[PATCH v2 1/2] kobject: delay kobject release for random time

From: Bjorn Helgaas
Date: Thu Dec 05 2013 - 19:38:06 EST


When CONFIG_DEBUG_KOBJECT_RELEASE=y, delay kobject release functions for a
random time between 1 and 8 seconds, which effectively changes the order in
which they're called.

Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
---
lib/kobject.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/lib/kobject.c b/lib/kobject.c
index 962175134702..bc73312ac797 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -17,6 +17,7 @@
#include <linux/export.h>
#include <linux/stat.h>
#include <linux/slab.h>
+#include <linux/random.h>

/*
* populate_dir - populate directory with attributes.
@@ -592,10 +593,13 @@ static void kobject_release(struct kref *kref)
{
struct kobject *kobj = container_of(kref, struct kobject, kref);
#ifdef CONFIG_DEBUG_KOBJECT_RELEASE
- pr_debug("kobject: '%s' (%p): %s, parent %p (delayed)\n",
- kobject_name(kobj), kobj, __func__, kobj->parent);
+ unsigned long delay = HZ + HZ * (get_random_int() & 0x3);
+
+ pr_debug("kobject: '%s' (%p): %s, parent %p (delayed %ld)\n",
+ kobject_name(kobj), kobj, __func__, kobj->parent, delay);
INIT_DELAYED_WORK(&kobj->release, kobject_delayed_cleanup);
- schedule_delayed_work(&kobj->release, HZ);
+
+ schedule_delayed_work(&kobj->release, delay);
#else
kobject_cleanup(kobj);
#endif

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