[PATCH] vhost: zero vhost_vsock memory on allocation

From: Vitaly Mayatskikh
Date: Tue Mar 26 2019 - 20:56:34 EST


This fixes OOPS when using under-initialized vhost_vsock object.

The code had a combo of kzalloc plus vmalloc as a fallback
initially, but it has been replaced by plain kvmalloc in
commit 6c5ab6511f71 ("mm: support __GFP_REPEAT in kvmalloc_node for >32kB")

OOPS is easy to reproduce with open/ioctl after trashing the RAM.

Signed-off-by: Vitaly Mayatskikh <v.mayatskih@xxxxxxxxx>
---
drivers/vhost/vsock.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index bb5fc0e..9e7cb13 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -512,7 +512,7 @@ static int vhost_vsock_dev_open(struct inode *inode, struct file *file)
/* This struct is large and allocation could fail, fall back to vmalloc
* if there is no other way.
*/
- vsock = kvmalloc(sizeof(*vsock), GFP_KERNEL | __GFP_RETRY_MAYFAIL);
+ vsock = kvzalloc(sizeof(*vsock), GFP_KERNEL | __GFP_RETRY_MAYFAIL);
if (!vsock)
return -ENOMEM;

--
1.8.3.1