Ceph

On an assert:
assert(begin->last_committed == last_committed);
(gdb) bt
#0 0x00007f39eacfdf45 in GI_raise (sig=<value optimized out>) at ../nptl/sysdeps/unix/sysv/linux/raise.c:64
#1 0x00007f39ead00d80 in *_GI_abort () at abort.c:88
#2 0x00007f39eacf708a in *_GI_assert_fail (assertion=0x55a690 "begin->last_committed == last_committed", file=<value optimized out>, line=386, function=0x55b080 "void Paxos::handle_begin(MMonPaxos)") at assert.c:78
#3 0x00000000004752a7 in Paxos::handle_begin (this=0xcf01b0, begin=0x7f39dc0019b0) at mon/Paxos.cc:386
#4 0x000000000047a2cb in Paxos::dispatch (this=0xcf01b0, m=0x7f39dc0019b0) at mon/Paxos.cc:827
#5 0x000000000046911c in Monitor::_ms_dispatch (this=<value optimized out>, m=0x7f39dc0019b0) at mon/Monitor.cc:716
#6 0x0000000000473bd1 in Monitor::ms_dispatch(Message*) ()
#7 0x00000000004526e9 in Messenger::ms_deliver_dispatch (this=<value optimized out>) at msg/Messenger.h:97
#8 SimpleMessenger::dispatch_entry (this=<value optimized out>) at msg/SimpleMessenger.cc:323
#9 0x0000000000445a1c in SimpleMessenger::DispatchThread::entry (this=0xce4ad0) at msg/SimpleMessenger.h:494
#10 0x000000000045741a in Thread::_entry_func (arg=0x5850) at ./common/Thread.h:39
#11 0x00007f39ebb7173a in start_thread (arg=<value optimized out>) at pthread_create.c:300
#12 0x00007f39ead9769d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#13 0x0000000000000000 in ?? ()

I assume this is from Sage's most recent changes on May 26, since I noticed it on unstable branch yesterday afternoon. The workload was iozone running in UML on pudgy; this may be intermittent but I'm not sure.
(I kept the logs in my home folder if you want them.)