[NekoAsakura]

• Issue: perf trampoline segfaults on UBSan builds #161288

[vstinner]

LGTM.

I tested building Python with ./configure --with-undefined-behavior-sanitizer CC=clang LD=clang && make clean && make.

Without the fix, ./python -X perf -c pass logs a huge UBSan error and exit the process.

With the fix, ./python -X perf -c pass and ./python -X perf_jit -c pass complete successfully.

I confirm that #if __has_feature(undefined_behavior_sanitizer) test is true in C code built with clang -fsanitize=function or -fsanitize=undefined.

cc @pablogsal @StanFromIreland

[StanFromIreland]

test_samply_profiler has the same skip:

cpython/Lib/test/test_samply_profiler.py

Lines 17 to 20 in 0d3ab6f

	if support.check_sanitizer(address=True, memory=True, ub=True, function=True):
	# gh-109580: Skip the test because it does crash randomly if Python is
	# built with ASAN.
	raise unittest.SkipTest("test crash randomly on ASAN/MSAN/UBSAN build")

It can probably be removed as well (I haven't checked)?

[NekoAsakura]

@StanFromIreland Good catch, dropped it too.

[miss-islington-app]

Thanks @NekoAsakura for the PR, and @vstinner for merging it 🌮🎉.. I'm working now to backport this PR to: 3.14, 3.15.
🐍🍒⛏🤖

[miss-islington-app]

Sorry, @NekoAsakura and @vstinner, I could not cleanly backport this to 3.14 due to a conflict.

Please backport manually with cherry_picker, see the devguide for more information.

cherry_picker a14cccbaa4787860ede0945ffaf67cf14b34c8e2 3.14

[bedevere-app]

GH-161348 is a backport of this pull request to the 3.15 branch.

[bedevere-app]

GH-161350 is a backport of this pull request to the 3.14 branch.