From: Zhao Hongjiang <zhaohongjiang@huawei.com>
Date: Fri, 26 Apr 2013 03:03:53 +0000 (+0800)
Subject: aio: fix possible invalid memory access when DEBUG is enabled
X-Git-Tag: v3.2.45~117
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=bf0f91c05b5abf5fafa0b1118db4c33fc011fcd1;p=people%2Fms%2Flinux.git

aio: fix possible invalid memory access when DEBUG is enabled

commit 91d80a84bbc8f28375cca7e65ec666577b4209ad upstream.

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

Signed-off-by: Zhao Hongjiang <zhaohongjiang@huawei.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2: keep the second argument to kunmap_atomic()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

diff --git a/fs/aio.c b/fs/aio.c
index 3b65ee767ce6..8cdd8ea0f44a 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1112,9 +1112,9 @@ static int aio_read_evt(struct kioctx *ioctx, struct io_event *ent)
 	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;
 }