From: Benny Halevy <bhalevy@panasas.com>
Subject: Re: block layout oops
Date: Thu, 30 Sep 2010 09:23:40 +0200
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References: <20100929172552.GA24460@merit.edu>
	<4CA3F1CE.2070108@cn.fujitsu.com>
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Cc: Jim Rees <rees@umich.edu>, linux-nfs@vger.kernel.org
To: Bian Naimeng <biannm@cn.fujitsu.com>
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2010/9/30 Bian Naimeng <biannm@cn.fujitsu.com>:
>> I'm getting this when I try to do a block layout mount with benny's =
new
>> pnfs-all-latest kernel, 2.6.36-rc6-pnfs:
>>
>> BUG: unable to handle kernel NULL pointer dereference at 00000008
>> IP: [<e0c5f9a3>] nfs4_proc_getdevicelist+0x3c/0x118 [nfs]
>> *pde =3D 00000000
>> Oops: 0000 [#1]
>> last sysfs file: /sys/module/sunrpc/initstate
>> Modules linked in: blocklayoutdriver nfs lockd fscache nfs_acl auth_=
rpcgss sunrpc ip6t_REJECT nf_conntrack_ipv6 ip6table_filter ip6_tables =
ipv6 iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi snd_intel8x0 =
snd_ac97_codec ac97_bus snd_pcm microcode snd_timer snd i2c_piix4 pcnet=
32 i2c_core soundcore pcspkr snd_page_alloc mii [last unloaded: speedst=
ep_lib]
>>
>> Pid: 1226, comm: mount.nfs4 Not tainted 2.6.36-rc6-pnfs #9 /VirtualB=
ox
>> EIP: 0060:[<e0c5f9a3>] EFLAGS: 00210246 CPU: 0
>> EIP is at nfs4_proc_getdevicelist+0x3c/0x118 [nfs]
>> EAX: 00000000 EBX: e0cb3310 ECX: 00000004 EDX: de9c3c40
>> ESI: df756000 EDI: de9c3c68 EBP: de9c3c90 ESP: de9c3c30
>> =A0DS: 007b ES: 007b FS: 0000 GS: 00e0 SS: 0069
>> Process mount.nfs4 (pid: 1226, ti=3Dde9c2000 task=3Ddf626380 task.ti=
=3Dde9c2000)
>> Stack:
>> =A0de9c3c40 de9c3c68 debfb300 dec0ee00 00000000 00000000 df756000 e0=
caec47
>> <0> c14b830c dea26588 dea26590 de9c3c88 c10a2f7f 00000008 00200246 e=
0cb3310
>> <0> c14b8624 de9c3c90 00000000 00000000 00000000 e0cb3310 00000003 d=
e9c3d38
>> Call Trace:
>> =A0[<e0caec47>] ? T.983+0x12/0x14 [blocklayoutdriver]
>> =A0[<c10a2f7f>] ? __kmalloc+0xf7/0x103
>> =A0[<e0caed2e>] ? bl_initialize_mountpoint+0xe5/0x36b [blocklayoutdr=
iver]
>> =A0[<e0c7233e>] ? set_pnfs_layoutdriver+0x146/0x1e2 [nfs]
>> =A0[<e0c48ba8>] ? nfs_probe_fsinfo+0x18a/0x2c0 [nfs]
>> =A0[<e0c483a6>] ? nfs_init_server_rpcclient+0x25/0xd1 [nfs]
>> =A0[<e0c49511>] ? nfs_clone_server+0x11f/0x206 [nfs]
>> =A0[<e0c51ca2>] ? nfs4_xdev_get_sb+0x42/0x1cc [nfs]
>> =A0[<c10acf0a>] ? vfs_kern_mount+0x9b/0x15d
>> =A0[<e0c59871>] ? nfs_follow_mountpoint+0x1df/0x31e [nfs]
>> =A0[<c10b3950>] ? do_follow_link+0xcc/0x1ed
>> =A0[<c10b3d54>] ? link_path_walk+0x2e3/0x3be
>> =A0[<c10b3f18>] ? path_walk+0x52/0xaf
>> =A0[<c10b3fe6>] ? vfs_path_lookup+0x71/0xb5
>> =A0[<e0c5197f>] ? nfs_follow_remote_path+0x126/0x255 [nfs]
>> =A0[<e0c51b9b>] ? nfs4_try_mount+0x61/0x94 [nfs]
>> =A0[<e0c52586>] ? nfs4_get_sb+0x22a/0x299 [nfs]
>> =A0[<c10acf0a>] ? vfs_kern_mount+0x9b/0x15d
>> =A0[<c10ad01b>] ? do_kern_mount+0x38/0xc2
>> =A0[<c10be1e9>] ? do_mount+0x5ee/0x634
>> =A0[<c10bcd5c>] ? copy_mount_options+0x78/0xd7
>> =A0[<c10be295>] ? sys_mount+0x66/0x94
>> =A0[<c132425c>] ? syscall_call+0x7/0xb
>> Code: c0 89 4d ac 8d 7d e8 b9 03 00 00 00 89 55 a8 8d 55 b0 f3 ab 8d=
 45 d8 89 45 a4 89 55 a0 8b 86 a8 01 00 00 b9 04 00 00 00 8b 7d a4 <8b>=
 50 08 31 c0 f3 ab 8b 4d a8 8b 7d a0 89 55 dc 89 4d d8 b9 06
>> EIP: [<e0c5f9a3>] nfs4_proc_getdevicelist+0x3c/0x118 [nfs] SS:ESP 00=
68:de9c3c30
>> CR2: 0000000000000008
>
>
> =A0Is this patch can fix it?
>
> ---------------------------------------------------------------------=
-
> We must specify the layout type before initialize mountpoint, so we s=
hould try set
> pnfs_curr_ld earlier.
>
> Signed-off-by: Bian Naimeng <biannm@cn.fujitsu.com>

patch looks good to me.

Benny

>
> ---
> =A0fs/nfs/pnfs.c | =A0 =A02 +-
> =A01 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
> index a225cd1..72ec712 100644
> --- a/fs/nfs/pnfs.c
> +++ b/fs/nfs/pnfs.c
> @@ -162,6 +162,7 @@ set_pnfs_layoutdriver(struct nfs_server *server, =
const struct nfs_fh *mntfh,
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0dprintk("%s: Could not grab reference =
on module\n", __func__);
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0goto out_no_driver;
> =A0 =A0 =A0 =A0}
> + =A0 =A0 =A0 server->pnfs_curr_ld =3D ld_type;
> =A0 =A0 =A0 =A0if (ld_type->initialize_mountpoint(server, mntfh)) {
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0printk(KERN_ERR
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 "%s: Error initializing m=
ount point for layout driver %u.\n",
> @@ -169,7 +170,6 @@ set_pnfs_layoutdriver(struct nfs_server *server, =
const struct nfs_fh *mntfh,
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0module_put(ld_type->owner);
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0goto out_no_driver;
> =A0 =A0 =A0 =A0}
> - =A0 =A0 =A0 server->pnfs_curr_ld =3D ld_type;
> =A0 =A0 =A0 =A0dprintk("%s: pNFS module for %u set\n", __func__, id);
> =A0 =A0 =A0 =A0return;
>
> --
> 1.7.0.1
>
>
>
>
> --
> Regards
> Bian Naimeng
>
> --
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