Ok, I found https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110027 : "[11/12 regression] Stack objects with extended alignments (vectors etc) misaligned on detect_stack_use_after_return".
As described in that bug, turning _off_ the ASAN_OPTION detect_stack_use_after_return makes the misalignment go away: $ ~/ins/gcc-13-103-gf732bf6a603/bin/gcc -fsanitize=address -fstack- protector asan-align.c -o asan-align $ LD_LIBRARY_PATH=/home/ubuntu/ins/gcc-13-103-gf732bf6a603/lib64 ./asan-align explicitly aligned variable: 0x7f6c6f100020 asan-align: asan-align.c:11: main: Assertion `addr % 64 == 0' failed. Aborted $ LD_LIBRARY_PATH=/home/ubuntu/ins/gcc-13-103-gf732bf6a603/lib64 ASAN_OPTIONS="detect_stack_use_after_return=false" ./asan-align explicitly aligned variable: 0x7ffe189ec4c0 The fix for master (14.x) is in https://gcc.gnu.org/git/gitweb.cgi?p=gcc.git;h=467898d513e602f5b5fc4183052217d7e6d6e8ab, while it was merged to 13.x in https://gcc.gnu.org/git/gitweb.cgi?p=gcc.git;h=a16d90ec302e588dab5d7d31ccdd7b3fd5c6214e . I think it should be relatively safe to apply this patch to Ubuntu's gcc packages? ** Bug watch added: GCC Bugzilla #110027 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110027 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2023424 Title: GCC 13 on Lunar exhibits AddressSanitizer/UndefinedBehaviorSanitizer bug that doesn't manifest elsewhere To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gcc-13/+bug/2023424/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
