Re: [PATCH 0/3] dma-debug: add additional checks

[Peter Zijlstra]

On Wed, 2009-03-18 at 12:23 +0100, Ingo Molnar wrote:
> another -tip testbox started triggering:
> 
>   BUG: MAX_LOCKDEP_ENTRIES too low!
> 
> it triggers due to CONFIG_DMA_API_DEBUG=y. Config attached.


I still have this laying about.. could be we're just at the limit due to
lock bloat in the kernel, could be dma_api_debug is doing something
all-together iffy

Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
---
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 71b567f..3e1cc47 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -793,6 +793,7 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
 
 		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++;
@@ -856,6 +857,7 @@ static struct lock_list *alloc_list_entry(void)
 
 		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++;
@@ -1682,6 +1684,7 @@ cache_hit:
 
 		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++;
@@ -2524,6 +2527,7 @@ 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;
 	}
 
@@ -2620,6 +2624,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
 		debug_locks_off();
 		printk("BUG: MAX_LOCK_DEPTH too low!\n");
 		printk("turning off the locking correctness validator.\n");
+		dump_stack();
 		return 0;
 	}
 


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