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authorMartin Ågren <martin.agren@gmail.com>2017-08-21 19:43:48 +0200
committerJunio C Hamano <gitster@pobox.com>2017-08-23 10:38:56 -0700
commit6cdf8a7929688ea5702ab53f450d038e973e64e1 (patch)
tree6bc1c2972542be1c7ada97faefa345278b582c7e
parent65961d5a75e28aa04a90ee65106f71da177fd4b3 (diff)
downloadgit-6cdf8a7929688ea5702ab53f450d038e973e64e1.tar.gz
ThreadSanitizer: add suppressionsma/ts-cleanups
Add a file .tsan-suppressions and list two functions in it: want_color() and transfer_debug(). Both of these use the pattern static int foo = -1; if (foo < 0) foo = bar(); where bar always returns the same non-negative value. This can cause ThreadSanitizer to diagnose a race when foo is written from two threads. That is indeed a race, although it arguably doesn't matter in practice since it's always the same value that is written. Add NEEDSWORK-comments to the functions so that this problem is not forever swept way under the carpet. The suppressions-file is used by setting the environment variable TSAN_OPTIONS to, e.g., "suppressions=$(pwd)/.tsan-suppressions". Observe that relative paths such as ".tsan-suppressions" might not work. Signed-off-by: Martin Ågren <martin.agren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
-rw-r--r--.tsan-suppressions10
-rw-r--r--color.c7
-rw-r--r--transport-helper.c7
3 files changed, 24 insertions, 0 deletions
diff --git a/.tsan-suppressions b/.tsan-suppressions
new file mode 100644
index 0000000000..8c85014a0a
--- /dev/null
+++ b/.tsan-suppressions
@@ -0,0 +1,10 @@
+# Suppressions for ThreadSanitizer (tsan).
+#
+# This file is used by setting the environment variable TSAN_OPTIONS to, e.g.,
+# "suppressions=$(pwd)/.tsan-suppressions". Observe that relative paths such as
+# ".tsan-suppressions" might not work.
+
+# A static variable is written to racily, but we always write the same value, so
+# in practice it (hopefully!) doesn't matter.
+race:^want_color$
+race:^transfer_debug$
diff --git a/color.c b/color.c
index 31b6207a00..9a9261ac16 100644
--- a/color.c
+++ b/color.c
@@ -338,6 +338,13 @@ static int check_auto_color(void)
int want_color(int var)
{
+ /*
+ * NEEDSWORK: This function is sometimes used from multiple threads, and
+ * we end up using want_auto racily. That "should not matter" since
+ * we always write the same value, but it's still wrong. This function
+ * is listed in .tsan-suppressions for the time being.
+ */
+
static int want_auto = -1;
if (var < 0)
diff --git a/transport-helper.c b/transport-helper.c
index 33cff38cc0..2b830b2290 100644
--- a/transport-helper.c
+++ b/transport-helper.c
@@ -1117,6 +1117,13 @@ int transport_helper_init(struct transport *transport, const char *name)
__attribute__((format (printf, 1, 2)))
static void transfer_debug(const char *fmt, ...)
{
+ /*
+ * NEEDSWORK: This function is sometimes used from multiple threads, and
+ * we end up using debug_enabled racily. That "should not matter" since
+ * we always write the same value, but it's still wrong. This function
+ * is listed in .tsan-suppressions for the time being.
+ */
+
va_list args;
char msgbuf[PBUFFERSIZE];
static int debug_enabled = -1;