From: Aaron Tomlin <[email protected]>
Hi,
This patch is in response to BZ#42967 [1].
Using VM_BUG_ON so it's used only when CONFIG_DEBUG_VM is set,
given that ____cache_alloc_node() is a hot code path.
Cheers,
Aaron
[1]: https://bugzilla.kernel.org/show_bug.cgi?id=42967
---8<---
mm: slab: Verify the nodeid passed to ____cache_alloc_node
If the nodeid is > num_online_nodes() this can cause an
Oops and a panic(). The purpose of this patch is to assert
if this condition is true to aid debugging efforts rather
than some random NULL pointer dereference or page fault.
Signed-off-by: Aaron Tomlin <[email protected]>
Reviewed-by: Rik van Riel <[email protected]>
Acked-by: Christoph Lameter <[email protected]>
Acked-by: Rafael Aquini <[email protected]>
Acked-by: David Rientjes <[email protected]>
---
mm/slab.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/mm/slab.c b/mm/slab.c
index 856e4a1..09b4e20 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3412,6 +3412,7 @@ static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags,
void *obj;
int x;
+ VM_BUG_ON(nodeid > num_online_nodes());
l3 = cachep->nodelists[nodeid];
BUG_ON(!l3);
--
1.8.1.4