Tcmu populates the data area (used for communication with
userspace) with pages that are allocated by calling
alloc_page(GFP_NOIO).
Therefore previous content of the allocated pages is exposed
to user space. Avoid this by adding __GFP_ZERO flag.
Zeroing the pages does (nearly) not affect tcmu throughput,
because allocated pages are re-used for the data transfers of
later SCSI cmds.
Signed-off-by: Bodo Stroesser <bostroesser@xxxxxxxxx>
---
drivers/target/target_core_user.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c
index dc220fad06fa..a19e53877b0b 100644
--- a/drivers/target/target_core_user.c
+++ b/drivers/target/target_core_user.c
@@ -5,6 +5,7 @@
* Copyright (C) 2015 Arrikto, Inc.
* Copyright (C) 2017 Chinamobile, Inc.
*/
+#include <linux/delay.h>
#include <linux/spinlock.h>
#include <linux/module.h>
@@ -523,8 +524,8 @@ static inline int tcmu_get_empty_block(struct tcmu_dev *udev,
rcu_read_unlock();
for (i = cnt; i < page_cnt; i++) {
- /* try to get new page from the mm */
- page = alloc_page(GFP_NOIO);
+ /* try to get new zeroed page from the mm */
+ page = alloc_page(GFP_NOIO | __GFP_ZERO);
if (!page)
break;
--
2.12.3
