rcutorture: Allow pointer leaks to test diagnostic code

This commit adds an rcutorture.leakpointer module parameter that
intentionally leaks an RCU-protected pointer out of the RCU read-side
critical section and checks to see if the corresponding grace period
has elapsed, emitting a WARN_ON_ONCE() if so.  This module parameter can
be used to test facilities like CONFIG_RCU_STRICT_GRACE_PERIOD that end
grace periods quickly.

While in the area, also document rcutorture.irqreader, which was
previously left out.

Reported-by Jann Horn <jannh@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Paul E. McKenney
2020-08-11 10:33:39 -07:00
parent 299c7d94f6
commit d685514260
2 changed files with 16 additions and 0 deletions

View File

@@ -4269,6 +4269,18 @@
are zero, rcutorture acts as if is interpreted
they are all non-zero.
rcutorture.irqreader= [KNL]
Run RCU readers from irq handlers, or, more
accurately, from a timer handler. Not all RCU
flavors take kindly to this sort of thing.
rcutorture.leakpointer= [KNL]
Leak an RCU-protected pointer out of the reader.
This can of course result in splats, and is
intended to test the ability of things like
CONFIG_RCU_STRICT_GRACE_PERIOD=y to detect
such leaks.
rcutorture.n_barrier_cbs= [KNL]
Set callbacks/threads for rcu_barrier() testing.