Messages in this thread Patch in this message |  | | Subject | slob: Check for NULL pointer before calling ctor() | From | Steven Rostedt <> | Date | Thu, 17 Jan 2013 12:13:46 -0500 |
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[ Sorry for the duplicate email, it's linux-mm@kvack.org not linux-mm@vger.kernel.org ]
While doing some code inspection, I noticed that the slob constructor method can be called with a NULL pointer. If memory is tight and slob fails to allocate with slob_alloc() or slob_new_pages() it still calls the ctor() method with a NULL pointer. Looking at the first ctor() method I found, I noticed that it can not handle a NULL pointer (I'm sure others probably can't either):
static void sighand_ctor(void *data) { struct sighand_struct *sighand = data;
spin_lock_init(&sighand->siglock); init_waitqueue_head(&sighand->signalfd_wqh); }
The solution is to only call the ctor() method if allocation succeeded.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/mm/slob.c b/mm/slob.c index a99fdf7..48fcb90 100644 --- a/mm/slob.c +++ b/mm/slob.c @@ -554,7 +554,7 @@ void *kmem_cache_alloc_node(struct kmem_cache *c, gfp_t flags, int node) flags, node); } - if (c->ctor) + if (b && c->ctor) c->ctor(b); kmemleak_alloc_recursive(b, c->size, 1, c->flags, flags);
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