From: Amerigo Wang <amwang@redhat.com>
Date: Tue, 15 Dec 2009 09:38:44 -0500
Subject: [misc] lockdep: dump stack when hitting a limit
Message-id: <20091215094148.4709.20450.sendpatchset@localhost.localdomain>
Patchwork-id: 21936
O-Subject: [PATCH RHEL5.x] lockdep: dump stack when hitting a limit
Bugzilla: 546554
RH-Acked-by: Dean Nelson <dnelson@redhat.com>

BZ:
https://bugzilla.redhat.com/show_bug.cgi?id=546554

Description:
Dump the stack when we hit a lockdep limit, or
we don't know what was happening.

This is a straight backport of upstream commit
eedeeabd.

Signed-off-by: WANG Cong <amwang@redhat.com>


diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index b9b014c..2b63d9a 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -84,6 +84,7 @@ static struct lock_list *alloc_list_entry(void)
 		debug_locks_off();
 		printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n");
 		printk("turning off the locking correctness validator.\n");
+		dump_stack();
 		return NULL;
 	}
 	return list_entries + nr_list_entries++;
@@ -1444,6 +1445,7 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
 		debug_locks_off();
 		printk("BUG: MAX_LOCKDEP_KEYS too low!\n");
 		printk("turning off the locking correctness validator.\n");
+		dump_stack();
 		return NULL;
 	}
 	class = lock_classes + nr_lock_classes++;
@@ -1531,6 +1533,7 @@ cache_hit:
 		debug_locks_off();
 		printk("BUG: MAX_LOCKDEP_CHAINS too low!\n");
 		printk("turning off the locking correctness validator.\n");
+		dump_stack();
 		return 0;
 	}
 	chain = lock_chains + nr_lock_chains++;
@@ -2220,6 +2223,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
 		debug_locks_off();
 		printk("BUG: MAX_LOCKDEP_SUBCLASSES too low!\n");
 		printk("turning off the locking correctness validator.\n");
+		dump_stack();
 		return 0;
 	}
 
@@ -2414,6 +2418,7 @@ out_calc_hash:
 		debug_locks_off();
 		printk("BUG: MAX_LOCK_DEPTH too low!\n");
 		printk("turning off the locking correctness validator.\n");
+		dump_stack();
 		return 0;
 	}
 	if (unlikely(curr->lockdep_depth > max_lockdep_depth))