On Tue, Mar 12, 2024 at 07:57:59PM +0800, liuhongt 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? > > 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,
This doesn't look correct to me. The above is done just once for the first var partition. And var partitions are sorted by stack_var_cmp, which puts > MAX_SUPPORTED_STACK_ALIGNMENT alignment vars first (that should be none on x86, the above is quite huge alignment), then on size decreasing and only after that on alignment decreasing. So, try to add some other variable with larger size and smaller alignment to the frame (and make sure it isn't optimized away). alignb above is the alignment of the first partition's var, if align_frame_offset really needs to depend on the var alignment, it probably should be the maximum alignment of all the vars with alignment alignb * BITS_PER_UNIT <= MAX_SUPPORTED_STACK_ALIGNMENT > 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 Jakub