[PATCH v4 linux-kselftest-test 4/6] kunit: remove timeout dependence on sysctl_hung_task_timeout_seconds

Alan Maguire
2019-11-15T10:18:08Z

In discussion of how to handle timeouts, it was noted that if
sysctl_hung_task_timeout_seconds is exceeded for a kunit test,
the test task will be killed and an oops generated. This should
suffice as a means of debugging such timeout issues for now.

Hence remove use of sysctl_hung_task_timeout_secs, which has the
added benefit of avoiding the need to export that symbol from
the core kernel.

Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Knut Omang <knut.omang@oracle.com>
---
lib/kunit/try-catch.c | 22 ++++------------------
1 file changed, 4 insertions(+), 18 deletions(-)

diff --git a/lib/kunit/try-catch.c b/lib/kunit/try-catch.c
index 0247a28..0dd434e 100644
--- a/lib/kunit/try-catch.c
+++ b/lib/kunit/try-catch.c
@@ -11,7 +11,6 @@
#include <linux/completion.h>
#include <linux/kernel.h>
#include <linux/kthread.h>
-#include <linux/sched/sysctl.h>

#include "try-catch-impl.h"

@@ -33,8 +32,6 @@ static int kunit_generic_run_threadfn_adapter(void *data)

static unsigned long kunit_test_timeout(void)
{
- unsigned long timeout_msecs;
-
/*
* TODO(brendanhiggins@google.com): We should probably have some type of
* variable timeout here. The only question is what that timeout value
@@ -51,22 +48,11 @@ static unsigned long kunit_test_timeout(void)
*
* For more background on this topic, see:
* https://mike-bland.com/2011/11/01/small-medium-large.html
+ *
+ * If tests timeout due to exceeding sysctl_hung_task_timeout_secs,
+ * the task will be killed and an oops generated.
*/
- if (sysctl_hung_task_timeout_secs) {
- /*
- * If sysctl_hung_task is active, just set the timeout to some
- * value less than that.
- *
- * In regards to the above TODO, if we decide on variable
- * timeouts, this logic will likely need to change.
- */
- timeout_msecs = (sysctl_hung_task_timeout_secs - 1) *
- MSEC_PER_SEC;
- } else {
- timeout_msecs = 300 * MSEC_PER_SEC; /* 5 min */
- }
-
- return timeout_msecs;
+ return 300 * MSEC_PER_SEC; /* 5 min */
}

void kunit_try_catch_run(struct kunit_try_catch *try_catch, void *context)
--
1.8.3.1