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authorAndrey Mirkin <amirkin@openvz.org>2007-01-08 23:07:27 +0100
committerAdrian Bunk <bunk@stusta.de>2007-01-09 03:23:35 +0100
commitf701db35660a6017bef6d6e911d095bcf8b74010 (patch)
tree72396467093f251fd63990694c08208f96240419 /fs
parent80d0613d3f7076e5c478999f309d12d6ba46a220 (diff)
downloadlinux-linaro-stable-f701db35660a6017bef6d6e911d095bcf8b74010.tar.gz
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: [<ffffffff802bc7c6>] compat_sys_mount+0xd6/0x290 PGD 34d48067 PUD 34d03067 PMD 0 Oops: 0000 [1] SMP CPU: 0 Modules linked in: iptable_nat simfs smbfs ip_nat ip_conntrack vzdquota parport_pc lp parport 8021q bridge llc vznetdev vzmon nfs lockd sunrpc vzdev iptable_filter af_packet xt_length ipt_ttl xt_tcpmss ipt_TCPMSS iptable_mangle xt_limit ipt_tos ipt_REJECT ip_tables x_tables thermal processor fan button battery asus_acpi ac uhci_hcd ehci_hcd usbcore i2c_i801 i2c_core e100 mii floppy ide_cd cdrom Pid: 14656, comm: mount RIP: 0060:[<ffffffff802bc7c6>] [<ffffffff802bc7c6>] compat_sys_mount+0xd6/0x290 RSP: 0000:ffff810034d31f38 EFLAGS: 00010292 RAX: 000000000000002c RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff810034c86bc0 RSI: 0000000000000096 RDI: ffffffff8061fc90 RBP: ffff810034d31f78 R08: 0000000000000000 R09: 000000000000000d R10: ffff810034d31e58 R11: 0000000000000001 R12: ffff810039dc3000 R13: 000000000805ea48 R14: 0000000000000000 R15: 00000000c0ed0000 FS: 0000000000000000(0000) GS:ffffffff80749000(0033) knlGS:00000000b7d556b0 CS: 0060 DS: 007b ES: 007b CR0: 000000008005003b CR2: 0000000000000000 CR3: 0000000034d43000 CR4: 00000000000006e0 Process mount (pid: 14656, veid=300, threadinfo ffff810034d30000, task ffff810034c86bc0) Stack: 0000000000000000 ffff810034dd0000 ffff810034e4a000 000000000805ea48 0000000000000000 0000000000000000 0000000000000000 0000000000000000 000000000805ea48 ffffffff8021e64e 0000000000000000 0000000000000000 Call Trace: [<ffffffff8021e64e>] ia32_sysret+0x0/0xa Code: 83 3b 06 0f 85 41 01 00 00 0f b7 43 0c 89 43 14 0f b7 43 0a RIP [<ffffffff802bc7c6>] compat_sys_mount+0xd6/0x290 RSP <ffff810034d31f38> CR2: 0000000000000000 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> Signed-off-by: Adrian Bunk <bunk@stusta.de>
Diffstat (limited to 'fs')
-rw-r--r--fs/compat.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/compat.c b/fs/compat.c
index 8491bb8330f6..edc036104942 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -857,7 +857,7 @@ 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)) {