Disk timeout error

[caj]

Hi ,

I have 5* bl460c g7 server with EVA6400 ,VC fabric with 2* 8/40 brocade switch.

Each VC has 2*8 GB link to each switch .And all the 4 port on the each controller is connected as per the standard .

OS RHEL 5u6

I am facing the below error when ever there is heavy I/O ,or some times (one try out of 10) simple multipath -ll or pvs will hung for some time and it throw the below error in the console/message file .Does any one having any idea what si gone wrong ?

Jan 19 03:15:54 testkernel: INFO: task mpath_prio_alua:23084 blocked for more than 120 seconds.
Jan 19 03:15:54 testkernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
Jan 19 03:15:54 testkernel: mpath_prio_al D ffffffff80153806 0 23084 8051 (NOTLB)
Jan 19 03:15:54 testkernel: ffff810f6b2f9a28 0000000000000086 ffff81080a6a2080 ffff81080bdbe4f8
Jan 19 03:15:54 testkernel: ffff81080bdbe000 0000000000000001 ffff810828250820 ffff81080b82e7a0
Jan 19 03:15:54 testkernel: 00005afd5ca08298 0000000000002cd3 ffff810828250a08 0000000f0a0b52c0
Jan 19 03:15:54 testkernel: Call Trace:
Jan 19 03:15:54 testkernel: [] wait_for_completion+0x79/0xa2
Jan 19 03:15:54 testkernel: [] default_wake_function+0x0/0xe
Jan 19 03:15:54 testkernel: [] blk_execute_rq_nowait+0x7e/0x92
Jan 19 03:15:54 testkernel: [] blk_execute_rq+0x98/0xc0
Jan 19 03:15:54 testkernel: [] sg_io+0x258/0x356
Jan 19 03:15:54 testkernel: [] scsi_cmd_ioctl+0x1d2/0x3b5
Jan 19 03:15:54 testkernel: [] avc_has_perm+0x46/0x58
Jan 19 03:15:54 testkernel: [] do_lookup+0x65/0x1e6
Jan 19 03:15:54 testkernel: [] :sd_mod:sd_ioctl+0x93/0xc2
Jan 19 03:15:54 testkernel: [] blkdev_driver_ioctl+0x5d/0x72
Jan 19 03:15:54 testkernel: [] blkdev_ioctl+0x63c/0x697
Jan 19 03:15:54 testkernel: [] avc_has_perm+0x46/0x58
Jan 19 03:15:54 testkernel: [] inode_has_perm+0x56/0x63
Jan 19 03:15:54 testkernel: [] blkdev_open+0x0/0x4f
Jan 19 03:15:54 testkernel: [] blkdev_open+0x23/0x4f
Jan 19 03:15:54 testkernel: [] __dentry_open+0x101/0x1dc
Jan 19 03:15:54 testkernel: [] block_ioctl+0x1b/0x1f
Jan 19 03:15:54 testkernel: [] do_ioctl+0x21/0x6b
Jan 19 03:15:54 testkernel: [] vfs_ioctl+0x457/0x4b9
Jan 19 03:15:54 testkernel: [] sys_ioctl+0x59/0x78
Jan 19 03:15:54 testkernel: [] tracesys+0xd5/0xe0
J

[caj]

can you please advise me on this error