[RHEL5] Server rebooted because "kernel NULL pointer dereference at 0000000000000011 RIP: [<ffffffff80019e75>] do_sys_open+0x5c/0xbe"

Issue

• machine crash at do_sys_open on an openafs file.
• The task that panic'd was in an 'open' system call. The working directory of the process was an afs path. The backtrace was as follows:

    PID: 3182676  TASK: ffff816fd6d5b100  CPU: 59  COMMAND: "bmin"
     #3 [ffff816d67891ea0] error_exit at ffffffff8005dde9
        [exception RIP: do_sys_open+92]
        RIP: ffffffff80019e75  RSP: ffff816d67891f58  RFLAGS: 00010203
        RAX: 0000000000000001  RBX: 00000000000001b6  RCX: 0000000000000311
        RDX: ffff816d67891ea8  RSI: 0000000000000311  RDI: ffff81407ddc0e10
        RBP: 0000000000000001   R8: ffff816d67891bd8   R9: ffff817927a37e80
        R10: 0000000200000000  R11: ffff8160b02051d8  R12: 00000000ffffff9c
        R13: 000000000000000b  R14: ffff8170c2c1e000  R15: 0000000000000000
        ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
     #4 [ffff816d67891f80] tracesys at ffffffff8005d28d (via system_call)
        RIP: 00000036b10c58f0  RSP: 00007fffc7949118  RFLAGS: 00000246
        RAX: ffffffffffffffda  RBX: ffffffff8005d28d  RCX: ffffffffffffffff
        RDX: 00000000000001b6  RSI: 0000000000000241  RDI: 00007fffc79493d0
        RBP: 0000000000000000   R8: 0000000000000004   R9: 0000000000000001
        R10: 0000000000000241  R11: 0000000000000246  R12: 000000001a91f7e0
        R13: 00007fffc7949220  R14: 0000000000000004  R15: 000000001a91f7e0
        ORIG_RAX: 0000000000000002  CS: 0033  SS: 002b