Re: [PATCH] sanitizer: [PR110027] Align asan_vec[0] to MAX (alignb, ASAN_RED_ZONE_SIZE)

[Hongtao Liu <crazylht@gmail.com>]

On Tue, Mar 12, 2024 at 8:00 PM liuhongt <hongtao.liu@intel.com> wrote:
>
> if alignb > ASAN_RED_ZONE_SIZE and offset[0] is not multiple of
> alignb. (base_align_bias - base_offset) may not aligned to alignb, and
> caused segement fault.
>
> Bootstrapped and regtested on x86_64-linux-gnu{-m32,}.
> Ok for trunk and backport to GCC13?
CC jakub, I see the code was added by
https://gcc.gnu.org/pipermail/gcc-patches/2018-December/512313.html
The issue in the PR is similar, but __m512 requires bigger
alignment(64 > ASAN_RED_ZONE_SIZE(32)), in that case we need to insert
MAX (alignb, ASAN_RED_ZONE_SIZE) instead of ASAN_RED_ZONE_SIZE.
Assume when alignb > ASAN_RED_ZONE_SIZE, it must be multiple of
ASAN_RED_ZONE_SIZE.
>
> gcc/ChangeLog:
>
>         PR sanitizer/110027
>         * cfgexpand.cc (expand_stack_vars): Align frame offset to
>         MAX (alignb, ASAN_RED_ZONE_SIZE).
>
> gcc/testsuite/ChangeLog:
>
>         * g++.dg/asan/pr110027.C: New test.
> ---
>  gcc/cfgexpand.cc                     |  2 +-
>  gcc/testsuite/g++.dg/asan/pr110027.C | 20 ++++++++++++++++++++
>  2 files changed, 21 insertions(+), 1 deletion(-)
>  create mode 100644 gcc/testsuite/g++.dg/asan/pr110027.C
>
> diff --git a/gcc/cfgexpand.cc b/gcc/cfgexpand.cc
> index 0de299c62e3..92062378d8e 100644
> --- a/gcc/cfgexpand.cc
> +++ b/gcc/cfgexpand.cc
> @@ -1214,7 +1214,7 @@ expand_stack_vars (bool (*pred) (size_t), class stack_vars_data *data)
>             {
>               if (data->asan_vec.is_empty ())
>                 {
> -                 align_frame_offset (ASAN_RED_ZONE_SIZE);
> +                 align_frame_offset (MAX (alignb, ASAN_RED_ZONE_SIZE));
>                   prev_offset = frame_offset.to_constant ();
>                 }
>               prev_offset = align_base (prev_offset,
> diff --git a/gcc/testsuite/g++.dg/asan/pr110027.C b/gcc/testsuite/g++.dg/asan/pr110027.C
> new file mode 100644
> index 00000000000..0067781bc89
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/asan/pr110027.C
> @@ -0,0 +1,20 @@
> +/* PR sanitizer/110027 */
> +/* { dg-do run } */
> +/* { dg-require-effective-target avx512f_runtime } */
> +/* { dg-options "-std=gnu++23 -mavx512f -fsanitize=address -O0 -g -fstack-protector-strong" } */
> +
> +#include <cstddef>
> +#include <cstdint>
> +
> +template <ptrdiff_t W, typename T>
> +using Vec [[gnu::vector_size(W * sizeof(T))]] = T;
> +
> +auto foo() {
> +  Vec<8, int64_t> ret{};
> +  return ret;
> +}
> +
> +int main() {
> +  foo();
> +  return 0;
> +}
> --
> 2.31.1
>


-- 
BR,
Hongtao