Re: [PATCH tip/core/rcu 2/3] rcutorture: Test both RCU-sched and RCU-bh for Tiny RCU

["Paul E. McKenney" <paulmck@linux.vnet.ibm.com>]

On Tue, May 12, 2015 at 05:59:29PM -0700, josh@joshtriplett.org wrote:
> On Tue, May 12, 2015 at 03:49:12PM -0700, Paul E. McKenney wrote:
> > From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
> > 
> > Reported-by: "Ahmed, Iftekhar" <ahmedi@onid.oregonstate.edu>
> > Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> 
> Could you elaborate a bit more on this patch (ideally in its commit
> message)?  I see an addition of a command-line parameter to test rcu_bh;
> is rcu-sched already tested elsewhere by some other config, or does this
> parameter somehow enable testing both?

The commit log now reads as follows, does that help?

							Thanx, Paul

------------------------------------------------------------------------

rcutorture: Test both RCU-sched and RCU-bh for Tiny RCU

Tiny RCU supports both RCU-sched and RCU-bh, but only RCU-sched is
currently tested by the rcutorture scripts.  This commit therefore
changes the TINY02 configuration to test RCU-bh, with TINY01 continuing
to test RCU-sched.

This shortcoming of the current rcutorture tests was located by mutation
testing by Iftekhar.  The idea behind mutation testing is to automatically
mutate the code under test.  If a given mutant is not caught by testing,
this is a hint that the testing might need to be improved, as was the
case here.  Note that this is only a hint because it is possible to mutate
the code into something else that still works.  For example, a mutation
that removes (say) a WARN_ON() will not normally result in a test failure.

This change resulted in the test failure caused by list mishandling,
which is fixed by the next commit.

Reported-by: "Ahmed, Iftekhar" <ahmedi@onid.oregonstate.edu>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>