Re: [PATCH] Uninline kcalloc()

From: Kyle Moffett
Date: Mon Sep 24 2007 - 09:01:21 EST

On Sep 24, 2007, at 01:35:08, Valdis.Kletnieks@xxxxxx wrote:
On Sun, 23 Sep 2007 00:03:49 +0400, Alexey Dobriyan said:
-static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
- if (n != 0 && size > ULONG_MAX / n)
- return NULL;
- return __kmalloc(n * size, flags | __GFP_ZERO);
+void *kcalloc(size_t n, size_t size, gfp_t flags);


This busticates some pretty subtle code in mm/slab.c that uses uses __builtin_return_address() for debugging - if you do this, then the "calling function" gets listed as "kcalloc()" rather than the much more useful "function that called kcalloc()" (which is what you care about).

(I remember going around and around multiple times getting those stupid inlines set up right, so that feature actually did something useful, otherwise kcalloc and kzalloc didn't report where they were called from).

Proper fix is to give __kmalloc a "void *caller" parameter and have all of the various wrapper functions pass in the value of __builtin_return_address() appropriately. I believe that even works properly for inline functions which may or may not be inlined.

Kyle Moffett

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