[linux-cifs-client] DFS fails to follow remote links

Mon Nov 17 18:51:05 GMT 2008

On Mon, 17 Nov 2008 21:07:48 +0530
Suresh Jayaraman <sjayaraman at suse.de> wrote:

> Trying to get cifs DFS working..
> 
> 2 Windows 2003R2 servers:
> 
> Server1: DFS namespace server, standalone, no AD integration with dfs namespace 'ns1'. Namespace ns1 contains dfs folder folder_on_2 which is dfs link to shared folder 'shared' on server2.
> 
> Server2: contains share folder 'shared' which is accessible via DFS from server1
> 
> All addressing is done with ip addresses to make sure problem is not
> netbios/wins related.
> 
> mount -t cifs -ouser=Administrator,domain=DFSST \\\\server1\\ns1 /mnt
> 
> "ls /mnt" works fine
> 
> Trying to access 'folder_on_2' gives the error:
> ls /mnt/folder_on_2
> ls: reading directory /mnt/folder_on_2: Object is remote
> 
> If I try ls again, I get the following oops:
> 
> ---
> Oct 22 16:37:34 linux-kocf kernel: BUG: unable to handle kernel NULL pointer dereference at 0000000000000004
> Oct 22 16:37:34 linux-kocf kernel: IP: [<ffffffff803206a4>] call_sbin_request_key+0x16d/0x28d
> Oct 22 16:37:34 linux-kocf kernel: PGD 88c7067 PUD 41a6067 PMD 0 
> Oct 22 16:37:34 linux-kocf kernel: Oops: 0000 [1] SMP linux-cifs-client at lists.samba.org
> Oct 22 16:37:34 linux-kocf kernel: last sysfs file: /sys/devices/pci0000:00/0000:00:11.0/net/eth0/statistics/collisions
> Oct 22 16:37:34 linux-kocf kernel: CPU 0 
> Oct 22 16:37:34 linux-kocf kernel: Modules linked in: cifs(X) nls_utf8 ipv6 af_packet microcode fuse loop dm_mod ppdev rtc_cmos rtc_core rtc_lib parport_pc parport pcspkr sg container sr_mod cdrom ac button e1000 i2c_piix4 shpchp intel_agp pci_hotplug i2c_core sd_mod crc_t10dif edd ext3 mbcache jbd fan ide_pci_generic pata_acpi ata_generic piix ide_core mptspi mptscsih mptbase scsi_transport_spi ata_piix libata scsi_mod dock thermal processor thermal_sys hwmon
> Oct 22 16:37:34 linux-kocf kernel: Supported: Yes, External
> Oct 22 16:37:34 linux-kocf kernel: Pid: 3757, comm: ls Tainted: G        W 2.6.27.1-2-default #1
> Oct 22 16:37:34 linux-kocf kernel: RIP: 0010:[<ffffffff803206a4>]  [<ffffffff803206a4>] call_sbin_request_key+0x16d/0x28d
> Oct 22 16:37:34 linux-kocf kernel: RSP: 0018:ffff8800088db9a8  EFLAGS: 00010246
> Oct 22 16:37:34 linux-kocf kernel: RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
> Oct 22 16:37:34 linux-kocf kernel: RDX: 00000000fffffffb RSI: 0000000000000000 RDI: 00000000ffffffff
> Oct 22 16:37:34 linux-kocf kernel: RBP: ffff8800041a2300 R08: 00000000ffffffff R09: 0000000000000000
> Oct 22 16:37:34 linux-kocf kernel: R10: 000000000000000a R11: 0000000000018600 R12: ffff8800040c1a40
> Oct 22 16:37:34 linux-kocf kernel: R13: ffff8800088dba14 R14: ffff8800040c1bc0 R15: ffff880004107e00
> Oct 22 16:37:34 linux-kocf kernel: FS:  00007faf38936780(0000) GS:ffffffff80844a00(0000) knlGS:0000000000000000
> Oct 22 16:37:34 linux-kocf kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
> Oct 22 16:37:34 linux-kocf kernel: CR2: 0000000000000004 CR3: 0000000013cce000 CR4: 00000000000006e0
> Oct 22 16:37:34 linux-kocf kernel: DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> Oct 22 16:37:34 linux-kocf kernel: DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 000cifs dfs requires keyutils package to work properly. Could you check whether
> these packages are installed0000000000400
> Oct 22 16:37:34 linux-kocf kernel: Process ls (pid: 3757, threadinfo ffff8800088da000, task ffff8800041a2300)
> Oct 22 16:37:34 linux-kocf kernel: Stack:  00000000000000d0 ffffffff805cedf5 0000000000000000 0000000000000000
> Oct 22 16:37:34 linux-kocf kernel:  0000000000000000 ffffffff804a0452 ffff8800040c1b00 ffff8800040c1b04
> Oct 22 16:37:34 linux-kocf kernel:  ffff8800040c1b00 ffffffff8031ccf6 ffff8800088dba98 0000000000000000
> Oct 22 16:37:34 linux-kocf kernel: Call Trace:
> Oct 22 16:37:34 linux-kocf kernel:  [<ffffffff803202f0>] construct_key+0xa1/0xd4
> Oct 22 16:37:34 linux-kocf kernel:  [<ffffffff803203e1>] request_key_and_link+0xbe/0xfa
> Oct 22 16:37:34 linux-kocf kernel:  [<ffffffff803204c8>] request_key+0x37/0x67
> Oct 22 16:37:34 linux-kocf kernel:  [<ffffffffa0334845>] dns_resolve_server_name_to_ip+0x22d/0x250 [cifs]
> Oct 22 16:37:34 linux-kocf kernel:  [<ffffffffa033499d>] compose_mount_options+0x4c/0x248 [cifs]
> Oct 22 16:37:34 linux-kocf kernel:  [<ffffffffa0334de1>] cifs_dfs_follow_mountpoint+0x216/0x412 [cifs]
> Oct 22 16:37:34 linux-kocf kernel:  [<ffffffff802c3342>] __link_path_walk+0xaee/0xe0b
> Oct 22 16:37:34 linux-kocf kernel:  [<ffffffff802c382a>] path_walk+0x5e/0xb9
> Oct 22 16:37:34 linux-kocf kernel:  [<ffffffff802c39e7>] do_path_lookup+0x162/0x1b9
> Oct 22 16:37:34 linux-kocf kernel:  [<ffffffff802c4380>] user_path_at+0x48/0x79
> Oct 22 16:37:34 linux-kocf kernel:  [<ffffffff802bcd99>] vfs_stat_fd+0x18/0x44
> Oct 22 16:37:34 linux-kocf kernel:  [<ffffffff802bce21>] sys_newstat+0x19/0x31
> Oct 22 16:37:34 linux-kocf kernel:  [<ffffffff8020c37a>] system_call_fastpath+0x16/0x1b
> Oct 22 16:37:34 linux-kocf kernel:  [<00007faf37e73af5>] 0x7faf37e73af5
> Oct 22 16:37:34 linux-kocf kernel: 
> Oct 22 16:37:34 linux-kocf kernel: 
> Oct 22 16:37:34 linux-kocf kernel: Code: ef e8 c3 8e 04 00 48 8b 85 68 05 00 00 48 83 b8 30 03 00 00 00 74 09 48 8b 80 30 03 00 00 eb 0b 48 8b 85 48 04 00 00 48 8b 40 30 <8b> 50 04 48 8d 5c 24 78 48 c7 c6 0b 6cifs dfs requires keyutils package to work properly. Could you check whether
> these packages are installed6 5c 80 31 c0 48 89 df e8 
> Oct 22 16:37:34 linux-kocf kernel: RIP  [<ffffffff803206a4>] call_sbin_request_key+0x16d/0x28d
> Oct 22 16:37:34 linux-kocf kernel:  RSP <ffff8800088db9a8>
> Oct 22 16:37:34 linux-kocf kernel: CR2: 0000000000000004
> Oct 22 16:37:34 linux-kocf kernel: ---[ end trace 4eaa2a86a8e2da22 ]---
> ---
> 
> kernel version - 2.6.27.1
> Pkgs keyutils, keyutils-libs installed
> and /etc/request.conf configured like below:
> 
> create      cifs.spnego    * * /usr/sbin/cifs.upcall -c %k
> create      dns_resolver   * * /usr/sbin/cifs.upcall %k
> 
> Is this a known issue or am I missing something in the configuration?
> Any clues?
> 

Known bug, I think. You need this patch from David Howells:

Subject: [PATCH] KEYS: Make request key instantiate the per-user keyrings

...I think it's in mainline now.

-- 
Jeff Layton <jlayton at redhat.com>