There was a Jenkins failure when running the new reconfigure test called wt2719_reconfig. The call stacks from the failure are:
FAIL: test_wt2719_reconfig ========================== ASAN:SIGSEGV ================================================================= ==17893==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x0000005064cf bp 0x7f312d7ebed0 sp 0x7f312d7ebb00 T102) #0 0x5064ce in __evict_thread_run /home/jenkins/jenkins/workspace/wiredtiger-clang-sanitizer/build_posix/../src/evict/evict_lru.c:184:2 #1 0x3e6ce07554 in start_thread (/lib64/libpthread.so.0+0x3e6ce07554) #2 0x3e6cb02dec in __clone (/lib64/libc.so.6+0x3e6cb02dec) AddressSanitizer can not provide additional info. SUMMARY: AddressSanitizer: SEGV /home/jenkins/jenkins/workspace/wiredtiger-clang-sanitizer/build_posix/../src/evict/evict_lru.c:184 __evict_thread_run Thread T102 created by T92 here: #0 0x48d95f in __interceptor_pthread_create (/home/jenkins/jenkins/workspace/wiredtiger-clang-sanitizer/build_posix/test/csuite/test_wt2719_reconfig+0x48d95f) #1 0x55a15f in __wt_thread_create /home/jenkins/jenkins/workspace/wiredtiger-clang-sanitizer/build_posix/../src/os_posix/os_thread.c:22:84 #2 0x3e6ce07554 in start_thread (/lib64/libpthread.so.0+0x3e6ce07554) Thread T92 created by T1 here: #0 0x48d95f in __interceptor_pthread_create (/home/jenkins/jenkins/workspace/wiredtiger-clang-sanitizer/build_posix/test/csuite/test_wt2719_reconfig+0x48d95f) #1 0x55a15f in __wt_thread_create /home/jenkins/jenkins/workspace/wiredtiger-clang-sanitizer/build_posix/../src/os_posix/os_thread.c:22:84 #2 0x3e6ce07554 in start_thread (/lib64/libpthread.so.0+0x3e6ce07554) Thread T1 created by T0 here: #0 0x48d95f in __interceptor_pthread_create (/home/jenkins/jenkins/workspace/wiredtiger-clang-sanitizer/build_posix/test/csuite/test_wt2719_reconfig+0x48d95f) #1 0x55a15f in __wt_thread_create /home/jenkins/jenkins/workspace/wiredtiger-clang-sanitizer/build_posix/../src/os_posix/os_thread.c:22:84 #2 0x4c35d5 in main /home/jenkins/jenkins/workspace/wiredtiger-clang-sanitizer/build_posix/test/csuite/../../../test/csuite/wt2719_reconfig/main.c:212:28 #3 0x3e6ca206ff in __libc_start_main (/lib64/libc.so.6+0x3e6ca206ff) ==17893==ABORTING
The failure didn't reproduce immediately for me locally, but did reproduce within 100 runs of the test. I suspect there is a race when switching between shared and non-shared cache via reconfigure.
It's likely that this bug has existed for a long time, but is only now being uncovered because of additional testing.