Re: PROBLEM: kmem_cache_create: duplicate cache fat_cache

[Manfred Spraul]

OGAWA Hirofumi wrote:

> Ummm... why is this normal situation? Didn't you run the
> modules_install after changed .config?  Anyway, this patch returns
> NULL instead of calling BUG().  This case seems to also happen with
> user error.
>
>  
Either return NULL or ignore the collision. I don't know what's the 
better solution.

I'm open to either approach - it depends on what the kmem_cache_create() 
caller expects.

--
   Manfred
--- 2.6/mm/slab.c	2005-06-05 17:29:01.000000000 +0200
+++ build-2.6/mm/slab.c	2005-06-06 21:34:38.000000000 +0200
@@ -1480,9 +1480,14 @@
 			} 	
 			if (!strcmp(pc->name,name)) { 
 				printk("kmem_cache_create: duplicate cache %s\n",name); 
-				up(&cache_chain_sem); 
-				unlock_cpu_hotplug();
-				BUG(); 
+				/* This is a severe bug, because it breaks
+				 * tuning by writing to /proc/slabinfo.
+				 * But everything else works, and since
+				 * duplicate caches typically happen if
+				 * someone inserts a module twice, we'll
+				 * continue.
+				 */
+				WARN_ON(1); 
 			}	
 		}
 		set_fs(old_fs);