kexec kernel panicked during kdump in RHEL 5

Issue

• After a kernel panic, the kexec kernel loads but then panics itself while attempting to dump core

• We installed RHEL5.6 x86_64 in a our server which use a MegaRaid card, and tried to kdump to local disk . But it stalled sometimes with a panic

  Unable to handle kernel NULL pointer dereference at 0000000000000170 RIP:
  [<ffffffff88042db4>] :megaraid_sas:megasas_complete_cmd_dpc+0x11b/0x4da
  PGD 8bac067 PUD 9d60067 PMD 0
  Oops: 0002 [1] SMP
  last sysfs file: /block/sdb/range
  CPU 0
  Modules linked in: ext3 jbd ata_piix libata megaraid_sas sd_mod scsi_mod
  Pid: 0, comm: swapper Not tainted 2.6.18-232.el5 #1
  RIP: 0010:[<ffffffff88042db4>]  [<ffffffff88042db4>] :megaraid_sas:megasas_complete_cmd_dpc+0x11b/0x4da
  RSP: 0018:ffffffff804a3ed0  EFLAGS: 00010046
  RAX: 0000000000000000 RBX: ffff810008eb3000 RCX: 0000000000000002
  RDX: 0000000000000102 RSI: 0000000000000282 RDI: ffff810002462a78
  RBP: ffff810008e08440 R08: 0000000000000040 R09: 0000047b50d6d234
  R10: 0000000000000000 R11: 0000000000000086 R12: 0000000000000000
  R13: ffff8100024624f8 R14: 000000000000034d R15: 000000000000034e
  FS:  0000000000000000(0000) GS:ffffffff80424000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0018 ES: 0018 CR0: 000000008005003b
  CR2: 0000000000000170 CR3: 0000000009dc3000 CR4: 00000000000006e0
  Process swapper (pid: 0, threadinfo ffffffff80454000, task ffffffff8030fb60)
  Stack:  ffff8100024624f8 ffff810002462a78 0000000000000282 ffff810002462b40
  0000000000000001 0000000000000000 000000000000000a 0000000000000000
  0000000000000000 ffffffff800967ae 0000000000000046 0000000000000001
  Call Trace:
   <IRQ>  [<ffffffff800967ae>] tasklet_action+0x89/0x125
   [<ffffffff8001245b>] __do_softirq+0x89/0x133
   [<ffffffff8005e2fc>] call_softirq+0x1c/0x28
   [<ffffffff8006d5f5>] do_softirq+0x2c/0x7d
   [<ffffffff8006d485>] do_IRQ+0xec/0xf5
   [<ffffffff8005703e>] mwait_idle+0x0/0x20
   [<ffffffff8005d615>] ret_from_intr+0x0/0xa
   <EOI>  [<ffffffff88041c24>] :megaraid_sas:megasas_shutdown+0x0/0x25
   [<ffffffff8006b981>] mwait_idle_with_hints+0x66/0x67
   [<ffffffff8005704a>] mwait_idle+0xc/0x20
   [<ffffffff800492f9>] cpu_idle+0x95/0xb8
   [<ffffffff8045f807>] start_kernel+0x220/0x225
   [<ffffffff8045f22f>] _sinittext+0x22f/0x236
  
  
  Code: c7 80 70 01 00 00 00 00 00 00 e9 98 00 00 00 0f b6 43 03 48
  RIP  [<ffffffff88042db4>] :megaraid_sas:megasas_complete_cmd_dpc+0x11b/0x4da
  RSP <ffffffff804a3ed0>
  CR2: 0000000000000170
   <0>Kernel panic - no