linux-kernel - [PATCH tip/core/rcu 05/21] torture: Allow inter-stutter interval to be specified

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 30 May 2019 08:16:56 -0700
From:   "Paul E. McKenney" <paulmck@...ux.ibm.com>
To:     rcu@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, mingo@...nel.org,
        jiangshanlai@...il.com, dipankar@...ibm.com,
        akpm@...ux-foundation.org, mathieu.desnoyers@...icios.com,
        josh@...htriplett.org, tglx@...utronix.de, peterz@...radead.org,
        rostedt@...dmis.org, dhowells@...hat.com, edumazet@...gle.com,
        fweisbec@...il.com, oleg@...hat.com, joel@...lfernandes.org,
        "Paul E. McKenney" <paulmck@...ux.ibm.com>
Subject: [PATCH tip/core/rcu 05/21] torture: Allow inter-stutter interval to be specified

Currently, the inter-stutter interval is the same as the stutter duration,
that is, whatever number of jiffies is passed into torture_stutter_init().
This has worked well for quite some time, but the addition of
forward-progress testing to rcutorture can delay processes for several
seconds, which can triple the time that they are stuttered.

This commit therefore adds a second argument to torture_stutter_init()
that specifies the inter-stutter interval.  While locktorture preserves
the current behavior, rcutorture uses the RCU CPU stall warning interval
to provide a wider inter-stutter interval.

Signed-off-by: Paul E. McKenney <paulmck@...ux.ibm.com>
---
 include/linux/torture.h      | 2 +-
 kernel/locking/locktorture.c | 2 +-
 kernel/rcu/rcutorture.c      | 5 ++++-
 kernel/torture.c             | 6 ++++--
 4 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/include/linux/torture.h b/include/linux/torture.h
index 23d80db426d7..a620118385bb 100644
--- a/include/linux/torture.h
+++ b/include/linux/torture.h
@@ -66,7 +66,7 @@ int torture_shutdown_init(int ssecs, void (*cleanup)(void));
 
 /* Task stuttering, which forces load/no-load transitions. */
 bool stutter_wait(const char *title);
-int torture_stutter_init(int s);
+int torture_stutter_init(int s, int sgap);
 
 /* Initialization and cleanup. */
 bool torture_init_begin(char *ttype, int v);
diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index 80a463d31a8d..c513031cd7e3 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -975,7 +975,7 @@ static int __init lock_torture_init(void)
 			goto unwind;
 	}
 	if (stutter > 0) {
-		firsterr = torture_stutter_init(stutter);
+		firsterr = torture_stutter_init(stutter, stutter);
 		if (firsterr)
 			goto unwind;
 	}
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 954ac2b98619..a16d6abe1715 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -2373,7 +2373,10 @@ rcu_torture_init(void)
 	if (stutter < 0)
 		stutter = 0;
 	if (stutter) {
-		firsterr = torture_stutter_init(stutter * HZ);
+		int t;
+
+		t = cur_ops->stall_dur ? cur_ops->stall_dur() : stutter * HZ;
+		firsterr = torture_stutter_init(stutter * HZ, t);
 		if (firsterr)
 			goto unwind;
 	}
diff --git a/kernel/torture.c b/kernel/torture.c
index de0e0ecf88e1..a8d9bdfba7c3 100644
--- a/kernel/torture.c
+++ b/kernel/torture.c
@@ -570,6 +570,7 @@ static void torture_shutdown_cleanup(void)
 static struct task_struct *stutter_task;
 static int stutter_pause_test;
 static int stutter;
+static int stutter_gap;
 
 /*
  * Block until the stutter interval ends.  This must be called periodically
@@ -621,7 +622,7 @@ static int torture_stutter(void *arg)
 		}
 		WRITE_ONCE(stutter_pause_test, 0);
 		if (!torture_must_stop())
-			schedule_timeout_interruptible(stutter);
+			schedule_timeout_interruptible(stutter_gap);
 		torture_shutdown_absorb("torture_stutter");
 	} while (!torture_must_stop());
 	torture_kthread_stopping("torture_stutter");
@@ -631,9 +632,10 @@ static int torture_stutter(void *arg)
 /*
  * Initialize and kick off the torture_stutter kthread.
  */
-int torture_stutter_init(const int s)
+int torture_stutter_init(const int s, const int sgap)
 {
 	stutter = s;
+	stutter_gap = sgap;
 	return torture_create_kthread(torture_stutter, NULL, stutter_task);
 }
 EXPORT_SYMBOL_GPL(torture_stutter_init);
-- 
2.17.1