kmemleak: Do not use off-slab management with SLAB_NOLEAKTRACE

With the slab allocator, if off-slab management is enabled for the
kmem_caches used by kmemleak, it leads to recursive calls into
kmemleak_alloc(). Off-slab management can be triggered by other config
options increasing the slab size, e.g. DEBUG_PAGEALLOC.

Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/mm/slab.c b/mm/slab.c
index 7dfa481..646db30 100644 (file)
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2261,9 +2261,11 @@ kmem_cache_create (const char *name, size_t size, size_t align,
        /*
         * Determine if the slab management is 'on' or 'off' slab.
         * (bootstrapping cannot cope with offslab caches so don't do
-        * it too early on.)
+        * it too early on. Always use on-slab management when
+        * SLAB_NOLEAKTRACE to avoid recursive calls into kmemleak)
         */
-       if ((size >= (PAGE_SIZE >> 3)) && !slab_early_init)
+       if ((size >= (PAGE_SIZE >> 3)) && !slab_early_init &&
+           !(flags & SLAB_NOLEAKTRACE))
                /*
                 * Size is large, assume best to place the slab management obj
                 * off-slab (should allow better packing of objs).