It was a Distribute replicate setup with 2 replicas. Was running dbench over the mount point. 

(gdb) bt
#0  0x00002aaaad5654f9 in afr_nonblocking_entrylk_cbk (frame=0x2aaaac5382d0, cookie=0x1, this=0x6371a8, op_ret=-1, op_errno=107) at afr-lk-common.c:1137
#1  0x00002aaaad302a16 in client_entrylk (frame=0x2aaaac336d38, this=0x635e78, volume=0x635e38 "pump", loc=0x2aaab4010f38, basename=0x0, cmd=ENTRYLK_LOCK,
    type=ENTRYLK_WRLCK) at client.c:1288
#2  0x00002aaaad565f62 in afr_nonblocking_entrylk (frame=0x2aaaac5382d0, this=0x6371a8) at afr-lk-common.c:1258
#3  0x00002aaaad55d94f in afr_sh_entry_lock (frame=0x2aaaac5382d0, this=0x6371a8) at afr-self-heal-entry.c:2437
#4  0x00002aaaad55d9cd in afr_self_heal_entry (frame=0x2aaaac5382d0, this=0x6371a8) at afr-self-heal-entry.c:2457
#5  0x00002aaaad5514de in afr_sh_metadata_done (frame=0x2aaaac5382d0, this=0x6371a8) at afr-self-heal-metadata.c:96
#6  0x00002aaaad562869 in afr_unlock_common_cbk (frame=0x2aaaac5382d0, cookie=0x0, this=0x6371a8, op_ret=0, op_errno=0) at afr-lk-common.c:550
#7  0x00002aaaad562913 in afr_unlock_inodelk_cbk (frame=0x2aaaac5382d0, cookie=0x0, this=0x6371a8, op_ret=0, op_errno=0) at afr-lk-common.c:569
#8  0x00002aaaad0f1644 in pl_common_inodelk (frame=0x2aaaac3372b8, this=0x634ce8, volume=0x635e38 "pump", inode=0x2aaab0655488, cmd=6, flock=0x42a04080,
    loc=0x2aaab4010f38, fd=0x0) at inodelk.c:649
#9  0x00002aaaad0f16c2 in pl_inodelk (frame=0x2aaaac3372b8, this=0x634ce8, volume=0x635e38 "pump", loc=0x2aaab4010f38, cmd=6, flock=0x42a04080)
    at inodelk.c:659
#10 0x00002aaaad562fe8 in afr_unlock_inodelk (frame=0x2aaaac5382d0, this=0x6371a8) at afr-lk-common.c:622
#11 0x00002aaaad5674ae in afr_unlock (frame=0x2aaaac5382d0, this=0x6371a8) at afr-lk-common.c:1651
#12 0x00002aaaad55191e in afr_sh_inode_unlock (frame=0x2aaaac5382d0, this=0x6371a8) at afr-self-heal-metadata.c:138
#13 0x00002aaaad551942 in afr_sh_metadata_finish (frame=0x2aaaac5382d0, this=0x6371a8) at afr-self-heal-metadata.c:146
#14 0x00002aaaad552c92 in afr_sh_metadata_sync_prepare (frame=0x2aaaac5382d0, this=0x6371a8) at afr-self-heal-metadata.c:460
#15 0x00002aaaad553488 in afr_sh_metadata_fix (frame=0x2aaaac5382d0, this=0x6371a8) at afr-self-heal-metadata.c:564
#16 0x00002aaaad55385e in afr_sh_metadata_lookup_cbk (frame=0x2aaaac5382d0, cookie=0x0, this=0x6371a8, op_ret=0, op_errno=0, inode=0x2aaab0655488,
    buf=0x42a04490, xattr=0x647f48, postparent=0x42a04420) at afr-self-heal-metadata.c:616
#17 0x00002aaaad0ec6d6 in pl_lookup_cbk (frame=0x2aaaac337238, cookie=0x2aaaac336838, this=0x634ce8, op_ret=0, op_errno=0, inode=0x2aaab0655488, 
    buf=0x42a04490, dict=0x647f48, postparent=0x42a04420) at posix.c:1129
#18 0x00002aaaacecc97d in posix_lookup (frame=0x2aaaac336838, this=0x633a38, loc=0x2aaab4010f38, xattr_req=0x2aaab400e4b8) at posix.c:540
#19 0x00002aaaad0ecafe in pl_lookup (frame=0x2aaaac337238, this=0x634ce8, loc=0x2aaab4010f38, xattr_req=0x2aaab400e4b8) at posix.c:1171
#20 0x00002aaaad553c5c in afr_sh_metadata_lookup (frame=0x2aaaac5382d0, this=0x6371a8) at afr-self-heal-metadata.c:657
#21 0x00002aaaad553e4c in afr_sh_post_nonblocking_inodelk_cbk (frame=0x2aaaac5382d0, this=0x6371a8) at afr-self-heal-metadata.c:715
#22 0x00002aaaad5661f2 in afr_nonblocking_inodelk_cbk (frame=0x2aaaac5382d0, cookie=0x0, this=0x6371a8, op_ret=0, op_errno=0) at afr-lk-common.c:1323
#23 0x00002aaaad0f1644 in pl_common_inodelk (frame=0x2aaaac336d38, this=0x634ce8, volume=0x635e38 "pump", inode=0x2aaab0655488, cmd=6, flock=0x42a04850, 
    loc=0x2aaab4010f38, fd=0x0) at inodelk.c:649
#24 0x00002aaaad0f16c2 in pl_inodelk (frame=0x2aaaac336d38, this=0x634ce8, volume=0x635e38 "pump", loc=0x2aaab4010f38, cmd=6, flock=0x42a04850)
    at inodelk.c:659
#25 0x00002aaaad566a92 in afr_nonblocking_inodelk (frame=0x2aaaac5382d0, this=0x6371a8) at afr-lk-common.c:1410
---Type <return> to continue, or q <return> to quit---
#26 0x00002aaaad553f07 in afr_sh_metadata_lock (frame=0x2aaaac5382d0, this=0x6371a8) at afr-self-heal-metadata.c:743
#27 0x00002aaaad553f7d in afr_self_heal_metadata (frame=0x2aaaac5382d0, this=0x6371a8) at afr-self-heal-metadata.c:761
#28 0x00002aaaad54d64e in afr_sh_missing_entries_done (frame=0x2aaaac5382d0, this=0x6371a8) at afr-self-heal-common.c:782
#29 0x00002aaaad551135 in afr_self_heal (frame=0x2aaaac336a38, this=0x6371a8) at afr-self-heal-common.c:1665
#30 0x00002aaaad568fc8 in afr_lookup_done (frame=0x2aaaac336a38, this=0x6371a8, lookup_buf=0x2aaab4015608) at afr-common.c:688
#31 0x00002aaaad569d3d in afr_revalidate_lookup_cbk (frame=0x2aaaac336a38, cookie=0x0, this=0x6371a8, op_ret=0, op_errno=22, inode=0x2aaab0655488,
    buf=0x42a04df0, xattr=0x2aaab4004e48, postparent=0x42a04d80) at afr-common.c:976
#32 0x00002aaaad0ec6d6 in pl_lookup_cbk (frame=0x2aaaac336eb8, cookie=0x2aaaac336738, this=0x634ce8, op_ret=0, op_errno=22, inode=0x2aaab0655488,
    buf=0x42a04df0, dict=0x2aaab4004e48, postparent=0x42a04d80) at posix.c:1129
#33 0x00002aaaacecc97d in posix_lookup (frame=0x2aaaac336738, this=0x633a38, loc=0x2aaaac758070, xattr_req=0x65fab8) at posix.c:540
#34 0x00002aaaad0ecafe in pl_lookup (frame=0x2aaaac336eb8, this=0x634ce8, loc=0x2aaaac758070, xattr_req=0x65fab8) at posix.c:1171
#35 0x00002aaaad56a472 in afr_lookup (frame=0x2aaaac336a38, this=0x6371a8, loc=0x2aaaac758070, xattr_req=0x65fab8) at afr-common.c:1091
#36 0x00002aaaad78a1a1 in iot_lookup_wrapper (frame=0x2aaaac336138, this=0x6383b8, loc=0x2aaaac758070, xattr_req=0x65fab8) at io-threads.c:178
#37 0x00002aaaaacf8be1 in call_resume_wind (stub=0x2aaaac758038) at call-stub.c:2420
#38 0x00002aaaaacfec6a in call_resume (stub=0x2aaaac758038) at call-stub.c:3861
#39 0x00002aaaad789d8e in iot_worker (data=0x63d198) at io-threads.c:118
#40 0x00002aaaab567407 in start_thread () from /lib64/libpthread.so.0
#41 0x00002aaaab850b0d in clone () from /lib64/libc.so.6

Logs & entire core in /mnt/bugs/bugid