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Commit 8a9de9cde83d1c913bcbe5bd8c6291f5536a576c

Authored by Christoph Lameter
Committed by Greg Kroah-Hartman
1 parent c45247fdfb

slub: Do not hold slub_lock when calling sysfs_slab_add() 

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 <levinsasha928@gmail.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Showing 1 changed file with 2 additions and 1 deletions Side-by-side Diff

... ... @@ -3911,13 +3911,14 @@
3911 3911 if (kmem_cache_open(s, n,
3912 3912 size, align, flags, ctor)) {
3913 3913 list_add(&s->list, &slab_caches);
  3914 + up_write(&slub_lock);
3914 3915 if (sysfs_slab_add(s)) {
  3916 + down_write(&slub_lock);
3915 3917 list_del(&s->list);
3916 3918 kfree(n);
3917 3919 kfree(s);
3918 3920 goto err;
3919 3921 }
3920   - up_write(&slub_lock);
3921 3922 return s;
3922 3923 }
3923 3924 kfree(n);