diff mbox series

[v2,1/4] test-lib: ignore uninteresting LSan output

Message ID 7dd42212c0b0debe40504cca474f2a5d9207155a.1693263171.git.me@ttaylorr.com (mailing list archive)
State Accepted
Commit 370ef7e40df684f9b7314c8ca54892f4513eb903
Headers show
Series leak tests: mark remaining tests leak-free as such | expand

Commit Message

Taylor Blau Aug. 28, 2023, 10:52 p.m. UTC 
From: Jeff King <peff@peff.net>

When I run the tests in leak-checking mode the same way our CI job does,
like:

  make SANITIZE=leak \
       GIT_TEST_PASSING_SANITIZE_LEAK=true \
       GIT_TEST_SANITIZE_LEAK_LOG=true \
       test

then LSan can racily produce useless entries in the log files that look
like this:

  ==git==3034393==Unable to get registers from thread 3034307.

I think they're mostly harmless based on the source here:

  https://github.com/llvm/llvm-project/blob/7e0a52e8e9ef6394bb62e0b56e17fa23e7262411/compiler-rt/lib/lsan/lsan_common.cpp#L414

which reads:

    PtraceRegistersStatus have_registers =
        suspended_threads.GetRegistersAndSP(i, &registers, &sp);
    if (have_registers != REGISTERS_AVAILABLE) {
      Report("Unable to get registers from thread %llu.\n", os_id);
      // If unable to get SP, consider the entire stack to be reachable unless
      // GetRegistersAndSP failed with ESRCH.
      if (have_registers == REGISTERS_UNAVAILABLE_FATAL)
        continue;
      sp = stack_begin;
    }

The program itself still runs fine and LSan doesn't cause us to abort.
But test-lib.sh looks for any non-empty LSan logs and marks the test as
a failure anyway, under the assumption that we simply missed the failing
exit code somehow.

I don't think I've ever seen this happen in the CI job, but running
locally using clang-14 on an 8-core machine, I can't seem to make it
through a full run of the test suite without having at least one
failure. And it's a different one every time (though they do seem to
often be related to packing tests, which makes sense, since that is one
of our biggest users of threaded code).

We can hack around this by only counting LSan log files that contain a
line that doesn't match our known-uninteresting pattern.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
---
 t/test-lib.sh | 1 +
 1 file changed, 1 insertion(+)
diff mbox series

Patch

diff --git a/t/test-lib.sh b/t/test-lib.sh
index 293caf0f20..5ea5d1d62a 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -334,6 +334,7 @@  nr_san_dir_leaks_ () {
 	find "$TEST_RESULTS_SAN_DIR" \
 		-type f \
 		-name "$TEST_RESULTS_SAN_FILE_PFX.*" 2>/dev/null |
+	xargs grep -lv "Unable to get registers from thread" |
 	wc -l
 }