From: Peter Zijlstra <peterz@infradead.org>
Date: Fri, 20 Mar 2009 10:13:20 +0000 (+0100)
Subject: lockdep: fix deadlock in lockdep_trace_alloc
X-Git-Url: http://www.pilppa.org/gitweb/gitweb.cgi?a=commitdiff_plain;h=2f8501815256af8498904e68bd0984b1afffd6f8;hp=19cefdffbfe0f7e280f21e80875937e8700e99e2;p=linux-2.6-omap-h63xx.git

lockdep: fix deadlock in lockdep_trace_alloc

Heiko reported that we grab the graph lock with irqs enabled.

Fix this by providng the same wrapper as all other lockdep entry
functions have.

Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Nick Piggin <npiggin@suse.de>
LKML-Reference: <1237544000.24626.52.camel@twins>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---

diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 022d2ed7fd8..3673a3f44d9 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -2260,7 +2260,7 @@ void trace_softirqs_off(unsigned long ip)
 		debug_atomic_inc(&redundant_softirqs_off);
 }
 
-void lockdep_trace_alloc(gfp_t gfp_mask)
+static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags)
 {
 	struct task_struct *curr = current;
 
@@ -2279,12 +2279,29 @@ void lockdep_trace_alloc(gfp_t gfp_mask)
 	if (!(gfp_mask & __GFP_FS))
 		return;
 
-	if (DEBUG_LOCKS_WARN_ON(irqs_disabled()))
+	if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags)))
 		return;
 
 	mark_held_locks(curr, RECLAIM_FS);
 }
 
+static void check_flags(unsigned long flags);
+
+void lockdep_trace_alloc(gfp_t gfp_mask)
+{
+	unsigned long flags;
+
+	if (unlikely(current->lockdep_recursion))
+		return;
+
+	raw_local_irq_save(flags);
+	check_flags(flags);
+	current->lockdep_recursion = 1;
+	__lockdep_trace_alloc(gfp_mask, flags);
+	current->lockdep_recursion = 0;
+	raw_local_irq_restore(flags);
+}
+
 static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock)
 {
 	/*