From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 3292 invoked by alias); 24 Jan 2007 04:30:20 -0000 Received: (qmail 3170 invoked by uid 22791); 24 Jan 2007 04:30:17 -0000 X-Spam-Status: No, hits=-2.5 required=5.0 tests=AWL,BAYES_00,FORGED_RCVD_HELO,SPF_PASS X-Spam-Check-By: sourceware.org Received: from smtp.osdl.org (HELO smtp.osdl.org) (65.172.181.24) by sourceware.org (qpsmtpd/0.31) with ESMTP; Wed, 24 Jan 2007 04:30:09 +0000 Received: from shell0.pdx.osdl.net (fw.osdl.org [65.172.181.6]) by smtp.osdl.org (8.12.8/8.12.8) with ESMTP id l0O4TApa029899 (version=TLSv1/SSLv3 cipher=EDH-RSA-DES-CBC3-SHA bits=168 verify=NO); Tue, 23 Jan 2007 20:29:10 -0800 Received: from box (shell0.pdx.osdl.net [10.9.0.31]) by shell0.pdx.osdl.net (8.13.1/8.11.6) with SMTP id l0O4T99F008328; Tue, 23 Jan 2007 20:29:09 -0800 Date: Wed, 24 Jan 2007 04:30:00 -0000 From: Andrew Morton To: Mathieu Desnoyers Cc: Ingo Molnar , Greg Kroah-Hartman , Christoph Hellwig , linux-kernel@vger.kernel.org, ltt-dev@shafik.org, "Martin J. Bligh" , Douglas Niehaus , systemtap@sources.redhat.com, Thomas Gleixner , Richard J Moore Subject: Re: [PATCH 2/2] lockdep reentrancy Message-Id: <20070123202909.6b7dcd17.akpm@osdl.org> In-Reply-To: <20070116175631.GB16084@Krystal> References: <20061220235216.GA28643@Krystal> <20070116175631.GB16084@Krystal> X-Mailer: Sylpheed version 2.2.7 (GTK+ 2.8.17; x86_64-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Spam-Checker-Version: SpamAssassin 2.63-osdl_revision__1.108__ X-MIMEDefang-Filter: osdl$Revision: 1.171 $ X-Scanned-By: MIMEDefang 2.36 Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org X-SW-Source: 2007-q1/txt/msg00178.txt.bz2 On Tue, 16 Jan 2007 12:56:31 -0500 Mathieu Desnoyers wrote: > Here is a patch to lockdep.c so it behaves correctly when a kprobe breakpoint is > put on a marker within hardirq tracing functions as long as the marker is within > the lockdep_recursion incremented boundaries. It should apply on > 2.6.20-rc4-git3. > > Mathieu > > Signed-off-by: Mathieu Desnoyers > > > @@ -1841,33 +1843,36 @@ void trace_hardirqs_on(void) You lost the patch headers. > struct task_struct *curr = current; > unsigned long ip; > > if (unlikely(!debug_locks || current->lockdep_recursion)) > return; > > + current->lockdep_recursion++; > + barrier(); Why can't we use lockdep_off() here? > if (DEBUG_LOCKS_WARN_ON(unlikely(!early_boot_irqs_enabled))) > - return; > + goto end; > > if (unlikely(curr->hardirqs_enabled)) { > debug_atomic_inc(&redundant_hardirqs_on); > - return; > + goto end; > } > /* we'll do an OFF -> ON transition: */ > curr->hardirqs_enabled = 1; > ip = (unsigned long) __builtin_return_address(0); > > if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) > - return; > + goto end; > if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) > - return; > + goto end; > /* > * We are going to turn hardirqs on, so set the > * usage bit for all held locks: > */ > if (!mark_held_locks(curr, 1, ip)) > - return; > + goto end; > /* > * If we have softirqs enabled, then set the usage > * bit for all held locks. (disabled hardirqs prevented > @@ -1875,11 +1880,14 @@ void trace_hardirqs_on(void) > */ > if (curr->softirqs_enabled) > if (!mark_held_locks(curr, 0, ip)) > - return; > + goto end; > > curr->hardirq_enable_ip = ip; > curr->hardirq_enable_event = ++curr->irq_events; > debug_atomic_inc(&hardirqs_on_events); > +end: > + barrier(); > + current->lockdep_recursion--; lockdep_on()? > } > > EXPORT_SYMBOL(trace_hardirqs_on); > @@ -1888,14 +1896,17 @@ void trace_hardirqs_off(void) > { > struct task_struct *curr = current; > > if (unlikely(!debug_locks || current->lockdep_recursion)) > return; > > + current->lockdep_recursion++; > + barrier(); lockdep_off()? > if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) > - return; > + goto end; > > if (curr->hardirqs_enabled) { > /* > @@ -1910,6 +1921,9 @@ void trace_hardirqs_off(void) > debug_atomic_inc(&hardirqs_off_events); > } else > debug_atomic_inc(&redundant_hardirqs_off); > +end: > + barrier(); > + current->lockdep_recursion--; lockdep_on()?