Are there any news about this issue?.
After upgrading from ubuntu 10.04  to  ubuntu 12.04 precise, we are getting the same errors like it is described in this bug-report. We have an solaris nfs server and serveral Ubuntu box's as nfsv4 client. This worked fine with 10.04, with 12.04  we are getting these errors:


[  308.555535] NFS: nfs4_reclaim_open_state: Lock reclaim failed!
 [  309.139900] nfs4_reclaim_open_state: unhandled error -10026. Zeroing state
 [  309.140185] nfs4_reclaim_open_state: unhandled error -10026. Zeroing state
 [  309.882763] NFS: v4 server returned a bad sequence-id error on an unconfirmed sequence ec5be010!
 [  311.029716] BUG: unable to handle kernel NULL pointer dereference at 000000a4
 [  311.029800] IP: [<xxxxxxxx>] nfs4_alloc_lockdata+0x1c/0x1c0 [nfs]
 [  311.029882] *pdpt = 000000002ce7f001 *pde = 0000000000000000
 [  311.029951] Oops: 0000 [#1] SMP
 [  311.029980] Modules linked in: autofs4 rfcomm bnep bluetooth parport_pc ppdev binfmt_misc nfsd nfs lockd fscache auth_rpcgss nfs_acl sunrpc joydev snd_hda_codec_realtek snd_hda_intel snd_hda_codec radeon snd_hwdep snd_pcm snd_seq_midi snd_rawmidi snd_seq_midi_event psmouse snd_seq snd_timer serio_raw snd_seq_device ttm hid_logitech_dj drm_kms_helper drm snd soundcore snd_page_alloc i2c_algo_bit mac_hid mei(C) lp parport usbhid hid e1000e
 [  311.030353]
 [  311.030367] Pid: 3312, comm: xxx.yyy.zzz.ff- Tainted: G         C   3.2.0-24-generic-pae #37-Ubuntu 
 [  311.030475] EIP: 0060:[<f88c0b6c>] EFLAGS: 00010282 CPU: 1
 [  311.030525] EIP is at nfs4_alloc_lockdata+0x1c/0x1c0 [nfs]
 [  311.030563] EAX: 00000088 EBX: f39b69a0 ECX: ec5be700 EDX: 00000050
 [  311.030611] ESI: ec5be700 EDI: 00000006 EBP: ec75be88 ESP: ec75be70
 [  311.030658]  DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
 [  311.030700] Process xxx.yyy.zzz.ff- (pid: 3312, ti=ec75a000 task=ec45d860 task.ti=ec75a000)
 [  311.030761] Stack:
 [  311.030781]  ec692e80 f39b69a0 ed839480 f39b69a0 00000002 00000006 ec75bed4 f88c0daa
 [  311.030853]  00000050 f7402580 ec75bec8 00000000 f39b1b00 ec75beb8 f88d2898 00000000
 [  311.030930]  edab8f60 00000001 f88dbeb8 00000000 00000000 ed839480 ee192c80 f39b69a0
 [  311.031009] Call Trace:
 [  311.031041]  [<f88c0daa>] _nfs4_do_setlk.isra.37+0x9a/0x1f0 [nfs]
 [  311.031096]  [<f88c12ba>] nfs4_lock_expired+0x6a/0xb0 [nfs]
 [  311.031148]  [<f88c9ab6>] nfs4_reclaim_locks.isra.17+0x86/0x140 [nfs]
 [  311.031200]  [<f88a82af>] ? put_nfs_open_context+0xf/0x20 [nfs]
 [  311.031253]  [<f88ca85a>] nfs4_reclaim_open_state+0x8a/0x280 [nfs]
 [  311.031308]  [<f88cab10>] nfs4_do_reclaim+0xc0/0x100 [nfs]
 [  311.031367]  [<f88cad00>] nfs4_state_manager+0x1b0/0x2a0 [nfs]
 [  311.031417]  [<c106b817>] ? recalc_sigpending+0x17/0x40
 [  311.031470]  [<f88cadf0>] ? nfs4_state_manager+0x2a0/0x2a0 [nfs]
 [  311.031530]  [<f88cae0c>] nfs4_run_state_manager+0x1c/0x30 [nfs]
 [  311.031573]  [<c107956d>] kthread+0x6d/0x80
 [  311.031609]  [<c1079500>] ? flush_kthread_worker+0x80/0x80
 [  311.031655]  [<c15af6be>] kernel_thread_helper+0x6/0x10
 [  311.031693] Code: c7 04 24 e6 4f 8d f8 e8 b8 1b cd c8 eb a8 90 55 89 e5 57 56 53 83 ec 0c 3e 8d 74 26 00 89 45 ec 8b 41 08 89 ce 89 55 e8 8b 55 08 <8b> 78 1c 80 ce 80 f6 c2 01 8b 47 1c 8b 80 d0 01 00 00 89 45 f0
 [  311.031990] EIP: [<f88c0b6c>] nfs4_alloc_lockdata+0x1c/0x1c0 [nfs] SS:ESP 0068:ec75be70
 [  311.032061] CR2: 00000000000000a4
 [  311.044208] ---[ end trace ff67295de72dfb75 ]---