[RFC PATCH 2/2] futex: hack: Add debug delays

[André Almeida]

Add delays to handle_futex_death() to increase the chance of hitting the race
condition.

Signed-off-by: André Almeida <andrealmeid@xxxxxxxxxx>
---
 kernel/futex/core.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/kernel/futex/core.c b/kernel/futex/core.c
index cf7e610eac42..d409b3368cb3 100644
--- a/kernel/futex/core.c
+++ b/kernel/futex/core.c
@@ -44,6 +44,7 @@
 #include <linux/prctl.h>
 #include <linux/mempolicy.h>
 #include <linux/mmap_lock.h>
+#include <linux/delay.h>
 
 #include "futex.h"
 #include "../locking/rtmutex_common.h"
@@ -1095,6 +1096,12 @@ static int handle_futex_death(u32 __user *uaddr, struct task_struct *curr,
 	 * does not guarantee R/W access. If that fails we
 	 * give up and leave the futex locked.
 	 */
+
+	if (!strcmp(current->comm, "robust_bug")) {
+		printk("robust_bug is exiting\n");
+		msleep(500);
+	}
+
 	if ((err = futex_cmpxchg_value_locked(&nval, uaddr, uval, mval))) {
 		switch (err) {
 		case -EFAULT:
@@ -1112,6 +1119,9 @@ static int handle_futex_death(u32 __user *uaddr, struct task_struct *curr,
 		}
 	}
 
+	if (!strcmp(current->comm, "robust_bug"))
+		printk("memory written\n");
+
 	if (nval != uval)
 		goto retry;
 
-- 
2.53.0