From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754375Ab3HRCyi (ORCPT ); Sat, 17 Aug 2013 22:54:38 -0400 Received: from relay4-d.mail.gandi.net ([217.70.183.196]:51777 "EHLO relay4-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752958Ab3HRCyh (ORCPT ); Sat, 17 Aug 2013 22:54:37 -0400 X-Originating-IP: 50.43.39.152 Date: Sat, 17 Aug 2013 19:54:20 -0700 From: Josh Triplett To: "Paul E. McKenney" Cc: linux-kernel@vger.kernel.org, mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, darren@dvhart.com, fweisbec@gmail.com, sbw@mit.edu, Mathieu Desnoyers , Sedat Dilek , Davidlohr Bueso , Rik van Riel , Linus Torvalds Subject: Re: [PATCH tip/core/rcu 1/5] rcu: Add duplicate-callback tests to rcutorture Message-ID: <20130818025420.GC28923@leaf> References: <20130818022453.GA3475@linux.vnet.ibm.com> <1376792717-3755-1-git-send-email-paulmck@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1376792717-3755-1-git-send-email-paulmck@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Aug 17, 2013 at 07:25:13PM -0700, Paul E. McKenney wrote: > From: "Paul E. McKenney" > > 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 > Cc: Mathieu Desnoyers > Cc: Sedat Dilek > Cc: Davidlohr Bueso > Cc: Rik van Riel > Cc: Thomas Gleixner > Cc: Linus Torvalds > Tested-by: Sedat Dilek Two comments below; with those fixed, Reviewed-by: Josh Triplett > --- > @@ -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