From 822191a2fa1584a29c3224ab328507adcaeac1ab Mon Sep 17 00:00:00 2001 From: Andrey Mirkin 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 Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/compat.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/compat.c b/fs/compat.c index 06dad665b88..7aef5412f49 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)) { -- 2.41.1