Server reported crash in vx_do_getattr() function provided by third party kernel module vxfs.

Issue

• System getting crashed with the following messages observed in the kernel buffer logs :

BUG: unable to handle kernel NULL pointer dereference at 0000000000000030
IP: [<ffffffffa0587476>] vx_do_getattr+0x496/0x750 [vxfs]
PGD 3f75aef067 PUD 3a61eda067 PMD 0 
Oops: 0000 [#1] SMP 
last sysfs file: /sys/devices/system/cpu/online
CPU 1 
[..]
Pid: 63779, comm: java Tainted: P           -- ------------    2.6.32-642.11.1.el6.x86_64 #1 IBM System x3850 X5 -[7143AC1]-/Node 1, Processor Card
RIP: 0010:[<ffffffffa0587476>]  [<ffffffffa0587476>] vx_do_getattr+0x496/0x750 [vxfs]
[..]
Call Trace:
 [<ffffffff810eb3fe>] ? __audit_inode+0x11e/0x350
 [<ffffffff811bc8a0>] ? mntput_no_expire+0x30/0x110
 [<ffffffffa058be16>] vx_getattr+0xc6/0x400 [vxfs]
 [<ffffffff811a7fe5>] ? putname+0x35/0x40
 [<ffffffff811ac542>] ? user_path_at+0x62/0xa0
 [<ffffffffa05e66b9>] vx_linux_getattr+0x79/0x1e0 [vxfs]
 [<ffffffff8119f861>] vfs_getattr+0x51/0x80
 [<ffffffff8119f6a4>] ? cp_new_stat+0xe4/0x100
 [<ffffffff8119f8f4>] vfs_fstatat+0x64/0xa0
 [<ffffffff8119fa5b>] vfs_stat+0x1b/0x20
 [<ffffffff8119fa84>] sys_newstat+0x24/0x50
 [<ffffffff810ee467>] ? audit_syscall_entry+0x1d7/0x200
 [<ffffffff810ee25e>] ? __audit_syscall_exit+0x25e/0x290
 [<ffffffff8100b0d2>] system_call_fastpath+0x16/0x1b
Code: 84 aa fd ff ff e9 88 fd ff ff 0f 1f 00 49 8b bf d0 01 00 00 48 81 c7 78 02 00 00 e8 f5 48 fc e0 48 8b 93 50 05 00 00 48 83 f8 ff <4c> 8b 6a 30 4c 8b 72 28 0f 85 4c 02 00 00 49 8b 87 d0 01 00 00 
RIP  [<ffffffffa0587476>] vx_do_getattr+0x496/0x750 [vxfs]
 RSP <ffff88240aa07ca8>