memcached shutdown hang (rabalancing hang symptom)

memcached occasionally hangs when shut down using the stdin handler (which makes a server-api callback) in some kind of weird dl resolution code:

Thread 1 (Thread -1208543552 (LWP 13704)):
#0 0x00c4b402 in __kernel_vsyscall ()
#1 0x00987956 in nanosleep () from /lib/libc.so.6
#2 0x009c145c in usleep () from /lib/libc.so.6
#3 0x00e6dabc in ?? ()
#4 0x000003e8 in ?? ()
#5 0x008e7450 in _dl_runtime_resolve () from /lib/ld-linux.so.2
#6 0x00e51607 in ?? ()
#7 0x09ef0508 in ?? ()
#8 0x00000001 in ?? ()
#9 0x00000005 in ?? ()
#10 0x00000000 in ?? ()
#0 0x00c4b402 in __kernel_vsyscall ()