Kernel panic in nfs_flush_incompatible()

Issue

• Kernel panicked in nfs_flush_incompatible
• A system experienced a crash

• kernel panic with message:

      Unable to handle kernel NULL pointer dereference at 0000000000000020 RIP: 
       [<ffffffff884fd27a>] :nfs:nfs_flush_incompatible+0x6d/0xd1
      PGD 3bccd3067 PUD 2d87f5067 PMD 0 
      Oops: 0000 [1] SMP 
      last sysfs file: /devices/pci0000:00/0000:00:13.0/irq
      CPU 0 
      Modules linked in: vmmemctl(U) mvfs(U) autofs4 hidp nfs fscache nfs_acl rfcomm l2cap bluetooth lockd sunrpc deadman(U) dm_multipath scsi_dh video backlight sbs power_meter hwmon i2c_ec dell_wmi wmi button battery asus_acpi acpi_memhotplug ac ipv6 xfrm_nalgo crypto_api lp sg parport_pc i2c_piix4 ide_cd parport shpchp i2c_core cdrom floppy pcspkr serio_raw e1000 dm_raid45 dm_message dm_region_hash dm_mem_cache dm_snapshot dm_zero dm_mirror dm_log dm_mod cciss ata_piix libata mptspi mptscsih mptbase scsi_transport_spi sd_mod scsi_mod ext3 jbd uhci_hcd ohci_hcd ehci_hcd
      Pid: 26771, comm: find_closure Tainted: G      2.6.18-194.26.1.el5 #1
      RIP: 0010:[<ffffffff884fd27a>]  [<ffffffff884fd27a>] :nfs:nfs_flush_incompatible+0x6d/0xd1
      RSP: 0018:ffff81030e857b48  EFLAGS: 00010246
      RAX: 0000000000000000 RBX: ffff810178366640 RCX: 000000000000000b
      RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff81011227bba0
      RBP: 0000000000000000 R08: 0000000000000000 R09: ffff81030e857c80
      R10: ffff81030e857b28 R11: 0000000000000246 R12: ffff81010b30bcb8
      R13: ffff81011227bc40 R14: ffff81036e5a25c0 R15: 0000000000000000
      FS:  00002b841b64aaf0(0000) GS:ffffffff803ca000(0000) knlGS:0000000000000000
      CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
      CR2: 0000000000000020 CR3: 00000003a1480000 CR4: 00000000000006e0
      Process find_closure (pid: 26771, threadinfo ffff81030e856000, task ffff810161d2a820)
      Stack:  ffff81010b30bcb8 000000000000000b ffff81039b9b6d80 0000000000000000
       0000000000000cd7 ffffffff884f20b5 ffff81030e857c80 0000000b00000000
       ffff81011227bd50 ffffffff88512bc0 000000000000000b 0000000000000cd7
      Call Trace:
       [<ffffffff884f20b5>] :nfs:nfs_write_begin+0x65/0xf8
       [<ffffffff8000fd7a>] generic_file_buffered_write+0x14b/0x675
       [<ffffffff8001669e>] __generic_file_aio_write_nolock+0x369/0x3b6
       [<ffffffff80007691>] find_get_page+0x21/0x51
       [<ffffffff80021841>] generic_file_aio_write+0x65/0xc1
       [<ffffffff884f27b9>] :nfs:nfs_file_write+0xd8/0x14f
       [<ffffffff800182c3>] do_sync_write+0xc7/0x104
       [<ffffffff8009e4e4>] attach_pid+0x8c/0xb9
       [<ffffffff80066b88>] do_page_fault+0x4fe/0x874
       [<ffffffff800a0b16>] autoremove_wake_function+0x0/0x2e
       [<ffffffff80016aa6>] vfs_write+0xce/0x174
       [<ffffffff80017373>] sys_write+0x45/0x6e
       [<ffffffff8005d28d>] tracesys+0xd5/0xe0
  
  
      Code: 48 8b 50 20 65 48 8b 04 25 00 00 00 00 48 3b 90 98 05 00 00 
      RIP  [<ffffffff884fd27a>] :nfs:nfs_flush_incompatible+0x6d/0xd1
       RSP <ffff81030e857b48>