System panic at RIP get_block_start [d2dctl]

Issue

• System panic occurred in backup process with following log.

setup_bddev: D2D queue ra_pages: 32, orignal queue ra_pages: 32.
d2dctl_unlock_ioctl: Set bu queue depth: 4096, anticipatory queue depth: 3072, throughput: 120(M/min)
d2d_freeze_bdev: Lock device [MAJOR:MINOR=253:0], rw_attr=0
d2d_thaw_bdev: Unlock device [MAJOR:MINOR=253:0], rw_attr=0
setup_bddev: D2D queue ra_pages: 32, orignal queue ra_pages: 32.
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<ffffffffa04c7be9>] get_block_start+0x9/0x10 [d2dctl]
PGD 0 
Oops: 0000 [#1] SMP 
last sysfs file: /sys/devices/system/cpu/online
CPU 0 
Modules linked in: d2dctl(P)(U) bluetooth rfkill nfsd lockd nfs_acl auth_rpcgss exportfs autofs4 sunrpc cpufreq_ondemand freq_table pcc_cpufreq ipv6 ipt_REDIRECT iptable_nat nf_nat nf_conntrack_ipv4 nf_conntrack nf_defrag_ipv4 iptable_filter ip_tables microcode iTCO_wdt iTCO_vendor_support hpilo hpwdt osst st power_meter acpi_ipmi ipmi_si ipmi_msghandler tg3 ptp pps_core serio_raw sg lpc_ich mfd_core joydev shpchp ext4 jbd2 mbcache sd_mod crc_t10dif sr_mod cdrom hpsa qla2xxx scsi_transport_fc scsi_tgt pata_acpi ata_generic ata_piix dm_mirror dm_region_hash dm_log dm_mod [last unloaded: scsi_wait_scan]

Pid: 54949, comm: d2dagent Tainted: P           -- ------------    2.6.32-696.1.1.el6.x86_64 #1 HP ProLiant DL380p Gen8
RIP: 0010:[<ffffffffa04c7be9>]  [<ffffffffa04c7be9>] get_block_start+0x9/0x10 [d2dctl]
RSP: 0018:ffff8803cc467e88  EFLAGS: 00010246
RAX: ffff880b5c1df140 RBX: 0000000000000000 RCX: ffff8803cc467f48
RDX: 000000000000674f RSI: 00007f4037f9f900 RDI: 0000000000000000
RBP: ffff8803cc467e88 R08: ffffffffa04c2790 R09: 3a64656c69616620
R10: 64696c61766e4920 R11: 0000000000000246 R12: ffff880ac8cf71c0
R13: ffff8803cc467f48 R14: 00007f4037f9f900 R15: 0000000000000018
FS:  00007f4036d79720(0000) GS:ffff880061800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000000 CR3: 0000000d873ec000 CR4: 00000000001407f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process d2dagent (pid: 54949, threadinfo ffff8803cc464000, task ffff88018ba9eab0)
Stack:
 ffff8803cc467ed8 ffffffffa04c6398 0000000000000000 0000000000000000
<d> 0000000000000000 000000008123ac26 ffff882028056580 00007f4037f9f900
<d> ffff8803cc467f48 0000000000000000 ffff8803cc467ee8 ffffffffa04c27a5
Call Trace:
 [<ffffffffa04c6398>] core_read+0x248/0x420 [d2dctl]
 [<ffffffffa04c27a5>] d2dctl_read+0x15/0x20 [d2dctl]
 [<ffffffff8119a485>] vfs_read+0xb5/0x1a0
 [<ffffffff8119b236>] ? fget_light_pos+0x16/0x50
 [<ffffffff8119a7d1>] sys_read+0x51/0xb0
 [<ffffffff810ee3ce>] ? __audit_syscall_exit+0x25e/0x290
 [<ffffffff8100b0d2>] system_call_fastpath+0x16/0x1b
Code: 66 90 55 48 89 e5 0f 1f 44 00 00 48 8b 47 58 c9 c3 90 55 48 89 e5 0f 1f 44 00 00 48 89 77 58 c9 c3 90 55 48 89 e5 0f 1f 44 00 00 <48> 8b 07 c9 c3 66 90 55 48 89 e5 0f 1f 44 00 00 48 8b 47 10 c9 
RIP  [<ffffffffa04c7be9>] get_block_start+0x9/0x10 [d2dctl]
 RSP <ffff8803cc467e88>
CR2: 0000000000000000