Commit-ID: d2818df168b2c80c7449e47bd349094c308fa323
Gitweb: http://git.kernel.org/tip/d2818df168b2c80c7449e47bd349094c308fa323
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
AuthorDate: Tue, 23 Apr 2013 17:05:42 -0700
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Tue, 20 Aug 2013 11:37:54 -0700
rcu: Add duplicate-callback tests to rcutorture
This commit adds a object_debug option to rcutorture to allow the
debug-object-based checks for duplicate call_rcu() invocations to
be deterministically tested.
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
Cc: Sedat Dilek <sedat.dilek@xxxxxxxxx>
Cc: Davidlohr Bueso <davidlohr.bueso@xxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Tested-by: Sedat Dilek <sedat.dilek@xxxxxxxxx>
[ paulmck: Banish mid-function ifdef, more or less per Josh Triplett. ]
Reviewed-by: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
[ paulmck: Improve duplicate-callback test, per Lai Jiangshan. ]
---
kernel/rcutorture.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 61 insertions(+)
diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c
index 3d936f0f..c898f14 100644
--- a/kernel/rcutorture.c
+++ b/kernel/rcutorture.c
@@ -66,6 +66,7 @@ static int fqs_duration; /* Duration of bursts (us), 0 to disable. */
static int fqs_holdoff; /* Hold time within burst (us). */
static int fqs_stutter = 3; /* Wait time between bursts (s). */
static int n_barrier_cbs; /* Number of callbacks to test RCU barriers. */
+static int object_debug; /* Test object-debug double call_rcu()?. */
static int onoff_interval; /* Wait time between CPU hotplugs, 0=disable. */
static int onoff_holdoff; /* Seconds after boot before CPU hotplugs. */
static int shutdown_secs; /* Shutdown time (s). <=0 for no shutdown. */
@@ -100,6 +101,8 @@ module_param(fqs_stutter, int, 0444);
MODULE_PARM_DESC(fqs_stutter, "Wait time between fqs bursts (s)");
module_param(n_barrier_cbs, int, 0444);
MODULE_PARM_DESC(n_barrier_cbs, "# of callbacks/kthreads for barrier testing");
+module_param(object_debug, int, 0444);
+MODULE_PARM_DESC(object_debug, "Enable debug-object double call_rcu() testing");
module_param(onoff_interval, int, 0444);
MODULE_PARM_DESC(onoff_interval, "Time between CPU hotplugs (s), 0=disable");
module_param(onoff_holdoff, int, 0444);
@@ -1934,6 +1937,62 @@ rcu_torture_cleanup(void)
rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
}
+#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
+static void rcu_torture_leak_cb(struct rcu_head *rhp)
+{
+}
+
+static void rcu_torture_err_cb(struct rcu_head *rhp)
+{
+ /*
+ * This -might- happen due to race conditions, but is unlikely.
+ * The scenario that leads to this happening is that the
+ * first of the pair of duplicate callbacks is queued,
+ * someone else starts a grace period that includes that
+ * callback, then the second of the pair must wait for the
+ * next grace period. Unlikely, but can happen. If it
+ * does happen, the debug-objects subsystem won't have splatted.
+ */
+ pr_alert("rcutorture: duplicated callback was invoked.\n");
+}
+#endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
+
+/*
+ * Verify that double-free causes debug-objects to complain, but only
+ * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test
+ * cannot be carried out.
+ */
+static void rcu_test_debug_objects(void)
+{
+#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
+ struct rcu_head rh1;
+ struct rcu_head rh2;
+
+ init_rcu_head_on_stack(&rh1);
+ init_rcu_head_on_stack(&rh2);
+ pr_alert("rcutorture: WARN: Duplicate call_rcu() test starting.\n");
+
+ /* Try to queue the rh2 pair of callbacks for the same grace period. */
+ preempt_disable(); /* Prevent preemption from interrupting test. */
+ rcu_read_lock(); /* Make it impossible to finish a grace period. */
+ call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */
+ local_irq_disable(); /* Make it harder to start a new grace period. */
+ call_rcu(&rh2, rcu_torture_leak_cb);
+ call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
+ local_irq_enable();
+ rcu_read_unlock();
+ preempt_enable();
+
+ /* Wait for them all to get done so we can safely return. */
+ rcu_barrier();
+ pr_alert("rcutorture: WARN: Duplicate call_rcu() test complete.\n");
+ destroy_rcu_head_on_stack(&rh1);
+ destroy_rcu_head_on_stack(&rh2);
+#else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
+ pr_alert("rcutorture: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n");
+#endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
+}
+
static int __init
rcu_torture_init(void)
{
@@ -2163,6 +2222,8 @@ rcu_torture_init(void)
firsterr = retval;
goto unwind;
}
+ if (object_debug)
+ rcu_test_debug_objects();
rcutorture_record_test_transition();
mutex_unlock(&fullstop_mutex);
return 0;
--
To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
|