From: Frank van Maarseveen <frankvm@frankvm.com>
Subject: Re: 2.6.24.3 kernel BUG at fs/nfs/pagelist.c:82
Date: Thu, 20 Mar 2008 13:57:16 +0100
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References: <20080319094942.GA7627@janus> <1206017233.8465.7.camel@heimdal.trondhjem.org>
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Cc: linux-nfs@vger.kernel.org
To: Trond Myklebust <trond.myklebust@fys.uio.no>
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On Thu, Mar 20, 2008 at 08:47:13AM -0400, Trond Myklebust wrote:
> 
> On Wed, 2008-03-19 at 10:49 +0100, Frank van Maarseveen wrote:
> > FYI,
> > 
> > 2.6.24.3 wrote:
> > > kernel BUG at fs/nfs/pagelist.c:82!
> > 
> > BUG_ON(PagePrivate(page));
> > 
> > > invalid opcode: 0000 [#1] SMP 
> > > Modules linked in: vmnetfilter vmnet(P) vmmon(P) vmthrottle
> > 
> > In addition, there are some NFS patches for handling >16 groups and
> > selectively disabling attribute caching so its not a clean kernel.
> > 
> > > 
> > > Pid: 4575, comm: tail Tainted: P        (2.6.24.3-x177 #1)
                       ^^^^
> > > EIP: 0060:[<c01fc084>] EFLAGS: 00010202 CPU: 1
> > > EIP is at nfs_create_request+0xf4/0x100
> > > EAX: 80000821 EBX: e31a5300 ECX: 00000000 EDX: c1f0712c
> > > ESI: c1f0712c EDI: e31a5338 EBP: e56dfd90 ESP: e56dfd74
> > >  DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 
> > > Process tail (pid: 4575, ti=e56de000 task=d4b65500 task.ti=e56de000) 
> > > Stack: 00000000 f669ad20 cac3c168 e7330cb0 00000000 00000000 cac3c168 e56dfdc8 
> > >        c01fded5 00000000 000000a4 039cffff 000000a4 c1f0712c cac3c168 e7330cb0 
> > >        e56dfdb4 e56dfdb4 ffffff8c c1f0712c e7330cb0 e56dfdf0 c01fe8ce e56dfddc 
> > > Call Trace:
> > >  [<c010562a>] show_trace_log_lvl+0x1a/0x30
> > >  [<c01056fa>] show_stack_log_lvl+0x9a/0xc0
> > >  [<c01058a8>] show_registers+0xc8/0x1d0
> > >  [<c0105b1c>] die+0x10c/0x230
> > >  [<c0105cd1>] do_trap+0x91/0xd0  
> > >  [<c0105f79>] do_invalid_op+0x89/0xa0
> > >  [<c05bba02>] error_code+0x72/0x80
> > >  [<c01fded5>] nfs_readpage_async+0xb5/0x1b0
> > >  [<c01fe8ce>] nfs_readpage+0xae/0x120
> > >  [<c0155268>] do_generic_mapping_read+0xe8/0x440
> > >  [<c01558b0>] generic_file_aio_read+0x160/0x190
> > >  [<c01f4fb7>] nfs_file_read+0x97/0xe0
> > >  [<c01795e7>] do_sync_read+0xc7/0x120
> > >  [<c01796c4>] vfs_read+0x84/0x130
> > >  [<c01799fd>] sys_read+0x3d/0x70 
> > >  [<c0104292>] syscall_call+0x7/0xb
> > >  =======================
> > > Code: 02 75 0a e8 4f dc 3b 00 e9 4a ff ff ff 83 c4 10 b8 00 fe ff ff 5b 5e 5f 5d c3 8b 56 0c e9 7a ff ff ff 0f 0b eb fe 90 0f 0b eb fe <0f> 0b eb fe 90 8d b4 26 00 00 00 00 55 89 e5 53 83 ec 04 89 c3 
> > > EIP: [<c01fc084>] nfs_create_request+0xf4/0x100 SS:ESP 0068:e56dfd74
> > > ---[ end trace 0ef921372ea6410b ]--- 
> > 
> > The machine is a quad Xeon with 4GB ram with CONFIG_HIGHMEM64G=y
> 
> Would that be on a file that was open for read and write, or is it
> possible that some other process was writing to the same file? If so,
> then it might be a bug in nfs_wb_page().

Yes, I'm quite sure it was a "tail -f" on a logfile which gets
continuously appended to by another process.. So, one process reads it
while another one writes to it through different descriptors/struct file.

-- 
Frank