linux/kernel/torture.c, branch v3.15

rcutorture: Gracefully handle NULL cleanup hooks

2014-02-23T17:04:39Z

Although most torture tests will have some cleanup hook, it is possible that one might not. This commit therefore enables graceful handling of a NULL cleanup hook during torture-test shutdown. Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett

rcutorture: Stop generic kthreads in torture_cleanup()

2014-02-23T17:04:27Z

The specific torture modules (like rcutorture) need to call torture_cleanup() in any case, so this commit makes torture_cleanup() deal with torture_shutdown_cleanup() and torture_stutter_cleanup() so that the specific modules don't have to deal with these details. Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett

rcutorture: Abstract torture_stop_kthread()

2014-02-23T17:04:25Z

Stopping of kthreads is not RCU-specific, so this commit abstracts out torture_stop_kthread(), saving a few lines of code in the process. Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett

rcutorture: Abstract torture_create_kthread()

2014-02-23T17:03:24Z

Creation of kthreads is not RCU-specific, so this commit abstracts out torture_create_kthread(), saving a few tens of lines of code in the process. This change requires modifying VERBOSE_TOROUT_ERRSTRING() to take a non-const string, so that _torture_create_kthread() can avoid an open-coded substitute. Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett

rcutorture: Fix rcutorture shutdown races

2014-02-23T17:03:21Z

Not all of the rcutorture kthreads waited for kthread_should_stop() before returning from their top-level functions, and none of them used torture_shutdown_absorb() properly. These problems can result in segfaults and hangs at shutdown time, and some recent changes perturbed timing sufficiently to make them much more probable. This commit therefore creates a torture_kthread_stopping() function that does the proper kthread shutdown dance in one centralized location. Accommodate this grouping by making VERBOSE_TOROUT_STRING() capable of taking a non-const string as its argument, which allows the new torture_kthread_stopping() to pass its "title" argument directly to the updated version of VERBOSE_TOROUT_STRING(). Signed-off-by: Paul E. McKenney

rcutorture: Announce task creation

2014-02-23T17:03:20Z

A few "stealth-start rcutorture kthreads" have accumulated over the years, so this commit adds console-log announcements (but only if the torture tests are running verbose). Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett

rcutorture: Abstract torture_shutdown()

2014-02-23T17:03:18Z

Because auto-shutdown of torture testing is not specific to RCU, this commit moves the auto-shutdown function to kernel/torture.c. Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett

rcutorture: Apply ACCESS_ONCE() to racy fullstop accesses

2014-02-23T17:03:16Z

Because the fullstop variable can be accessed while it is being updated, this commit avoids any resulting compiler mischief through use of ACCESS_ONCE() for non-initialization accesses to this shared variable. Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett

rcutorture: Abstract stutter_wait()

2014-02-23T17:02:54Z

Because stuttering the test load (stopping and restarting it) is useful for non-RCU testing, this commit moves the load-stuttering functionality to kernel/torture.c. Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett

rcutorture: Add diagnostic for unscheduled system shutdown

2014-02-23T17:01:13Z

Currently, rcutorture can terminate via rmmod, via self-shutdown, via something else shutting the system down, or of course the usual catastrophic termination. The first two get flagged, so this commit adds a message for the third. For the fourth, your warranty is void as always. Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett