Re: [PATCH] slab: remove __alloc_size attribute from __kmalloc_track_caller

[Nick Desaulniers]

On Fri, Feb 18, 2022 at 5:14 AM Greg Kroah-Hartman
<gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>
> Commit c37495d6254c ("slab: add __alloc_size attributes for better
> bounds checking") added __alloc_size attributes to a bunch of kmalloc
> function prototypes.  Unfortunately the change to __kmalloc_track_caller
> seems to cause clang to generate broken code and the first time this is
> called when booting, the box will crash.
>
> While the compiler problems are being reworked and attempted to be
> solved, let's just drop the attribute to solve the issue now.  Once it
> is resolved it can be added back.

Sorry about the mess; we'll get it cleaned up!
Acked-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Link: https://github.com/ClangBuiltLinux/linux/issues/1599

>
> Fixes: c37495d6254c ("slab: add __alloc_size attributes for better bounds checking")
> Cc: stable <stable@xxxxxxxxxxxxxxx>
> Cc: Kees Cook <keescook@xxxxxxxxxxxx>
> Cc: Daniel Micay <danielmicay@xxxxxxxxx>
> Cc: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
> Cc: Christoph Lameter <cl@xxxxxxxxx>
> Cc: Pekka Enberg <penberg@xxxxxxxxxx>
> Cc: David Rientjes <rientjes@xxxxxxxxxx>
> Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Vlastimil Babka <vbabka@xxxxxxx>
> Cc: Nathan Chancellor <nathan@xxxxxxxxxx>
> Cc: linux-mm@xxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Cc: llvm@xxxxxxxxxxxxxxx
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> ---
>  include/linux/slab.h | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/include/linux/slab.h b/include/linux/slab.h
> index 37bde99b74af..5b6193fd8bd9 100644
> --- a/include/linux/slab.h
> +++ b/include/linux/slab.h
> @@ -660,8 +660,7 @@ static inline __alloc_size(1, 2) void *kcalloc(size_t n, size_t size, gfp_t flag
>   * allocator where we care about the real place the memory allocation
>   * request comes from.
>   */
> -extern void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller)
> -                                  __alloc_size(1);
> +extern void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller);
>  #define kmalloc_track_caller(size, flags) \
>         __kmalloc_track_caller(size, flags, _RET_IP_)
>
> --
> 2.35.1
>


-- 
Thanks,
~Nick Desaulniers