The real problem is that you hit a panic during xfstests.

kernel BUG at fs/ext4/extents.c:1919! 
invalid opcode: 0000 [#1] SMP  
last sysfs file: /sys/devices/virtual/block/loop0/dev 
Modules linked in: ext4 jbd2 nfs fscache(T) nfsd lockd nfs_acl auth_rpcgss exportfs sunrpc cpufreq_ondemand powernow_k8 ipv6 dm_mirror dm_region_hash dm_log bnx2 sg microcode serio_raw k10temp i2c_piix4 ext3 jbd mbcache dm_round_robin scsi_dh_rdac sd_mod crc_t10dif mptsas mptscsih mptbase scsi_transport_sas qla2xxx scsi_transport_fc scsi_tgt radeon ttm drm_kms_helper drm hwmon i2c_algo_bit i2c_core dm_multipath dm_mod [last unloaded: scsi_wait_scan] 
 
Pid: 11886, comm: fiemap-tester Tainted: G           ---------------- T (2.6.32-131.6.1.el6.i686 #1) BladeCenter LS22 -[79013SG]- 
EIP: 0060:[<fe4f190b>] EFLAGS: 00210212 CPU: 0 
EIP is at ext4_ext_walk_space+0x29b/0x2f0 [ext4] 
EAX: 00000000 EBX: 00000119 ECX: 0000008a EDX: 00000085 
ESI: edfb96c0 EDI: 00000001 EBP: ea5201bc ESP: dc147e88 
 DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 
Process fiemap-tester (pid: 11886, ti=dc146000 task=ee19d570 task.ti=dc146000) 
Stack: 
 ea5201bc dc147f68 00001000 dc147ed8 00000004 000000e8 00000000 e731bd64 
<0> 00000201 e731bd54 00000004 e731bcdc 00048cca 00000000 00000000 00000118 
<0> 000000e8 00000001 e731bd64 dc147f68 fffffee8 00000119 fe4f1aca fe4efac0 
Call Trace: 
 [<fe4f1aca>] ? ext4_fiemap+0x16a/0x1e0 [ext4] 
 [<fe4efac0>] ? ext4_ext_fiemap_cb+0x0/0x210 [ext4] 
 [<c05a4f72>] ? file_has_perm+0xd2/0xe0 
 [<c05380b5>] ? do_vfs_ioctl+0x505/0x5c0 
 [<c05381e6>] ? sys_ioctl+0x76/0x90 
 [<c04ad970>] ? __audit_syscall_exit+0x220/0x250 
 [<c0409bdf>] ? sysenter_do_call+0x12/0x28 
Code: e9 eb fe ff ff 8b 4c 24 1c bd fb ff ff ff c7 44 24 08 54 be 50 fe c7 04 24 26 4d 50 fe 89 4c 24 04 e8 0a 71 ff ff e9 c5 fe ff ff <0f> 0b eb fe 0f 0b eb fe 0f 0b 8d 74 26 00 8d bc 27 00 00 00 00  
EIP: [<fe4f190b>] ext4_ext_walk_space+0x29b/0x2f0 [ext4] SS:ESP 0068:dc147e88 

The second problem is that your kdump is misconfigured.

Saving to the local filesystem /dev/sdc2 
e2fsck 1.41.12 (17-May-2010) 
fsck.ext3: No such device or address while trying to open /dev/sdc2 
Possibly non-existent or swap device? 
mount: mounting /dev/sdc2 on /mnt failed: No such device or address 
Attempting to enter user-space to capture vmcore 

So, it then tried to enter user-space to capture vmcore which your system was running out of free memory from reserved 128MB at that time, but unfortunately oom won't work in kdump kernel.

The bug is in:

ext4_ext_walk_space()
{
...
        while (block < last && block != EXT_MAX_BLOCK) {
...
                BUG_ON(end <= start);


Given that this function is ONLY used for fiemap, BUG_ON is quite a terrible result - we should at least just fail the fiemap call with a message I suppose rather than taking down the box...

The xfstests 225 panic issue should be a dup of bug 692063

Duping because the bug summary is identical to 692063.

Please open a new bug explicitly for the memory-related issues you mentioned; I'm not quite sure what the actual issue is there.

Thanks,
-Eric

*** This bug has been marked as a duplicate of bug 692063 ***