This is a note to let you know that I've just added the patch titled
slub: Do not hold slub_lock when calling sysfs_slab_add()
to the 3.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
slub-do-not-hold-slub_lock-when-calling-sysfs_slab_add.patch
and it can be found in the queue-3.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 66c4c35c6bc5a1a452b024cf0364635b28fd94e4 Mon Sep 17 00:00:00 2001
From: Christoph Lameter <[email protected]>
Date: Tue, 17 Jan 2012 09:27:31 -0600
Subject: slub: Do not hold slub_lock when calling sysfs_slab_add()
From: Christoph Lameter <[email protected]>
commit 66c4c35c6bc5a1a452b024cf0364635b28fd94e4 upstream.
sysfs_slab_add() calls various sysfs functions that actually may
end up in userspace doing all sorts of things.
Release the slub_lock after adding the kmem_cache structure to the list.
At that point the address of the kmem_cache is not known so we are
guaranteed exlusive access to the following modifications to the
kmem_cache structure.
If the sysfs_slab_add fails then reacquire the slub_lock to
remove the kmem_cache structure from the list.
Reported-by: Sasha Levin <[email protected]>
Acked-by: Eric Dumazet <[email protected]>
Signed-off-by: Christoph Lameter <[email protected]>
Signed-off-by: Pekka Enberg <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
mm/slub.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3911,13 +3911,14 @@ struct kmem_cache *kmem_cache_create(con
if (kmem_cache_open(s, n,
size, align, flags, ctor)) {
list_add(&s->list, &slab_caches);
+ up_write(&slub_lock);
if (sysfs_slab_add(s)) {
+ down_write(&slub_lock);
list_del(&s->list);
kfree(n);
kfree(s);
goto err;
}
- up_write(&slub_lock);
return s;
}
kfree(n);
Patches currently in stable-queue which might be from [email protected] are
queue-3.2/slub-do-not-hold-slub_lock-when-calling-sysfs_slab_add.patch
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