RHEL6 : oops on do_lookup as inode.i_ops contains nfs_mountpoint_inode_operations

Issue

RHEL6 system panic with this stack :

crash> bt
PID: 1139   TASK: ffff8808315f7520  CPU: 0   COMMAND: "mount.nfs4"
 #0 [ffff88082f73f6e0] machine_kexec at ffffffff810415ab
 #1 [ffff88082f73f740] crash_kexec at ffffffff810d6992
 #2 [ffff88082f73f810] oops_end at ffffffff8155e310
 #3 [ffff88082f73f840] no_context at ffffffff8105471b
 #4 [ffff88082f73f890] __bad_area_nosemaphore at ffffffff810549a5
 #5 [ffff88082f73f8e0] bad_area at ffffffff81054ace
 #6 [ffff88082f73f910] __do_page_fault at ffffffff810552ce
 #7 [ffff88082f73fa30] do_page_fault at ffffffff815602ce
 #8 [ffff88082f73fa60] page_fault at ffffffff8155d265
    [exception RIP: unknown or invalid address]
    RIP: 0000000000000000  RSP: ffff88082f73fb10  RFLAGS: 00010282
    RAX: 0000000000000000  RBX: ffff88082ce9b300  RCX: ffff8808165032c0
    RDX: ffff88082ce9b300  RSI: ffff88081187fa80  RDI: ffff880816503208
    RBP: ffff88082f73fb68   R8: ffff880816503208   R9: ffff88081187fa80
    R10: 0000000000000037  R11: 0000000000000000  R12: ffff88082f73fc08
    R13: ffff88082f73fbf8  R14: ffff88082d8f9180  R15: 000000000000000d
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
 #9 [ffff88082f73fb10] do_lookup at ffffffff811b1b1b
#10 [ffff88082f73fb70] __link_path_walk at ffffffff811b2156
#11 [ffff88082f73fc50] path_walk at ffffffff811b328a
#12 [ffff88082f73fc90] vfs_path_lookup at ffffffff811b33b3
#13 [ffff88082f73fce0] nfs_follow_remote_path at ffffffffa0435492 [nfs]
#14 [ffff88082f73fd40] nfs4_try_mount at ffffffffa04357af [nfs]
#15 [ffff88082f73fd80] nfs4_get_sb at ffffffffa04358b2 [nfs]
#16 [ffff88082f73fdd0] vfs_kern_mount at ffffffff811a4503
#17 [ffff88082f73fe20] do_kern_mount at ffffffff811a46a2
#18 [ffff88082f73fe70] do_mount at ffffffff811c6afb
#19 [ffff88082f73fef0] sys_mount at ffffffff811c71c0
#20 [ffff88082f73ff50] system_call_fastpath at ffffffff815643a7
    RIP: 00007f53c711d3da  RSP: 00007ffce0c60858  RFLAGS: 00010202
    RAX: 00000000000000a5  RBX: 00007ffce0c609a0  RCX: 00007ffce0c6092c
    RDX: 000055ce886c4436  RSI: 000055ce888ede70  RDI: 00007ffce0c618f1
    RBP: 000055ce888ee000   R8: 000055ce888ee190   R9: feff3733302d3636
    R10: 0000000000000000  R11: 0000000000000206  R12: 00007ffce0c609a0
    R13: 000055ce888edfc0  R14: 0000000000000010  R15: 00007ffce0c60930
    ORIG_RAX: 00000000000000a5  CS: 0033  SS: 002b