[igt-dev] [PATCH i-g-t] lib: Don't leak children in igt_waitchildren_timeout

Daniel Vetter
2019-02-12T16:02:20Z

Instead of cleaning up the mess in igt_exit make sure we don't even
let it out of the container. See also

commit 754876378d6c9b2775e8c07b4d16f9878c55949f
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date: Fri Feb 26 22:11:10 2016 +0000

igt/gem_sync: Enforce a timeout of 20s

which added this helper.

To make sure that everyone follows the rules, add an assert.

We're keeping the cleanup code as a failsafe, and because it speeds
up the testcase I'm following up with.

v2: Chris pointed out that my original patch did nothing. Which I
didn't catch because my testcase was also broken. Unfortunately this
means we need to open code part of the waiting.

v3: The 2nd __igt_waitchildren() isn't necessary, __igt_waitchildren
recovers from EINTR already and keeps waiting (Chris Wilson).

v4: Change the timeout signal vs waitchildren logic to be race-free
(Chris). This changes the exit code for a timeout from
IGT_EXIT_FAILURE to SIGKILL + 128.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
---
lib/igt_core.c | 30 +++++++++++++++++++++++++-----
1 file changed, 25 insertions(+), 5 deletions(-)

diff --git a/lib/igt_core.c b/lib/igt_core.c
index cbbe79f88070..57f757421309 100644
--- a/lib/igt_core.c
+++ b/lib/igt_core.c
@@ -1525,6 +1525,7 @@ void igt_exit(void)

for (int c = 0; c < num_test_children; c++)
kill(test_children[c], SIGKILL);
+ assert(!num_test_children);

if (!test_with_subtests) {
struct timespec now;
@@ -1832,20 +1833,39 @@ void igt_waitchildren(void)
igt_fail(err);
}

+static void igt_alarm_killchildren(int signal)
+{
+ igt_info("Timed out waiting for children\n");
+
+ for (int c = 0; c < num_test_children; c++)
+ kill(test_children[c], SIGKILL);
+}
+
/**
* igt_waitchildren_timeout:
* @seconds: timeout in seconds to wait
* @reason: debug string explaining what timedout
*
- * Wait for all children forked with igt_fork, for a maximum of @seconds.
- *
- * Wraps igt_waitchildren() and igt_set_timeout()
+ * Wait for all children forked with igt_fork, for a maximum of @seconds. If the
+ * timeout expires, kills all children and cleans them up.
*/
void igt_waitchildren_timeout(int seconds, const char *reason)
{
- igt_set_timeout(seconds, reason);
- igt_waitchildren();
+ struct sigaction sa;
+ int ret;
+
+ sa.sa_handler = igt_alarm_killchildren;
+ sigemptyset(&sa.sa_mask);
+ sa.sa_flags = 0;
+
+ sigaction(SIGALRM, &sa, NULL);
+
+ alarm(seconds);
+
+ ret = __igt_waitchildren();
igt_reset_timeout();
+ if (ret)
+ igt_fail(ret);
}

/* exit handler code */
--
2.20.1