I noticed that my initial attempt was invalid. The one below appears to be
correct, although I am not sure whether there is a better implementation.
this patch also fixes a kfree(skb) in net/core/dev.c, what do you think?
Roel
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
---
include/linux/kernel.h | 4 ++++
include/linux/slab.h | 3 +++
mm/slab.c | 2 ++
mm/slob.c | 2 ++
mm/slub.c | 2 ++
net/core/dev.c | 2 +-
6 files changed, 14 insertions(+), 1 deletions(-)
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 7fa3718..b7f22d8 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -526,6 +526,10 @@ struct sysinfo {
aren't permitted). */
#define BUILD_BUG_ON_ZERO(e) (sizeof(char[1 - 2 * !!(e)]) - 1)
+/* If the type of x is TYPE, force a compilation error, otherwise produce x */
+#define BUILD_BUG_ON_TYPE(x, TYPE) __builtin_choose_expr( \
+ __builtin_types_compatible_p(typeof(x), TYPE), (void)0, (x))
+
/* Trap pasters of __FUNCTION__ at compile-time */
#define __FUNCTION__ (__func__)
diff --git a/include/linux/slab.h b/include/linux/slab.h
index 24c5602..30c28f9 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -130,6 +130,9 @@ void kfree(const void *);
void kzfree(const void *);
size_t ksize(const void *);
+/* This ensures that kfree is not called with a struct sk_buff* */
+#define kfree(x) kfree(BUILD_BUG_ON_TYPE(x, struct sk_buff*))
+
/*
* Allocator specific definitions. These are mainly used to establish optimized
* ways to convert kmalloc() calls to kmem_cache_alloc() invocations by
diff --git a/mm/slab.c b/mm/slab.c
index 4d00855..cbcd28a 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3711,6 +3711,7 @@ EXPORT_SYMBOL(kmem_cache_free);
* Don't free memory not originally allocated by kmalloc()
* or you will run into trouble.
*/
+#undef kfree
void kfree(const void *objp)
{
struct kmem_cache *c;
@@ -3727,6 ...
