Re: nfs mount fail on linus 20090402 git

[Ingo Molnar <mingo@elte.hu>]

* Pekka Enberg <penberg@cs.helsinki.fi> wrote:

> On Fri, Apr 3, 2009 at 4:19 AM, Yinghai Lu <yinghai@kernel.org> wrote:
> > mpk12-3214-189-158:~ # cat x
> > mount -t nfs 10.6.75.100:/data/shared/pxeboot /x
> > mpk12-3214-189-158:~ # sh x
> > [   63.198629] ------------[ cut here ]------------
> > [   63.202589] kernel BUG at mm/slub.c:2753!
> > [   63.202589] invalid opcode: 0000 [#1] SMP
> > [   63.202589] last sysfs file: /sys/devices/virtual/net/sit0/type
> > [   63.202589] CPU 0
> > [   63.202589] Modules linked in:
> > [   63.202589] Pid: 10027, comm: mount.nfs Not tainted 2.6.29-07100-g833bb30 #21 Sun Fire X4440
> > [   63.202589] RIP: 0010:[<ffffffff802e0015>]  [<ffffffff802e0015>] kfree+0x5a/0xcd
> > [   63.202589] RSP: 0018:ffff882042ceb9f8  EFLAGS: 00010246
> > [   63.202589] RAX: 0200000000000000 RBX: 0000000000000005 RCX: ffffffff80a7dc1f
> > [   63.202589] RDX: ffffe20000000000 RSI: ffffc2000000f470 RDI: ffffe2001c018950
> > [   63.202589] RBP: ffff882042ceba18 R08: 0000000000000000 R09: ffffffff811019c0
> > [   63.202589] R10: 000000004262ce02 R11: ffff882042ceba18 R12: ffff880800706475
> > [   63.202589] R13: ffff882042886000 R14: ffff882042cebbd8 R15: ffff882042cebbf0
> > [   63.202589] FS:  00007fac729ed6f0(0000) GS:ffffc20000000000(0000) knlGS:0000000000000000
> > [   63.202589] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
> > [   63.202589] CR2: 00007fac72c12000 CR3: 0000001841cbb000 CR4: 00000000000006e0
> > [   63.202589] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > [   63.202589] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> > [   63.202589] Process mount.nfs (pid: 10027, threadinfo ffff882042cea000, task ffff8820434dc290)
> > [   63.202589] Stack:
> > [   63.202589]  ffff882042ceba18 000000004262ce02 0000000000000005 ffff882042886028
> > [   63.202589]  ffff882042ceba58 ffffffff80a7dc1f 000000004262ce02 ffff882042886000
> > [   63.202589]  000000004262ce02 ffff882042886000 ffffffff80a7b4a6 ffff882042c9ee18
> > [   63.202589] Call Trace:
> > [   63.202589]  [<ffffffff80a7dc1f>] xs_destroy+0x67/0xac
> > [   63.202589]  [<ffffffff80a7b4a6>] ? xprt_destroy+0x0/0xa7
> > [   63.202589]  [<ffffffff80a7b532>] xprt_destroy+0x8c/0xa7
> > [   63.202589]  [<ffffffff80a823b2>] ? put_rpccred+0x112/0x131
> > [   63.202589]  [<ffffffff8051cdd5>] kref_put+0x65/0x87
> > [   63.202589]  [<ffffffff80a7a9a9>] ? rpc_free_client+0x0/0xf9
> > [   63.202589]  [<ffffffff80a7b490>] xprt_put+0x23/0x39
> > [   63.202589]  [<ffffffff80a7aa7a>] rpc_free_client+0xd1/0xf9
> > [   63.202589]  [<ffffffff80a83345>] ? unx_destroy+0x3c/0x57
> > [   63.202589]  [<ffffffff8051cdd5>] kref_put+0x65/0x87
> > [   63.202589]  [<ffffffff80a7aaa2>] ? rpc_free_auth+0x0/0x69
> > [   63.202589]  [<ffffffff80a7aaf0>] rpc_free_auth+0x4e/0x69
> > [   63.202589]  [<ffffffff8025b827>] ? __wake_up+0x52/0x75
> > [   63.202589]  [<ffffffff8051cdd5>] kref_put+0x65/0x87
> > [   63.202589]  [<ffffffff80a7a98e>] rpc_release_client+0x64/0x7f
> > [   63.202589]  [<ffffffff80a8061c>] ? rpc_put_task+0xb0/0xcb
> > [   63.202589]  [<ffffffff80a7abe0>] rpc_shutdown_client+0xd5/0xf8
> > [   63.202589]  [<ffffffff80a7a893>] ? rpc_call_sync+0x63/0x80
> > [   63.202589]  [<ffffffff803fc4ab>] nfs_mount+0x11f/0x1bf
> > [   63.202589]  [<ffffffff803f3036>] nfs_get_sb+0x4ac/0x82a
> > [   63.202589]  [<ffffffff802e8f24>] vfs_kern_mount+0x61/0xbf
> > [   63.202589]  [<ffffffff802fea1d>] ? get_fs_type+0x58/0xc5
> > [   63.202589]  [<ffffffff802e9015>] do_kern_mount+0x56/0x108
> > [   63.202589]  [<ffffffff80302195>] do_mount+0x729/0x788
> > [   63.202589]  [<ffffffff80300025>] ? copy_mount_options+0xdf/0x155
> > [   63.202589]  [<ffffffff8030228c>] sys_mount+0x98/0xf8
> > [   63.202589]  [<ffffffff80230d6b>] system_call_fastpath+0x16/0x1b
> > [   63.202589] Code: 0c 48 ba 00 00 00 00 00 e2 ff ff 48 6b c0 38 48 8d 3c 10 48 8b 07 f6 c4 40 74 04 48 8b 7f 10 48 8b 07 84 c0 78 10 f6 c4 60 75 04 <0f> 0b eb fe e8 90 75 fd ff eb 4c 48 8b 4d 08 4c 8b 4f 10 9c 5b
> > [   63.202589] RIP  [<ffffffff802e0015>] kfree+0x5a/0xcd
> > [   63.202589]  RSP <ffff882042ceb9f8>
> > [   63.524555] ---[ end trace cd0d38e02ad11d61 ]---
> 
> Looks like a bogus pointer passed to kfree(). Lets cc some NFS folks.

a quick look suggests that this fresh commit moves around a kfree() 
and a destructor call:

  a67d18f: NFS: load the rpc/rdma transport module automatically

the commit log does not mention why the kfree was moved which 
suggests that it might have been done by mistake. (And it might be 
totally correct even - i have not checked the details.) I'll send a 
patch undoing those bits in the next mail.

	Ingo