We modify the kmalloc_cache_dma[] array without proper locking.
Do the proper locking and undo the dma cache creation if another processor
has already created it.
Signed-off-by: Christoph Lameter <[EMAIL PROTECTED]>
---
mm/slub.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
Index: linux-2.6.22-rc4-mm2/mm/slub.c
===================================================================
--- linux-2.6.22-rc4-mm2.orig/mm/slub.c 2007-06-17 18:12:10.000000000 -0700
+++ linux-2.6.22-rc4-mm2/mm/slub.c 2007-06-17 18:12:13.000000000 -0700
@@ -2310,8 +2310,15 @@ static struct kmem_cache *dma_kmalloc_ca
text = kasprintf(flags & ~SLUB_DMA, "kmalloc_dma-%d",
(unsigned int)realsize);
s = create_kmalloc_cache(x, text, realsize, flags);
- kmalloc_caches_dma[index] = s;
- return s;
+ down_write(&slub_lock);
+ if (!kmalloc_caches_dma[index]) {
+ kmalloc_caches_dma[index] = s;
+ up_write(&slub_lock);
+ return s;
+ }
+ up_write(&slub_lock);
+ kmem_cache_destroy(s);
+ return kmalloc_caches_dma[index];
}
#endif
--
-
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