From: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Date: Mon, 21 Nov 2016 11:13:58 +0000 (+0100)
Subject: s390/vmlogrdr: fix IUCV buffer allocation
X-Git-Tag: v4.1.38~22
X-Git-Url: http://git.hungrycats.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f8c36e2b98b7b5ea41a01c60349f70764a4e33e6;p=linux

s390/vmlogrdr: fix IUCV buffer allocation

[ Upstream commit 5457e03de918f7a3e294eb9d26a608ab8a579976 ]

The buffer for iucv_message_receive() needs to be below 2 GB. In
__iucv_message_receive(), the buffer address is casted to an u32, which
would result in either memory corruption or an addressing exception when
using addresses >= 2 GB.

Fix this by using GFP_DMA for the buffer allocation.

Cc: stable@vger.kernel.org
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
---

diff --git a/drivers/s390/char/vmlogrdr.c b/drivers/s390/char/vmlogrdr.c
index 9bb48d70957c..4d20f7298cb8 100644
--- a/drivers/s390/char/vmlogrdr.c
+++ b/drivers/s390/char/vmlogrdr.c
@@ -872,7 +872,7 @@ static int __init vmlogrdr_init(void)
 		goto cleanup;
 
 	for (i=0; i < MAXMINOR; ++i ) {
-		sys_ser[i].buffer = (char *) get_zeroed_page(GFP_KERNEL);
+		sys_ser[i].buffer = (char *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
 		if (!sys_ser[i].buffer) {
 			rc = -ENOMEM;
 			break;