after rebooting into the new kernel our machine stops hard whenever someone logs in (which causes autofs to mount the user's homedir).

I worked around the problem by downgrading to NFS3, but this might want to be fixed

none of the x64 machines crashed (yet), so this problem might be confined to the i586 version.

Code:
Mar 26 06:28:31 login kernel: [  215.527565] BUG: unable to handle kernel NULL pointer dereference at 00000034
Mar 26 06:28:31 login kernel: [  215.528085] IP: [<f7f48afa>] nfs4_open_prepare+0x5a/0x160 [nfs]
Mar 26 06:28:31 login kernel: [  215.528774] *pdpt = 0000000034449001 *pde = 0000000000000000 
Mar 26 06:28:31 login kernel: [  215.528926] Oops: 0000 [#1] SMP 
Mar 26 06:28:31 login kernel: [  215.529190] Modules linked in: xt_pkttype ipt_LOG xt_limit autofs4 xt_tcpudp raw edd nfs lockd fscache auth_rpcgss nfs_acl sunrpc mperf vsock(X) acpiphp xt_NOTRACK ipt_REJECT xt_state iptable_raw iptable_filter nf_conntrack_ftp nf_conntrack_netbios_ns nf_conntrack_broadcast nf_conntrack_ipv4 nf_conntrack nf_defrag_ipv4 ip_tables ip6_tables x_tables fuse loop vmci(X) ppdev parport_pc ipv6_lib parport shpchp floppy intel_agp rtc_cmos vmw_balloon(X) pciehp pci_hotplug intel_gtt i2c_piix4 sr_mod i2c_core cdrom container button ac sg pcspkr ext3 jbd mbcache dm_mirror dm_region_hash dm_log linear processor thermal_sys hwmon sd_mod crc_t10dif scsi_dh_hp_sw scsi_dh_alua scsi_dh_emc scsi_dh_rdac scsi_dh dm_snapshot dm_mod vmw_pvscsi vmxnet3 ata_generic ata_piix libata scsi_mod
Mar 26 06:28:31 login kernel: [  215.529589] Supported: Yes, External
Mar 26 06:28:31 login kernel: [  215.529736] 
Mar 26 06:28:31 login kernel: [  215.529967] Pid: 11, comm: kworker/0:1 Tainted: G             X 3.0.101-0.47.50-pae #1 VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform
Mar 26 06:28:31 login kernel: [  215.530070] EIP: 0060:[<f7f48afa>] EFLAGS: 00010293 CPU: 0
Mar 26 06:28:31 login kernel: [  215.530130] EIP is at nfs4_open_prepare+0x5a/0x160 [nfs]
Mar 26 06:28:31 login kernel: [  215.530166] EAX: f3e083f8 EBX: f513d000 ECX: 00008001 EDX: 00000000
Mar 26 06:28:31 login kernel: [  215.530192] ESI: f50ffcc0 EDI: f6f83280 EBP: 00000000 ESP: f58e9f1c
Mar 26 06:28:31 login kernel: [  215.530222]  DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
Mar 26 06:28:31 login kernel: [  215.530276] Process kworker/0:1 (pid: 11, ti=f58e8000 task=f58e6e30 task.ti=f58e8000)
Mar 26 06:28:31 login kernel: [  215.530309] Stack:
Mar 26 06:28:31 login kernel: [  215.530369]  2d7e8263 00000032 f50ffcc0 f50ffd04 f50ffcf8 f7e23758 f7e242bc f619f100
Mar 26 06:28:31 login kernel: [  215.530485]  f619f100 2d7f135f 00000032 00000001 f58e6e30 f50ffd04 f58547c0 ff1e6c05
Mar 26 06:28:31 login kernel: [  215.530499]  f7e24477 00000000 c0266eec c0978e00 00000086 c025ded8 00000200 00000004
Mar 26 06:28:31 login kernel: [  215.530564] Call Trace:
Mar 26 06:28:31 login kernel: [  215.532031]  [<f7e23758>] rpc_prepare_task+0x8/0x10 [sunrpc]
Mar 26 06:28:31 login kernel: [  215.532113]  [<f7e242bc>] __rpc_execute+0x3c/0x1a0 [sunrpc]
Mar 26 06:28:31 login kernel: [  215.532140]  [<f7e24477>] rpc_async_schedule+0x17/0x20 [sunrpc]
Mar 26 06:28:31 login kernel: [  215.532404]  [<c0266eec>] process_one_work+0x13c/0x2e0
Mar 26 06:28:31 login kernel: [  215.532807]  [<c02697e7>] worker_thread+0x127/0x370
Mar 26 06:28:31 login kernel: [  215.532820]  [<c026d0e4>] kthread+0x74/0x80
Mar 26 06:28:31 login kernel: [  215.532832]  [<c05eb626>] kernel_thread_helper+0x6/0x10
Mar 26 06:28:31 login kernel: [  215.533100] Code: 00 00 85 c0 74 3c 8b 4b 0c 8b 53 10 e8 70 a5 ff ff 85 c0 0f 85 b0 00 00 00 8b 83 a4 02 00 00 83 7b 44 02 8b 40 1c 8b 50 dc 74 17 <8b> 42 34 a8 08 75 10 85 d2 8b 4b 10 74 09 89 c8 23 42 20 39 c1 
Mar 26 06:28:31 login kernel: [  215.533458] EIP: [<f7f48afa>] nfs4_open_prepare+0x5a/0x160 [nfs] SS:ESP 0068:f58e9f1c
Mar 26 06:28:31 login kernel: [  215.533543] CR2: 0000000000000034
Mar 26 06:28:31 login kernel: [  215.534040] ---[ end trace 1508d3f516225383 ]---
Mar 26 06:28:31 login kernel: [  215.534532] BUG: unable to handle kernel paging request at fffffffc
Mar 26 06:28:31 login kernel: [  215.534564] IP: [<c026cd06>] kthread_data+0x6/0x10
Mar 26 06:28:31 login kernel: [  215.534574] *pdpt = 0000000000927001 *pde = 0000000000ffb067 *pte = 0000000000000000 
Mar 26 06:28:31 login kernel: [  215.534619] Oops: 0000 [#2] SMP 
Mar 26 06:28:31 login kernel: [  215.534626] Modules linked in: xt_pkttype ipt_LOG xt_limit autofs4 xt_tcpudp raw edd nfs lockd fscache auth_rpcgss nfs_acl sunrpc mperf vsock(X) acpiphp xt_NOTRACK ipt_REJECT xt_state iptable_raw iptable_filter nf_conntrack_ftp nf_conntrack_netbios_ns nf_conntrack_broadcast nf_conntrack_ipv4 nf_conntrack nf_defrag_ipv4 ip_tables ip6_tables x_tables fuse loop vmci(X) ppdev parport_pc ipv6_lib parport shpchp floppy intel_agp rtc_cmos vmw_balloon(X) pciehp pci_hotplug intel_gtt i2c_piix4 sr_mod i2c_core cdrom container button ac sg pcspkr ext3 jbd mbcache dm_mirror dm_region_hash dm_log linear processor thermal_sys hwmon sd_mod crc_t10dif scsi_dh_hp_sw scsi_dh_alua scsi_dh_emc scsi_dh_rdac scsi_dh dm_snapshot dm_mod vmw_pvscsi vmxnet3 ata_generic ata_piix libata scsi_mod
Mar 26 06:28:31 login kernel: [  215.534737] Supported: Yes, External
Mar 26 06:28:31 login kernel: [  215.534742] 
Mar 26 06:28:31 login kernel: [  215.534749] Pid: 11, comm: kworker/0:1 Tainted: G      D      X 3.0.101-0.47.50-pae #1 VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform
Mar 26 06:28:31 login kernel: [  215.534764] EIP: 0060:[<c026cd06>] EFLAGS: 00010002 CPU: 0
Mar 26 06:28:31 login kernel: [  215.534771] EIP is at kthread_data+0x6/0x10
Mar 26 06:28:31 login kernel: [  215.534777] EAX: 00000000 EBX: 00000000 ECX: f58e6e30 EDX: 00000000
Mar 26 06:28:31 login kernel: [  215.534784] ESI: 00000000 EDI: f58e6e30 EBP: f58e9d54 ESP: f58e9cb4
Mar 26 06:28:31 login kernel: [  215.534791]  DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
Mar 26 06:28:31 login kernel: [  215.534797] Process kworker/0:1 (pid: 11, ti=f58e8000 task=f58e6e30 task.ti=f58e8000)
Mar 26 06:28:31 login kernel: [  215.534805] Stack:
Mar 26 06:28:31 login kernel: [  215.534809]  c0267e39 00000000 00000000 c05e20ae f6d5e084 f6c75d40 00000082 c0752e92
Mar 26 06:28:31 login kernel: [  215.534823]  00000088 00000000 f6d1a170 f6d7c800 f6d7c81c c0921100 c0921100 f58e6e30
Mar 26 06:28:31 login kernel: [  215.534837]  f619f100 f58e9d0f f6d5e084 f6d1a15c f6d65408 f6d1a154 f6d7c800 c03f5704
Mar 26 06:28:31 login kernel: [  215.534850] Call Trace:
Mar 26 06:28:31 login kernel: [  215.534861]  [<c0267e39>] wq_worker_sleeping+0x9/0x80
Mar 26 06:28:31 login kernel: [  215.534874]  [<c05e20ae>] __schedule+0x5ce/0x6d0
Mar 26 06:28:31 login kernel: [  215.534911]  [<c025292c>] do_exit+0x27c/0x400
Mar 26 06:28:31 login kernel: [  215.534926]  [<c05e58f3>] oops_end+0xc3/0xd0
Mar 26 06:28:31 login kernel: [  215.534936]  [<c022d6bd>] __bad_area_nosemaphore+0xed/0x170
Mar 26 06:28:31 login kernel: [  215.534987]  [<c022d74f>] bad_area_nosemaphore+0xf/0x20
Mar 26 06:28:31 login kernel: [  215.534997]  [<c05e792b>] do_page_fault+0x31b/0x470
Mar 26 06:28:31 login kernel: [  215.535006]  [<c05e4c3e>] error_code+0x5a/0x60
Mar 26 06:28:31 login kernel: [  215.535050]  [<f7f48afa>] nfs4_open_prepare+0x5a/0x160 [nfs]
Mar 26 06:28:31 login kernel: [  215.535105]  [<f7e23758>] rpc_prepare_task+0x8/0x10 [sunrpc]
Mar 26 06:28:31 login kernel: [  215.535130]  [<f7e242bc>] __rpc_execute+0x3c/0x1a0 [sunrpc]
Mar 26 06:28:31 login kernel: [  215.535155]  [<f7e24477>] rpc_async_schedule+0x17/0x20 [sunrpc]
Mar 26 06:28:31 login kernel: [  215.535174]  [<c0266eec>] process_one_work+0x13c/0x2e0
Mar 26 06:28:31 login kernel: [  215.535184]  [<c02697e7>] worker_thread+0x127/0x370
Mar 26 06:28:31 login kernel: [  215.535192]  [<c026d0e4>] kthread+0x74/0x80
Mar 26 06:28:31 login kernel: [  215.535200]  [<c05eb626>] kernel_thread_helper+0x6/0x10
Mar 26 06:28:31 login kernel: [  215.535207] Code: e8 60 3e 00 00 89 55 48 31 d2 89 45 44 e9 6d ff ff ff 66 90 90 64 a1 2c c5 91 c0 8b 80 7c 02 00 00 8b 40 f8 c3 8b 80 7c 02 00 00 <8b> 40 fc c3 8d b6 00 00 00 00 3b 05 60 a4 97 c0 74 08 64 a1 c0 
Mar 26 06:28:31 login kernel: [  215.535261] EIP: [<c026cd06>] kthread_data+0x6/0x10 SS:ESP 0068:f58e9cb4
Mar 26 06:28:31 login kernel: [  215.535271] CR2: 00000000fffffffc
Mar 26 06:28:31 login kernel: [  215.535279] ---[ end trace 1508d3f516225384 ]---
Mar 26 06:28:31 login kernel: [  215.535302] Fixing recursive fault but reboot is needed!