Re: [PATCH] cifs: use standard token parser for mount options

[Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On Wed, 14 Mar 2012 14:17:26 -0400 (EDT)
Sachin Prabhu <sprabhu-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote:

> Thanks Scott,
> 
> Steve/Jeff, can I get your comments on this patch please.
> 
> Sachin Prabhu
> 

Does it address the oops that we saw with Scott's patch? Here's what I
wrote when I hit that oops before.

----------------------------[snip]---------------------------

Finally got around to trying this out and I get the following oops when
mounting a share with these options:

    sec=krb5i,multises,noauto

general protection fault: 0000 [#1] SMP 
last sysfs file: /sys/devices/virtual/bdi/cifs-1/uevent
CPU 0 
Modules linked in: cifs nfsd lockd nfs_acl exportfs rpcsec_gss_krb5 auth_rpcgss des_generic sunrpc ipv6 microcode i2c_piix4 i2c_core virtio_net joydev virtio_balloon virtio_blk virtio_pci virtio_ring virtio [last unloaded: mperf]

Pid: 1542, comm: mount.cifs Not tainted 2.6.35-0.2.rc3.git0.fc14.x86_64 #1 /
RIP: 0010:[<ffffffff8123728c>]  [<ffffffff8123728c>] strchr+0x14/0x1d
RSP: 0018:ffff880039a65bd8  EFLAGS: 00010246
RAX: 7365735f626d735f RBX: 0000000000000000 RCX: ffff88003cb4d041
RDX: ffff880039a65c6d RSI: 0000000000000025 RDI: 7365735f626d735f
RBP: ffff880039a65bd8 R08: 000000000000002c R09: 000000000000002c
R10: 00000000000080d0 R11: ffffffff8113bc6c R12: ffff88003cb4d041
R13: ffffffffa0219d40 R14: 0000000000000000 R15: 7365735f626d735f
FS:  00007f1fbcba6720(0000) GS:ffff880004600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000001a31818 CR3: 000000003a287000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process mount.cifs (pid: 1542, threadinfo ffff880039a64000, task ffff880039adc8a0)
Stack:
 ffff880039a65c48 ffffffff8123b1ee ffff88003a18b990 ffff880039a65cd8
<0> ffff88003cb4d041 ffffffff8111cd42 ffffffffa0202f86 7365735f626d735f
<0> ffff88003997de30 ffff88003997de30 ffff88003cc94840 00000000ffffffff
Call Trace:
 [<ffffffff8123b1ee>] match_token+0x4b/0x1a8
 [<ffffffff8111cd42>] ? __kmalloc+0x17c/0x18e
 [<ffffffffa0202f86>] ? cifs_mount+0x639/0x1737 [cifs]
 [<ffffffffa0202c11>] cifs_mount+0x2c4/0x1737 [cifs]
 [<ffffffffa01f5aa4>] ? cifs_get_sb+0x110/0x2e4 [cifs]
 [<ffffffffa01f5b00>] cifs_get_sb+0x16c/0x2e4 [cifs]
 [<ffffffff8112c946>] vfs_kern_mount+0xbd/0x19b
 [<ffffffff8112ca8c>] do_kern_mount+0x4d/0xed
 [<ffffffff8114368a>] do_mount+0x776/0x7ed
 [<ffffffff811128aa>] ? alloc_pages_current+0xa7/0xca
 [<ffffffff81143789>] sys_mount+0x88/0xc2
 [<ffffffff81009c32>] system_call_fastpath+0x16/0x1b
Code: 14 84 c0 74 0e 48 ff c7 48 ff c6 48 ff ca 48 85 d2 75 e1 31 c0 c9 c3 55 48 89 f8 48 89 e5 eb 0b 84 d2 75 04 31 c0 eb 0a 48 ff c0 <8a> 10 40 38 f2 75 ee c9 c3 55 48 89 f8 48 89 e5 eb 03 48 ff c0 
RIP  [<ffffffff8123728c>] strchr+0x14/0x1d
 RSP <ffff880039a65bd8>
---[ end trace 50d173d44b64b1d9 ]---

It's crashing in this match_token() call:

gdb) list *(cifs_mount+0x2c4)
0xdcf7 is in cifs_mount (fs/cifs/connect.c:1094).
1089		while ((data = strsep(&options, separator)) != NULL) {
1090			if (!*data)
1091				continue;
1092			if ((value = strchr(data, '=')) != NULL)
1093				*value++ = '\0';
1094			switch (match_token(data, cifs_mount_options, args)) {
1095			case Opt_user_xattr:
1096				vol->no_xattr = 0;
1097				break;
1098			case Opt_nouser_xattr:
(gdb) quit

-- 
Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>