From 822191a2fa1584a29c3224ab328507adcaeac1ab Mon Sep 17 00:00:00 2001
From: Andrey Mirkin <amirkin@openvz.org>
Date: Wed, 6 Dec 2006 20:31:35 -0800
Subject: [PATCH] [PATCH] skip data conversion in compat_sys_mount when
data_page is NULL
OpenVZ Linux kernel team has found a problem with mounting in compat mode.
Simple command "mount -t smbfs ..." on Fedora Core 5 distro in 32-bit mode
leads to oops:
Unable to handle kernel NULL pointer dereference at 0000000000000000 RIP: compat_sys_mount+0xd6/0x290
Process mount (pid: 14656, veid=300, threadinfo ffff810034d30000, task ffff810034c86bc0)
Call Trace: ia32_sysret+0x0/0xa
The problem is that data_page pointer can be NULL, so we should skip data
conversion in this case.
Signed-off-by: Andrey Mirkin <amirkin@openvz.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
fs/compat.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/compat.c b/fs/compat.c
index 06dad665b88f..7aef5412f49c 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -871,7 +871,7 @@ asmlinkage long compat_sys_mount(char __user * dev_name, char __user * dir_name,
retval = -EINVAL;
- if (type_page) {
+ if (type_page && data_page) {
if (!strcmp((char *)type_page, SMBFS_NAME)) {
do_smb_super_data_conv((void *)data_page);
} else if (!strcmp((char *)type_page, NCPFS_NAME)) {