lockdep: fix deadlock in lockdep_trace_alloc
Peter Zijlstra [Fri, 20 Mar 2009 10:13:20 +0000 (11:13 +0100)]
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>

kernel/lockdep.c

index 022d2ed..3673a3f 100644 (file)
@@ -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)
 {
        /*