Avoid that pthread_cancel(ct->thread) can get called after the TUR
thread exited because this is not allowed for detached threads.
Avoid that data-race detection tools complain about reading ct->thread
without holding ct->hldr_lock.
Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
---
libmultipath/checkers/tur.c | 24 +++++++++++++++++++++---
1 file changed, 21 insertions(+), 3 deletions(-)
diff --git a/libmultipath/checkers/tur.c b/libmultipath/checkers/tur.c
index 7605fb9..a7a70f6 100644
--- a/libmultipath/checkers/tur.c
+++ b/libmultipath/checkers/tur.c
@@ -224,6 +224,17 @@ static void cleanup_func(void *data)
cleanup_context(ct);
}
+static int tur_running(struct tur_checker_context *ct)
+{
+ pthread_t thread;
+
+ pthread_spin_lock(&ct->hldr_lock);
+ thread = ct->thread;
+ pthread_spin_unlock(&ct->hldr_lock);
+
+ return thread != 0;
+}
+
static void copy_msg_to_tcc(void *ct_p, const char *msg)
{
struct tur_checker_context *ct = ct_p;
@@ -334,7 +345,13 @@ libcheck_check (struct checker * c)
}
if (ct->running) {
- /* Check if TUR checker is still running */
+ /*
+ * Check if TUR checker is still running. Hold hldr_lock
+ * around the pthread_cancel() call to avoid that
+ * pthread_cancel() gets called after the (detached) TUR
+ * thread has exited.
+ */
+ pthread_spin_lock(&ct->hldr_lock);
if (ct->thread) {
if (tur_check_async_timeout(c)) {
condlog(3, "%s: tur checker timeout",
@@ -355,9 +372,10 @@ libcheck_check (struct checker * c)
tur_status = ct->state;
strlcpy(c->message, ct->message, sizeof(c->message));
}
+ pthread_spin_unlock(&ct->hldr_lock);
pthread_mutex_unlock(&ct->lock);
} else {
- if (ct->thread) {
+ if (tur_running(ct)) {
/* pthread cancel failed. continue in sync mode */
pthread_mutex_unlock(&ct->lock);
condlog(3, "%s: tur thread not responding",
@@ -391,7 +409,7 @@ libcheck_check (struct checker * c)
tur_status = ct->state;
strlcpy(c->message, ct->message, sizeof(c->message));
pthread_mutex_unlock(&ct->lock);
- if (ct->thread &&
+ if (tur_running(ct) &&
(tur_status == PATH_PENDING || tur_status == PATH_UNCHECKED)) {
condlog(3, "%s: tur checker still running",
tur_devt(devt, sizeof(devt), ct));
--
2.10.0
--
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