On 2/18/22 14:13, Greg Kroah-Hartman 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.
Could we instead wrap it in some #ifdef that' only true for clang build?
That would make the workaround more precise and self-documented. Even
better if it can trigger using clang version range and once a fixed
clang version is here, it can be updated to stay true for older clangs.
> 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_)
>
