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From: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
To: Ingo Molnar <mingo@redhat.com>
Cc: Andrew Morton <akpm@osdl.org>,
	Greg Kroah-Hartman <gregkh@suse.de>,
	Christoph Hellwig <hch@infradead.org>,
	linux-kernel@vger.kernel.org, ltt-dev@shafik.org,
	"Martin J. Bligh" <mbligh@mbligh.org>,
	Douglas Niehaus <niehaus@eecs.ku.edu>,
	systemtap@sources.redhat.com,
	Thomas Gleixner <tglx@linutronix.de>,
	Richard J Moore <richardj_moore@uk.ibm.com>
Subject: [PATCH 2/2] lockdep reentrancy
Date: Tue, 16 Jan 2007 12:56:31 -0500	[thread overview]
Message-ID: <20070116175631.GB16084@Krystal> (raw)
In-Reply-To: <OFAB3D8A6C.1643F2D3-ON80257262.000581E4-80257262.00088F04@uk.ibm.com>

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 <mathieu.desnoyers@polymtl.ca>


@@ -1841,33 +1843,36 @@ void trace_hardirqs_on(void)
 	struct task_struct *curr = current;
 	unsigned long ip;
 
 	if (unlikely(!debug_locks || current->lockdep_recursion))
 		return;
 
+	current->lockdep_recursion++;
+	barrier();
+
 	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--;
 }
 
 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();
+	
 	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--;
 }
 
 EXPORT_SYMBOL(trace_hardirqs_off);

-- 
OpenPGP public key:              http://krystal.dyndns.org:8080/key/compudj.gpg
Key fingerprint:     8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68 

  parent reply	other threads:[~2007-01-16 17:56 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-12-20 23:52 [PATCH 0/4] Linux Kernel Markers Mathieu Desnoyers
2006-12-20 23:57 ` [PATCH 1/4] Linux Kernel Markers : Architecture agnostic code Mathieu Desnoyers
2006-12-20 23:59 ` [PATCH 2/4] Linux Kernel Markers : kconfig menus Mathieu Desnoyers
2006-12-21  0:00 ` [PATCH 3/4] Linux Kernel Markers : i386 optimisation Mathieu Desnoyers
2006-12-21  0:01 ` [PATCH 4/4] Linux Kernel Markers : powerpc optimisation Mathieu Desnoyers
2007-01-13  1:33 ` [PATCH 0/4] Linux Kernel Markers Richard J Moore
2007-01-13  5:45   ` Mathieu Desnoyers
2007-01-16 17:41     ` [PATCH 0/4 update] Linux Kernel Markers - i386 : pIII erratum 49 : XMC Mathieu Desnoyers
2007-01-16 18:35       ` Frank Ch. Eigler
2007-01-16 21:27       ` [PATCH 0/4 update] kprobes and traps Mathieu Desnoyers
2007-01-17 12:25         ` S. P. Prasanna
2007-01-16 17:56   ` [PATCH 1/2] lockdep missing barrier() Mathieu Desnoyers
2007-01-24  4:26     ` Andrew Morton
2007-01-24 16:51       ` Mathieu Desnoyers
2007-01-24 17:24         ` [PATCH] order of lockdep off/on in vprintk() should be changed Mathieu Desnoyers
2007-01-24 17:55           ` [PATCH] minimize lockdep_on/off side-effect Mathieu Desnoyers
2007-01-16 17:56   ` Mathieu Desnoyers [this message]
2007-01-24  4:29     ` [PATCH 2/2] lockdep reentrancy Andrew Morton
2007-01-24 16:55       ` Mathieu Desnoyers

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