Re: [fuse-devel] Kernel panic on 2.6.27.9 when NFS exporting fuse filesystem

["J. Bruce Fields" <bfields@fieldses.org>]

On Tue, Jan 27, 2009 at 08:48:41PM +0100, Miklos Szeredi wrote:
> [Forwarding to linux-nfs@ and sunrpc maintainers]
> 
> On Mon, 26 Jan 2009, David Shaw wrote:
> > Hello,
> > 
> > This is reasonably repeatable (i.e. not 100%, but certainly more than
> > 25%).  The kernel is 2.6.27.9-159.fc10.i686.PAE (this is the most
> > recent Fedora 10 PAE kernel), and we're using fuse-2.8.0pre2 on the
> > userspace side.  We are NFS-exporting the fuse filesystem.  The
> > machine in question is a dual core Pentium D 2.8ghz with 4g of RAM.
> 
> Can you try to reproduce this on a vanilla kernel, to exclude the
> possibility of a fedora patch being the culprit?
> 
> > Occasionally, we get a sudden reboot.  After attaching a serial cable,
> > we found this.  It doesn't look directly fuse related from the
> > backtrace, but then again, we're not seeing any problems exporting a
> > regular (non-fuse) filesystem.
> > 
> > Any thoughts?
> 
> The BUG triggers in this __module_get() in svc_recv():
> 
> 			/*
> 			 * We know this module_get will succeed because the
> 			 * listener holds a reference too
> 			 */
> 			__module_get(newxpt->xpt_class->xcl_owner);
> 
> Either the comment is wrong or something got corrupted.
> 
> Tom, Bruce, any idea what could be causing this?  It doesn't really
> look fuse related.

I seem to recall something being fixed recently there--I'll try to find
the commit id.  In the mean time they might want to retest with the
latest kernel.

--b.

> 
> Thanks,
> Miklos
> 
> > 
> > kernel BUG at include/linux/module.h:390!
> > invalid opcode: 0000 [#1] SMP 
> > Modules linked in: nfsd lockd nfs_acl auth_rpcgss sunrpc exportfs ipt_REDIRECT fuse ipmi_devintf ipmi_si ipmi_msghandler ipv6 iptable_nat nf_nat dm_multipath tg3 i2c_i801 libphy i3000_edac iTCO_wdt iTCO_vendor_support edac_core serio_raw pcspkr dcdbas ata_generic pata_acpi radeon drm i2c_algo_bit i2c_core [last unloaded: scsi_wait_scan]
> > 
> > Pid: 25841, comm: nfsd Not tainted (2.6.27.9-159.fc10.i686.PAE #1)
> > EIP: 0060:[<f8b02cc4>] EFLAGS: 00010246 CPU: 0
> > EIP is at svc_recv+0x3a4/0x6c6 [sunrpc]
> > EAX: 00000000 EBX: f8b13500 ECX: f8b13500 EDX: 00001000
> > ESI: f78b7d90 EDI: f35ea600 EBP: f21c8fbc ESP: f21c8f74
> >  DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
> > Process nfsd (pid: 25841, ti=f21c8000 task=f4598000 task.ti=f21c8000)
> > Stack: c0893c80 0036ee80 f78b7000 f2549c04 f35ea61c f2549b80 f2549c00 f40a9600 
> >        f78b7000 f8bb1622 00000000 f4598000 c042d0f3 00100100 00200200 f3486b00 
> >        00000000 f78b7000 f21c8fd0 f8bb16e5 f78b7000 f8bb1622 00000000 f21c8fe0 
> > Call Trace:
> >  [<f8bb1622>] ? nfsd+0x0/0x167 [nfsd]
> >  [<c042d0f3>] ? default_wake_function+0x0/0xd
> >  [<f8bb16e5>] ? nfsd+0xc3/0x167 [nfsd]
> >  [<f8bb1622>] ? nfsd+0x0/0x167 [nfsd]
> >  [<c0443973>] ? kthread+0x3b/0x61
> >  [<c0443938>] ? kthread+0x0/0x61
> >  [<c04098f7>] ? kernel_thread_helper+0x7/0x10
> >  =======================
> > Code: 30 01 00 00 8b 57 04 89 f8 ff 52 04 85 c0 89 45 d4 0f 84 11 01 00 00 8b 00 8b 58 04 85 db 74 1f 89 d8 e8 56 d7 94 c7 85 c0 75 04 <0f> 0b eb fe 64 a1 04 c0 88 c0 c1 e0 07 ff 84 03 80 01 00 00 8b 
> > EIP: [<f8b02cc4>] svc_recv+0x3a4/0x6c6 [sunrpc] SS:ESP 0068:f21c8f74
> > Kernel panic - not syncing: Fatal exception
> > 
> > Thanks,
> > 
> > David
> > 
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