We're seeing Seg Faults when under high load. The first time this happened was when we were loading data from one collection to another. This caused the primary to crash and by the time we caught it had gotten too far behind the oplog on the other servers in the replica set. So, we dropped everything in the data dir and allowed it to resync. Now we're seeing the same "Invalid access at address" during the resync.

The log file shows:
Wed Apr 10 14:17:13.529 [conn8] authenticate db: apm

{ authenticate: 1, user: "apmui", nonce: "ccb12593a3cab52a", key: "58f35b791cc2537221649704a50caee6" }

Wed Apr 10 14:17:13.529 [conn9] authenticate db: apm

{ authenticate: 1, user: "apmui", nonce: "ccb12593a3cab52a", key: "58f35b791cc2537221649704a50caee6" }

Wed Apr 10 14:17:13.529 [conn8] auth: couldn't find user apmui@apm, apm.system.users
Wed Apr 10 14:17:13.529 [conn9] auth: couldn't find user apmui@apm, apm.system.users
Wed Apr 10 14:17:18.559 Wed Apr 10 14:17:18.559 Invalid access at address: 0x7f5de016fff0 from thread: conn9
Invalid access at address: 0x7f5de0371ff0 from thread: conn8

Wed Apr 10 14:17:18.586 Got signal: 11 (Segmentation fault).

Wed Apr 10 14:17:18.586 Got signal: 11 (Segmentation fault).