[002/118] aio: fix possible invalid memory access when DEBUG isenabled

[Ben Hutchings]

3.2.45-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Zhao Hongjiang <zhaohongjiang@xxxxxxxxxx>

commit 91d80a84bbc8f28375cca7e65ec666577b4209ad upstream.

dprintk() shouldn't access @ring after it's unmapped.

Signed-off-by: Zhao Hongjiang <zhaohongjiang@xxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
[bwh: Backported to 3.2: keep the second argument to kunmap_atomic()]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 fs/aio.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1112,9 +1112,9 @@ static int aio_read_evt(struct kioctx *i
 	spin_unlock(&info->ring_lock);
 
 out:
-	kunmap_atomic(ring, KM_USER0);
 	dprintk("leaving aio_read_evt: %d  h%lu t%lu\n", ret,
 		 (unsigned long)ring->head, (unsigned long)ring->tail);
+	kunmap_atomic(ring, KM_USER0);
 	return ret;
 }
 

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