to remove
them from kmem_cache_release(), which becomes an empty function.
Please consider replacing your patch with the attached. Replacing your
patch by this one makes my test case work after the series is applied.
[-- Attachment #2: cl-updated.patch --]
[-- Type: text/x-patch, Size: 1577 bytes --]
Index: linux-slab/mm/slub.c
===================================================================
--- linux-slab.orig/mm/slub.c
+++ linux-slab/mm/slub.c
@@ -211,7 +211,7 @@ static inline int sysfs_slab_alias(struc
static inline void sysfs_slab_remove(struct kmem_cache *s)
{
kfree(s->name);
- kfree(s);
+ kmem_cache_free(kmem_cache, s);
}
#endif
@@ -3938,7 +3938,7 @@ struct kmem_cache *__kmem_cache_create(c
if (!n)
return NULL;
- s = kmalloc(kmem_size, GFP_KERNEL);
+ s = kmem_cache_alloc(kmem_cache, GFP_KERNEL);
if (s) {
if (kmem_cache_open(s, n,
size, align, flags, ctor)) {
@@ -3955,7 +3955,7 @@ struct kmem_cache *__kmem_cache_create(c
list_del(&s->list);
kmem_cache_close(s);
}
- kfree(s);
+ kmem_cache_free(kmem_cache, s);
}
kfree(n);
return NULL;
@@ -5188,14 +5188,6 @@ static ssize_t slab_attr_store(struct ko
return err;
}
-static void kmem_cache_release(struct kobject *kobj)
-{
- struct kmem_cache *s = to_slab(kobj);
-
- kfree(s->name);
- kfree(s);
-}
-
static const struct sysfs_ops slab_sysfs_ops = {
.show = slab_attr_show,
.store = slab_attr_store,
@@ -5203,7 +5195,6 @@ static const struct sysfs_ops slab_sysfs
static struct kobj_type slab_ktype = {
.sysfs_ops = &slab_sysfs_ops,
- .release = kmem_cache_release
};
static int uevent_filter(struct kset *kset, struct kobject *kobj)
@@ -5318,6 +5309,8 @@ static void sysfs_slab_remove(struct kme
kobject_uevent(&s->kobj, KOBJ_REMOVE);
kobject_del(&s->kobj);
kobject_put(&s->kobj);
+ kfree(s->name);
+ kmem_cache_free(kmem_cache, s);
}
/*
next prev parent reply other threads:[~2012-08-03 13:23 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-02 20:15 Common [00/19] Sl[auo]b: Common code rework V9 Christoph Lameter
2012-08-02 20:15 ` Common [01/19] slub: Add debugging to verify correct cache use on kmem_cache_free() Christoph Lameter
2012-08-02 20:37 ` David Rientjes
2012-08-02 20:42 ` Christoph Lameter
2012-08-02 20:47 ` David Rientjes
2012-08-03 13:45 ` Christoph Lameter
2012-08-02 20:15 ` Common [02/19] slub: Use kmem_cache for the kmem_cache structure Christoph Lameter
2012-08-02 20:52 ` David Rientjes
2012-08-03 14:07 ` Christoph Lameter
2012-08-03 13:20 ` Glauber Costa [this message]
2012-08-03 13:52 ` Christoph Lameter
2012-08-03 13:53 ` Glauber Costa
2012-08-03 14:02 ` Christoph Lameter
2012-08-02 20:15 ` Common [03/19] Rename oops label Christoph Lameter
2012-08-02 20:45 ` David Rientjes
2012-08-02 20:15 ` Common [04/19] Improve error handling in kmem_cache_create Christoph Lameter
2012-08-02 20:58 ` David Rientjes
2012-08-02 20:15 ` Common [05/19] Move list_add() to slab_common.c Christoph Lameter
2012-08-02 21:18 ` David Rientjes
2012-08-02 20:15 ` Common [06/19] Extract a common function for kmem_cache_destroy Christoph Lameter
2012-08-02 20:15 ` Common [07/19] Always use the name "kmem_cache" for the slab cache with the kmem_cache structure Christoph Lameter
2012-08-02 20:15 ` Common [08/19] Move freeing of kmem_cache structure to common code Christoph Lameter
2012-08-02 20:15 ` Common [09/19] Get rid of __kmem_cache_destroy Christoph Lameter
2012-08-02 20:15 ` Common [10/19] Move duping of slab name to slab_common.c Christoph Lameter
2012-08-02 20:15 ` Common [11/19] Do slab aliasing call from common code Christoph Lameter
2012-08-02 20:15 ` Common [12/19] Move sysfs_slab_add to common Christoph Lameter
2012-08-02 20:15 ` Common [13/19] slub: Use a statically allocated kmem_cache boot structure for bootstrap Christoph Lameter
2012-08-02 20:15 ` Common [14/19] slub: Introduce function for opening boot caches Christoph Lameter
2012-08-02 20:15 ` Common [15/19] create common create_kmalloc_cache() Christoph Lameter
2012-08-02 20:15 ` Common [16/19] Move kmem_cache allocations into common code Christoph Lameter
2012-08-02 20:15 ` Common [17/19] Shrink __kmem_cache_create() parameter lists Christoph Lameter
2012-08-02 20:15 ` Common [18/19] Move kmem_cache refcounting to common code Christoph Lameter
2012-08-02 20:15 ` Common [19/19] Common alignment code Christoph Lameter
2012-08-03 13:09 ` Common [00/19] Sl[auo]b: Common code rework V9 Glauber Costa
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