linux/tools/memory-model/litmus-tests/MP+onceassign+derefonce.litmus
Paul E. McKenney 8f32543b61 EXP litmus_tests: Add comments explaining tests' purposes
This commit adds comments to the litmus tests summarizing what these
tests are intended to demonstrate.

[ paulmck: Apply Andrea's and Alan's feedback. ]
Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: akiyks@gmail.com
Cc: boqun.feng@gmail.com
Cc: dhowells@redhat.com
Cc: j.alglave@ucl.ac.uk
Cc: linux-arch@vger.kernel.org
Cc: luc.maranget@inria.fr
Cc: nborisov@suse.com
Cc: npiggin@gmail.com
Cc: parri.andrea@gmail.com
Cc: stern@rowland.harvard.edu
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1519169112-20593-4-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-02-21 09:58:13 +01:00

35 lines
555 B
Plaintext

C MP+onceassign+derefonce
(*
* Result: Never
*
* This litmus test demonstrates that rcu_assign_pointer() and
* rcu_dereference() suffice to ensure that an RCU reader will not see
* pre-initialization garbage when it traverses an RCU-protected data
* structure containing a newly inserted element.
*)
{
y=z;
z=0;
}
P0(int *x, int **y)
{
WRITE_ONCE(*x, 1);
rcu_assign_pointer(*y, x);
}
P1(int *x, int **y)
{
int *r0;
int r1;
rcu_read_lock();
r0 = rcu_dereference(*y);
r1 = READ_ONCE(*r0);
rcu_read_unlock();
}
exists (1:r0=x /\ 1:r1=0)