Re: [PATCH v3 0/8] add a test mode for SANITIZE=leak, run it in CI

[Jeff King <peff@peff.net>]

On Wed, Sep 01, 2021 at 05:56:31AM -0400, Jeff King wrote:

> +else
> +	# The test script has possible LSAN failures. Just disable
> +	# leak-checking entirely. Another option would be to log the failures
> +	# with:
> +	#
> +	#   LSAN_OPTIONS=exitcode=0:log_path=$TEST_DIRECTORY/lsan/out
> +	#
> +	# The results are rather confusing, though, as the logs are
> +	# per-process; you have no idea which one came from which test script.
> +	# Ideally we'd send them to descriptor 4 along with the rest of the
> +	# script log, but there's no LSAN_OPTION for that (recent versions of
> +	# libsanitizer do have a public function to do so, so we could hook it
> +	# ourselves via common-main).
> +	LSAN_OPTIONS=detect_leaks=0
> +fi

I was curious about the fd thing. The patch below implements it, and
lets t0203 (for example) pass while including its sanitizer output in a
--verbose-log.

But this is exactly the kind of gross complexity I was suggesting to
avoid. :)

diff --git a/Makefile b/Makefile
index d1feab008f..ba2174fb79 100644
--- a/Makefile
+++ b/Makefile
@@ -1260,6 +1260,7 @@ ifdef SANITIZE
 SANITIZERS := $(foreach flag,$(subst $(comma),$(space),$(SANITIZE)),$(flag))
 BASIC_CFLAGS += -fsanitize=$(SANITIZE) -fno-sanitize-recover=$(SANITIZE)
 BASIC_CFLAGS += -fno-omit-frame-pointer
+BASIC_CFLAGS += -DENABLE_CUSTOM_SANITIZER_OPTIONS
 ifneq ($(filter undefined,$(SANITIZERS)),)
 BASIC_CFLAGS += -DSHA1DC_FORCE_ALIGNED_ACCESS
 endif
diff --git a/common-main.c b/common-main.c
index 71e21dd20a..bff594ac04 100644
--- a/common-main.c
+++ b/common-main.c
@@ -2,6 +2,10 @@
 #include "exec-cmd.h"
 #include "attr.h"
 
+#ifdef ENABLE_CUSTOM_SANITIZER_OPTIONS
+#include <sanitizer/asan_interface.h>
+#endif
+
 /*
  * Many parts of Git have subprograms communicate via pipe, expect the
  * upstream of a pipe to die with SIGPIPE when the downstream of a
@@ -23,6 +27,18 @@ static void restore_sigpipe_to_default(void)
 	signal(SIGPIPE, SIG_DFL);
 }
 
+static void handle_custom_sanitizer_options(void)
+{
+#ifdef ENABLE_CUSTOM_SANITIZER_OPTIONS
+	const char *v;
+	v = getenv("GIT_SANITIZER_FD");
+	if (v) {
+		/* weird int-as-void interface from libsanitizer */
+		__sanitizer_set_report_fd((void *)(intptr_t)atoi(v));
+	}
+#endif
+}
+
 int main(int argc, const char **argv)
 {
 	int result;
@@ -37,6 +53,8 @@ int main(int argc, const char **argv)
 	sanitize_stdfds();
 	restore_sigpipe_to_default();
 
+	handle_custom_sanitizer_options();
+
 	git_resolve_executable_dir(argv[0]);
 
 	git_setup_gettext();
diff --git a/t/test-lib.sh b/t/test-lib.sh
index 62627afeaf..674bd30c44 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -54,22 +54,16 @@ then
 	# checking.
 	LSAN_OPTIONS=abort_on_error=1
 else
-	# The test script has possible LSAN failures. Just disable
-	# leak-checking entirely. Another option would be to log the failures
-	# with:
-	#
-	#   LSAN_OPTIONS=exitcode=0:log_path=$TEST_DIRECTORY/lsan/out
-	#
-	# The results are rather confusing, though, as the logs are
-	# per-process; you have no idea which one came from which test script.
-	# Ideally we'd send them to descriptor 4 along with the rest of the
-	# script log, but there's no LSAN_OPTION for that (recent versions of
-	# libsanitizer do have a public function to do so, so we could hook it
-	# ourselves via common-main).
-	LSAN_OPTIONS=detect_leaks=0
+	# The test script has possible LSAN failures. Just log them but don't
+	# touch the exit code.
+	LSAN_OPTIONS=exitcode=0
 fi
 export LSAN_OPTIONS
 
+# If we do generate output, try to avoid it getting tangled up with stderr.
+GIT_SANITIZER_FD=4
+export GIT_SANITIZER_FD
+
 if test ! -f "$GIT_BUILD_DIR"/GIT-BUILD-OPTIONS
 then
 	echo >&2 'error: GIT-BUILD-OPTIONS missing (has Git been built?).'
@@ -463,6 +457,7 @@ unset VISUAL EMAIL LANGUAGE $("$PERL_PATH" -e '
 		PERF_
 		CURL_VERBOSE
 		TRACE_CURL
+		SANITIZER_.*
 	));
 	my @vars = grep(/^GIT_/ && !/^GIT_($ok)/o, @env);
 	print join("\n", @vars);