Kernel panic in is_our_io() function due to unsigned Kernel module involflt

Issue

• System crashes with following messages in the kernel ring buffer :

BUG: unable to handle kernel NULL pointer dereference at 0000000000000058
IP: [<ffffffffa007f874>] is_our_io+0x84/0x1b0 [involflt]
Kernel PGD 337d0e067 PUD 334cf8067 PMD 0 
User   PGD 337d0e067 PUD 334cf8067 PMD 0 
Oops: 0000 [#1] SMP 
last sysfs file: /sys/devices/system/cpu/online
CPU 0 
Modules linked in: autofs4 nfs lockd fscache auth_rpcgss nfs_acl sunrpc ipv6 vmware_balloon vmxnet3 sg shpchp i2c_piix4 ext3 jbd mbcache sd_mod crc_t10dif vmw_pvscsi pata_ac
pi ata_generic vmwgfx ttm drm_kms_helper drm i2c_core involflt(P)(U) dm_mirror dm_region_hash dm_log dm_mod [last unloaded: ip_tables]

Pid: 567, comm: kjournald Tainted: P           -- ------------    2.6.32-754.11.1.el6.x86_64 #1 VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform
RIP: 0010:[<ffffffffa007f874>]  [<ffffffffa007f874>] is_our_io+0x84/0x1b0 [involflt]
[..]
Stack:
 ffff88032e9c7b60 ffffffff812880b0 ffff88032e888e80 ffff88032e841e60
<d> ffff88032e9c7bf0 ffffffffa007fad8 ffff88032e9c0000 ffffffff81281d47
<d> ffff88032e9c7b90 ffff8803305c5c00 ffff8803305c5de0 ffff8803356cf240
Call Trace:
 [<ffffffff812880b0>] ? blk_queue_bio+0x0/0x5a0
 [<ffffffffa007fad8>] flt_make_request_fn+0x138/0x850 [involflt]
 [<ffffffff81281d47>] ? blk_unplug+0x37/0x70
 [<ffffffff81286755>] generic_make_request+0x245/0x5b0
 [<ffffffff81135d85>] ? mempool_alloc_slab+0x15/0x20
 [<ffffffff81559f8b>] ? __wait_on_bit_lock+0x7b/0xc0
 [<ffffffff81286b2e>] submit_bio+0x6e/0x120
 [<ffffffff811d7d4d>] submit_bh+0x11d/0x1f0
 [<ffffffffa02d7a5a>] journal_commit_transaction+0x43a/0x1310 [jbd]
 [<ffffffff8109327c>] ? lock_timer_base+0x3c/0x70
 [<ffffffff81093e9b>] ? try_to_del_timer_sync+0x7b/0xe0
 [<ffffffffa02dced5>] kjournald+0xe5/0x240 [jbd]
 [<ffffffff810aaeb0>] ? autoremove_wake_function+0x0/0x40
 [<ffffffffa02dcdf0>] ? kjournald+0x0/0x240 [jbd]
 [<ffffffff810aaa10>] kthread+0xa0/0xc0
 [<ffffffff815657bd>] child_rip+0xd/0x30
 [<ffffffff810aa970>] ? kthread+0x0/0xc0
 [<ffffffff815657b0>] ? child_rip+0x0/0x30
Code: 0f 84 a1 00 00 00 49 8b 04 24 48 8b 40 18 a8 01 0f 85 91 00 00 00 48 8b 15 f2 b4 04 00 48 83 ba 00 37 00 00 00 0f 84 ef 00 00 00 <4c> 8b 68 58 4d 85 ed 74 73 48 8b 3d d4 b4 04 00 48 81 c7 58 34 
RIP  [<ffffffffa007f874>] is_our_io+0x84/0x1b0 [involflt]
 RSP <ffff88032e9c7b40>
CR2: 0000000000000058