https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112812
Bug ID: 112812
Summary: Regression: ASAN + stack-protector breaks alignment of
stack variables
Product: gcc
Version: 13.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: tonyb at cybernetics dot com
Target Milestone: ---
Created attachment 56755
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56755&action=edit
Test case
The combination of -fsanitize=address and -fstack-protector-strong causes gcc
13 to misalign stack variables. Attached is a test program that requests
64-byte alignment of a stack variable. With -fsanitize=address and
-fstack-protector-strong, the address is aligned on a 32-byte boundary but not
a 64-byte boundary. With other combinations of options the alignment is
correct. Running on x86_64.
Compile options:
gcc -m64 -Wall -O2 -U_FORTIFY_SOURCE -fstack-protector-strong
-fsanitize=address -fno-omit-frame-pointer
Test fails with gcc version 13.2.1 20231201
Configured with: ../gcc/configure --host=x86_64-pc-linux-gnu
--enable-languages=c
I believe gcc 12 did not have this bug. I noticed the problem when UBSan
complained about a misaligned pointer which led back to a stack variable after
upgrading from gcc 12.3 to gcc 13.2.
