In 9ac3f0e (pack-objects: fix performance issues on packing large deltas, 2018-07-22), a mutex was introduced that is used to guard the call to set the delta size. This commit added code to initialize it, but at an incorrect spot: in init_threaded_search(), while the call to oe_set_delta_size() (and hence to packing_data_lock()) can happen in the call chain check_object() <- get_object_details() <-prepare_pack() <- cmd_pack_objects(), which is long before theprepare_pack() function calls ll_find_deltas() (which initializes the threaded search). Another tell-tale that the mutex was initialized in an incorrect spot is that the function to initialize it lives in builtin/, while the code that uses the mutex is defined in a libgit.a header file. Let's use a more appropriate function: prepare_packing_data(), which not only lives in libgit.a, but has to be called before thepacking_data struct is used that contains that mutex. Johannes Schindelin (3): Fix typo 'detla' -> 'delta' pack-objects (mingw): demonstrate a segmentation fault with large deltas pack-objects (mingw): initialize `packing_data` mutex in the correct spot builtin/pack-objects.c | 1 - pack-objects.c | 3 +++ pack-objects.h | 2 +- t/t5321-pack-large-objects.sh | 32 ++++++++++++++++++++++++++++++++ 4 files changed, 36 insertions(+), 2 deletions(-) create mode 100755 t/t5321-pack-large-objects.sh base-commit: 5a0cc8aca797dbd7d2be3b67458ff880ed45cddf Published-As: https://github.com/gitgitgadget/git/releases/tags/pr-47%2Fjamill%2Ffix-gc-segfault-v1 Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-47/jamill/fix-gc-segfault-v1 Pull-Request: https://github.com/gitgitgadget/git/pull/47 -- gitgitgadget