The jstests/concurrency/fsm_workloads/findAndModify_update_grow.js test occasionally aborts because of a failed WT_ASSERT in __free_update_list in bt_discard.c:
---- jstests/concurrency/fsm_workloads/findAndModify_update_grow.js ---- [...] sweep-server: src\third_party\wiredtiger\src\btree\bt_discard.c, 418: F_ISSET(session, WT_SESSION_DISCARD_FORCE) || upd->txnid == WT_TXN_ABORTED || __wt_txn_visible_all(session, upd->txnid) 2015-01-21T20:11:08.929+0000 I CONTROL mongod.exe ...\src\mongo\util\stacktrace_win.cpp(175) mongo::printStackTrace+0x43 2015-01-21T20:11:08.929+0000 I CONTROL mongod.exe ...\src\mongo\util\signal_handlers_synchronous.cpp(127) mongo::`anonymous namespace'::printSignalAndBacktrace+0x73 2015-01-21T20:11:08.929+0000 I CONTROL mongod.exe ...\src\mongo\util\signal_handlers_synchronous.cpp(194) mongo::`anonymous namespace'::abruptQuit+0x2e 2015-01-21T20:11:08.929+0000 I CONTROL mongod.exe f:\dd\vctools\crt\crtw32\misc\winsig.c(594) raise+0x35f 2015-01-21T20:11:08.929+0000 I CONTROL mongod.exe f:\dd\vctools\crt\crtw32\misc\abort.c(82) abort+0x40 2015-01-21T20:11:08.929+0000 I CONTROL mongod.exe ...\src\third_party\wiredtiger\src\os_posix\os_abort.c(25) __wt_abort+0x22 2015-01-21T20:11:08.929+0000 I CONTROL mongod.exe ...\src\third_party\wiredtiger\src\support\err.c(451) __wt_assert+0x37 2015-01-21T20:11:08.929+0000 I CONTROL mongod.exe ...\src\third_party\wiredtiger\src\btree\bt_discard.c(397) __free_update+0x94 2015-01-21T20:11:08.929+0000 I CONTROL mongod.exe ...\src\third_party\wiredtiger\src\btree\bt_discard.c(338) __free_page_row_leaf+0xaa 2015-01-21T20:11:08.929+0000 I CONTROL mongod.exe ...\src\third_party\wiredtiger\src\btree\bt_discard.c(124) __wt_page_out+0x292 2015-01-21T20:11:08.929+0000 I CONTROL mongod.exe ...\src\third_party\wiredtiger\src\evict\evict_page.c(155) __wt_rec_page_clean_update+0xe 2015-01-21T20:11:08.929+0000 I CONTROL mongod.exe ...\src\third_party\wiredtiger\src\evict\evict_file.c(120) __wt_evict_file+0x227 2015-01-21T20:11:08.929+0000 I CONTROL mongod.exe ...\src\third_party\wiredtiger\src\btree\bt_sync.c(229) __wt_cache_op+0x9d 2015-01-21T20:11:08.929+0000 I CONTROL mongod.exe ...\src\third_party\wiredtiger\src\conn\conn_dhandle.c(276) __wt_conn_btree_sync_and_close+0x7f 2015-01-21T20:11:08.930+0000 I CONTROL mongod.exe ...\src\third_party\wiredtiger\src\conn\conn_sweep.c(127) __sweep_server+0x163 2015-01-21T20:11:08.930+0000 I CONTROL kernel32.dll BaseThreadInitThunk+0xd 2015-01-21T20:11:08.930+0000 F - Got signal: 22 (SIGABRT)