On Sat, Aug 17, 2013 at 07:25:13PM -0700, Paul E. McKenney wrote:
> From: "Paul E. McKenney" <paul...@linux.vnet.ibm.com>
>
> This commit adds a object_debug option to rcutorture to allow the
> debug-object-based checks for duplicate call_rcu() invocations to
> be deterministically tested.
>
> Signed-off-by: Paul E. McKenney <paul...@linux.vnet.ibm.com>
> Cc: Mathieu Desnoyers <mathieu.desnoy...@efficios.com>
> Cc: Sedat Dilek <sedat.di...@gmail.com>
> Cc: Davidlohr Bueso <davidlohr.bu...@hp.com>
> Cc: Rik van Riel <r...@surriel.com>
> Cc: Thomas Gleixner <t...@linutronix.de>
> Cc: Linus Torvalds <torva...@linux-foundation.org>
> Tested-by: Sedat Dilek <sedat.di...@gmail.com>
Two comments below; with those fixed,
Reviewed-by: Josh Triplett <j...@joshtriplett.org>
> ---
> @@ -100,6 +101,8 @@ module_param(fqs_stutter, int, 0444);
> MODULE_PARM_DESC(fqs_stutter, "Wait time between fqs bursts (s)");
> module_param(n_barrier_cbs, int, 0444);
> MODULE_PARM_DESC(n_barrier_cbs, "# of callbacks/kthreads for barrier
> testing");
> +module_param(object_debug, int, 0444);
> +MODULE_PARM_DESC(object_debug, "Enable debug-object double call_rcu()
> testing");
modules-next has a change to ignore and warn about
unknown module parameters. Thus, I'd suggest wrapping the ifdef around
this module parameter, so it doesn't exist at all without
CONFIG_DEBUG_OBJECTS_RCU_HEAD.
Alternatively, consider providing the test unconditionally, and just
printing a big warning message saying that it's going to cause
corruption in the !CONFIG_DEBUG_OBJECTS_RCU_HEAD case.
> @@ -2163,6 +2178,28 @@ rcu_torture_init(void)
> firsterr = retval;
> goto unwind;
> }
> + if (object_debug) {
> +#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
> + struct rcu_head rh1;
> + struct rcu_head rh2;
> +
> + init_rcu_head_on_stack(&rh1);
> + init_rcu_head_on_stack(&rh2);
> + pr_alert("rcutorture: WARN: Duplicate call_rcu() test
> starting.\n");
> + local_irq_disable(); /* Make it hard to finish grace period. */
> + call_rcu(&rh1, rcu_torture_leak_cb); /* start grace period. */
> + call_rcu(&rh2, rcu_torture_err_cb);
> + call_rcu(&rh2, rcu_torture_err_cb); /* duplicate callback. */
> + local_irq_enable();
> + rcu_barrier();
> + pr_alert("rcutorture: WARN: Duplicate call_rcu() test
> complete.\n");
> + destroy_rcu_head_on_stack(&rh1);
> + destroy_rcu_head_on_stack(&rh2);
> +#else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
> + pr_alert("rcutorture: !%s, not testing duplicate call_rcu()\n",
> + "CONFIG_DEBUG_OBJECTS_RCU_HEAD");
Why put this parameter in a separate string? That makes it harder to
grep for the full error message. (That's assuming you keep the error
message, given the comment above.)
- Josh Triplett
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