Re: [PATCH] slab: fix caller tracking on !CONFIG_DEBUG_SLAB && CONFIG_TRACING

[David Rientjes <rientjes@google.com>]

On Thu, 8 Apr 2010, Xiaotian Feng wrote:

> diff --git a/include/linux/slab.h b/include/linux/slab.h
> index 4884462..1a0625c 100644
> --- a/include/linux/slab.h
> +++ b/include/linux/slab.h
> @@ -267,7 +267,7 @@ static inline void *kmem_cache_alloc_node(struct kmem_cache *cachep,
>   * allocator where we care about the real place the memory allocation
>   * request comes from.
>   */
> -#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB)
> +#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB) || defined(CONFIG_TRACING)
>  extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
>  #define kmalloc_track_caller(size, flags) \
>  	__kmalloc_track_caller(size, flags, _RET_IP_)
> @@ -285,7 +285,7 @@ extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
>   * standard allocator where we care about the real place the memory
>   * allocation request comes from.
>   */
> -#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB)
> +#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB) || defined(CONFIG_TRACING)
>  extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
>  #define kmalloc_node_track_caller(size, flags, node) \
>  	__kmalloc_node_track_caller(size, flags, node, \

This doesn't work if the underlying slab allocator doesn't define 
__kmalloc_node_track_caller() regardless of whether CONFIG_TRACING is 
enabled or not.  SLOB, for example, never defines it, and that's why the 
conditional exists in the way it currently does.

This is your patch with CONFIG_EMBEDDED && CONFIG_SLOB:

mm/built-in.o: In function `__krealloc':
(.text+0x1283c): undefined reference to `__kmalloc_track_caller'
mm/built-in.o: In function `kmemdup':
(.text+0x128b4): undefined reference to `__kmalloc_track_caller'
mm/built-in.o: In function `kstrndup':
(.text+0x128fc): undefined reference to `__kmalloc_track_caller'
mm/built-in.o: In function `kstrdup':
(.text+0x12943): undefined reference to `__kmalloc_track_caller'
mm/built-in.o: In function `memdup_user':
(.text+0x129f7): undefined reference to `__kmalloc_track_caller'
drivers/built-in.o:(.text+0xc48a4): more undefined references to `__kmalloc_track_caller' follow
net/built-in.o: In function `__alloc_skb':
(.text+0x8dc6): undefined reference to `__kmalloc_node_track_caller'

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