The merge of WT-6215 revealed a memory leak in the new schema rename code adding in the backup block mods.
https://evergreen.mongodb.com/task/wiredtiger_rhel80_make_check_asan_test_7365ea188aaf1aa094824def8822d816752dcab2_20_07_22_13_46_40/0
[2020/07/22 14:40:30.061] ==8550==ERROR: LeakSanitizer: detected memory leaks [2020/07/22 14:40:30.061] Direct leak of 19639 byte(s) in 16 object(s) allocated from: [2020/07/22 14:40:30.061] #0 0x4c56f3 in malloc /data/mci/a4affc48e8e26b0b96dee0d807896f39/toolchain-builder/tmp/build-llvm.sh-I7H/llvm/projects/compiler-rt/lib/asan/asan_malloc_linux.cc:146:3 [2020/07/22 14:40:30.061] #1 0x7f95d2c0a08e in __wt_malloc /data/mci/c5f18007c218fb4414b18121188ca672/wiredtiger/build_posix/../src/os_common/os_alloc.c:81:14 [2020/07/22 14:40:30.061] #2 0x7f95d2c0ba9f in __wt_strndup /data/mci/c5f18007c218fb4414b18121188ca672/wiredtiger/build_posix/../src/os_common/os_alloc.c:262:5 [2020/07/22 14:40:30.061] #3 0x7f95d2be270a in __wt_meta_block_metadata /data/mci/c5f18007c218fb4414b18121188ca672/wiredtiger/build_posix/../src/meta/meta_ckpt.c:365:5 [2020/07/22 14:40:30.061] #4 0x7f95d2be2ea5 in __wt_meta_blk_mods_load /data/mci/c5f18007c218fb4414b18121188ca672/wiredtiger/build_posix/../src/meta/meta_ckpt.c:472:5 [2020/07/22 14:40:30.061] #5 0x7f95d2d2f84a in __rename_blkmod /data/mci/c5f18007c218fb4414b18121188ca672/wiredtiger/build_posix/../src/schema/schema_rename.c:26:5 [2020/07/22 14:40:30.061] #6 0x7f95d2d2e309 in __rename_file /data/mci/c5f18007c218fb4414b18121188ca672/wiredtiger/build_posix/../src/schema/schema_rename.c:89:9 [2020/07/22 14:40:30.061] #7 0x7f95d2d2d30e in __schema_rename /data/mci/c5f18007c218fb4414b18121188ca672/wiredtiger/build_posix/../src/schema/schema_rename.c:300:15 [2020/07/22 14:40:30.061] #8 0x7f95d2d2cebc in __wt_schema_rename /data/mci/c5f18007c218fb4414b18121188ca672/wiredtiger/build_posix/../src/schema/schema_rename.c:329:11 [2020/07/22 14:40:30.061] #9 0x7f95d2d313d6 in __rename_tree /data/mci/c5f18007c218fb4414b18121188ca672/wiredtiger/build_posix/../src/schema/schema_rename.c:185:5 [2020/07/22 14:40:30.061] #10 0x7f95d2d2ec50 in __rename_table /data/mci/c5f18007c218fb4414b18121188ca672/wiredtiger/build_posix/../src/schema/schema_rename.c:251:9 [2020/07/22 14:40:30.061] #11 0x7f95d2d2d456 in __schema_rename /data/mci/c5f18007c218fb4414b18121188ca672/wiredtiger/build_posix/../src/schema/schema_rename.c:304:15 [2020/07/22 14:40:30.061] #12 0x7f95d2d2cebc in __wt_schema_rename /data/mci/c5f18007c218fb4414b18121188ca672/wiredtiger/build_posix/../src/schema/schema_rename.c:329:11 [2020/07/22 14:40:30.061] #13 0x7f95d2d608c2 in __session_rename /data/mci/c5f18007c218fb4414b18121188ca672/wiredtiger/build_posix/../src/session/session_api.c:917:5 [2020/07/22 14:40:30.061] #14 0x4f6f30 in rename_table /data/mci/c5f18007c218fb4414b18121188ca672/wiredtiger/build_posix/test/csuite/../../../test/csuite/incr_backup/main.c:432:5 [2020/07/22 14:40:30.061] #15 0x4f5bd7 in main /data/mci/c5f18007c218fb4414b18121188ca672/wiredtiger/build_posix/test/csuite/../../../test/csuite/incr_backup/main.c:861:21 [2020/07/22 14:40:30.061] #16 0x7f95d1606812 in __libc_start_main (/lib64/libc.so.6+0x23812)