Bug 688334

---Problem Description---
Kdump kernel hangs while loading megaraid_sas.

---Serial console fragment--- 
Loading megaraid_sas.ko module
megasas: INIT adapter done
DRHD: handling fault status reg 502
INTR-REMAP: Request device [[04:00.0] fault index 44
INTR-REMAP:[fault reason 34] Present field in the IRTE entry is clear
DRHD: handling fault status reg 602
INTR-REMAP: Request device [[04:00.0] fault index 45
INTR-REMAP:[fault reason 34] Present field in the IRTE entry is clear
INFO: task insmod:259 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
INFO: task insmod:259 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.

#####after this the kdump kernel hangs.

---uname output---
Linux mx3850x5.xx.xxx.xxx 2.6.32-118.el6.x86_64 #1 SMP Tue Feb 22 11:15:55 EST 2011 x86_64 x86_64
x86_64 GNU/Linux

Machine Type = X3850-X5
system memory = 256GB

---Debugger---
A debugger is not configured

---Steps to Reproduce---
1>Install RHEL6.1alpha x64
2>Boot the system with default kernel parameters with crashkernel=auto
3>configure the kdump 
4>trigger the kdump 'echo c > /proc/sysrq-trigger'

kdump kernel loads but hangs while loading megaraid_sas.

My system is running with the latest firmware.

FYI,
---dmidecode output----
  BIOS Information
	Vendor: IBM Corp.
	Version: -[G0E140AUS-1.40]-
	Release Date: 12/14/2010

I also encountered the same issue on x3620m3 machine while loading megaraid_sas module after
triggering kdump. The hanging point is also same. Its hanging at below point.

Loading megaraid_sas.ko module
megasas: 00.00.05.29-RH1 Tue. Dec. 7 17:00:00 PDT 2010
megasas: 0x1000:0x0073:0x1014:0x03b1: bus 21:slot 0:func 0
megaraid_sas 0000:15:00.0: PCI INT A -> GSI 32 (level, low) -> IRQ 32
megasas: Waiting for FW to come to ready state
megasas: FW now in Ready state
megasas_init_mfi: fw_support_ieee=67108864
megasas: INIT adapter done
DRHD: handling fault status reg 402
INTR-REMAP: Request device [[10:00.3] fault index 87
INTR-REMAP:[fault reason 34] Present field in the IRTE entry is clear
DRHD: handling fault status reg 502
INTR-REMAP: Request device [[10:00.3] fault index 88
INTR-REMAP:[fault reason 34] Present field in the IRTE entry is clear

Below is the RAID controller information for both platforms where this issue is coming:-

1) x3850X5  - 09:00.0 RAID bus controller: LSI Logic / Symbios Logic LSI MegaSAS 9260 (rev 03).
2) x3620m3 - 15:00.0 RAID bus controller: LSI Logic / Symbios Logic MegaRAID SAS 9240 (rev 02).