Found this core in nightly sanity run:

(gdb) bt
#0  0x00002aaaac18e10f in sh_diff_checksum_cbk (rw_frame=0x2aaab000bca0, cookie=0x2aaab00efd60, this=0x2aaab00550c0, op_ret=0, op_errno=0, 
    weak_checksum=4242538648, strong_checksum=0x2aaab00ccb04 "�f\003\032\201\020�V���\033�+�Y")
    at ../../../../../xlators/cluster/afr/src/afr-self-heal-algorithm.c:688
#1  0x00002aaaabf3f219 in client_rchecksum_cbk (frame=0x2aaab0025910, hdr=0x2aaab00ccae0, hdrlen=53, iobuf=0x0)
    at ../../../../../xlators/protocol/client/src/client-protocol.c:5766
#2  0x00002aaaabf40a2a in protocol_client_interpret (this=0x610e40, trans=0x614130, hdr_p=0x2aaab00ccae0 "", hdrlen=53, iobuf=0x0)
    at ../../../../../xlators/protocol/client/src/client-protocol.c:6484
#3  0x00002aaaabf416f0 in protocol_client_pollin (this=0x610e40, trans=0x614130) at ../../../../../xlators/protocol/client/src/client-protocol.c:6782
#4  0x00002aaaabf41d67 in notify (this=0x610e40, event=2, data=0x614130) at ../../../../../xlators/protocol/client/src/client-protocol.c:6901
#5  0x00002aaaaacdf7a7 in xlator_notify (xl=0x610e40, event=2, data=0x614130) at ../../../libglusterfs/src/xlator.c:923
#6  0x00002aaaac9efd6a in socket_event_poll_in (this=0x614130) at ../../../../transport/socket/src/socket.c:729
#7  0x00002aaaac9f005f in socket_event_handler (fd=12, idx=2, data=0x614130, poll_in=1, poll_out=0, poll_err=0)
    at ../../../../transport/socket/src/socket.c:829
#8  0x00002aaaaad02369 in event_dispatch_epoll_handler (event_pool=0x60b8a0, events=0x616fd0, i=0) at ../../../libglusterfs/src/event.c:804
#9  0x00002aaaaad0253e in event_dispatch_epoll (event_pool=0x60b8a0) at ../../../libglusterfs/src/event.c:867
#10 0x00002aaaaad02854 in event_dispatch (event_pool=0x60b8a0) at ../../../libglusterfs/src/event.c:975
#11 0x0000000000405e1d in main (argc=8, argv=0x7fff5c2abf28) at ../../../glusterfsd/src/glusterfsd.c:1377
(gdb) p rw_sh
$1 = (afr_self_heal_t *) 0x1f40

Log files and core present in /share/tickets/<bug-id>