linux-kernel - [PATCH 1/2] Revert "staging: zcache: cleanup zcache_do_preload and zcache_put

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Date:	Thu, 23 Aug 2012 10:33:10 -0500
From:	Seth Jennings <sjenning@...ux.vnet.ibm.com>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:	Seth Jennings <sjenning@...ux.vnet.ibm.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Nitin Gupta <ngupta@...are.org>,
	Minchan Kim <minchan@...nel.org>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	Dan Magenheimer <dan.magenheimer@...cle.com>,
	linux-mm@...ck.org, linux-kernel@...r.kernel.org,
	devel@...verdev.osuosl.org
Subject: [PATCH 1/2] Revert "staging: zcache: cleanup zcache_do_preload and zcache_put_page"

This reverts commit b71f3bcc5ab5e76a22d7ad82b3795602fcf0e0af.

This commit is resulting  memory corruption in the cleancache case

Signed-off-by: Seth Jennings <sjenning@...ux.vnet.ibm.com>
Reported-by: Dan Magenheimer <dan.magenheimer@...cle.com>
---
 drivers/staging/zcache/zcache-main.c |   37 +++++++++++++++++++---------------
 1 file changed, 21 insertions(+), 16 deletions(-)

diff --git a/drivers/staging/zcache/zcache-main.c b/drivers/staging/zcache/zcache-main.c
index c214977..8a335b9 100644
--- a/drivers/staging/zcache/zcache-main.c
+++ b/drivers/staging/zcache/zcache-main.c
@@ -1048,24 +1048,29 @@ static int zcache_do_preload(struct tmem_pool *pool)
 		kp->objnodes[kp->nr++] = objnode;
 	}
 
-	if (!kp->obj) {
-		obj = kmem_cache_alloc(zcache_obj_cache, ZCACHE_GFP_MASK);
-		if (unlikely(obj == NULL)) {
-			zcache_failed_alloc++;
-			goto out;
-		}
-		kp->obj = obj;
+	obj = kmem_cache_alloc(zcache_obj_cache, ZCACHE_GFP_MASK);
+	if (unlikely(obj == NULL)) {
+		zcache_failed_alloc++;
+		goto out;
 	}
 
-	if (!kp->page) {
-		page = (void *)__get_free_page(ZCACHE_GFP_MASK);
-		if (unlikely(page == NULL)) {
-			zcache_failed_get_free_pages++;
-			goto out;
-		}
-		kp->page =  page;
+	page = (void *)__get_free_page(ZCACHE_GFP_MASK);
+	if (unlikely(page == NULL)) {
+		zcache_failed_get_free_pages++;
+		kmem_cache_free(zcache_obj_cache, obj);
+		goto out;
 	}
 
+	if (kp->obj == NULL)
+		kp->obj = obj;
+	else
+		kmem_cache_free(zcache_obj_cache, obj);
+
+	if (kp->page == NULL)
+		kp->page = page;
+	else
+		free_page((unsigned long)page);
+
 	ret = 0;
 out:
 	return ret;
@@ -1575,14 +1580,14 @@ static int zcache_put_page(int cli_id, int pool_id, struct tmem_oid *oidp,
 			else
 				zcache_failed_pers_puts++;
 		}
+		zcache_put_pool(pool);
 	} else {
 		zcache_put_to_flush++;
 		if (atomic_read(&pool->obj_count) > 0)
 			/* the put fails whether the flush succeeds or not */
 			(void)tmem_flush_page(pool, oidp, index);
+		zcache_put_pool(pool);
 	}
-
-	zcache_put_pool(pool);
 out:
 	return ret;
 }
-- 
1.7.9.5

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