On Thu, Aug 04 2022, Derrick Stolee wrote: > On 8/4/2022 2:21 PM, Emily Noneman wrote: >> The stack trace: >> Thread 2 received signal SIGSEGV, Segmentation fault. >> git_config_check_init (repo=0x0) at config.c:2538 >> 2538 if (repo->config && repo->config->hash_initialized) >> (gdb) bt >> #0 git_config_check_init (repo=0x0) at config.c:2538 >> #1 0x00000001001197a8 in repo_config_get_string (repo=0x0, key=0x1002a3c49 "status.showuntrackedfiles", dest=0x0, dest@entry=0x7ff7bfefc1f0) at config.c:2574 >> #2 0x000000010014a85b in new_untracked_cache_flags (istate=0x0) at dir.c:2781 >> #3 new_untracked_cache (istate=0x0, flags=-1) at dir.c:2797 >> #4 0x00000001001d68f1 in tweak_untracked_cache (istate=0x7ff7bfefc7e0) at read-cache.c:1996 > > Here is where things are confusing: > > * tweak_untracked_cache() takes an 'istate' that is non-NULL here. > > * The next spot in the stack is new_untracked_cache() with a NULL 'istate'. > > The only way these are connected is by a missing stack frame (probably > optimized out) calling add_untracked_cache(). Still, it should be > passing 'istate' throughout this process. > > The repo_config_get_string() call must also be coming from > new_untracked_cache_flags() which is again a missing stack frame, > but is called from new_untracked_cache(). Strangely, it's using > a NULL 'repo' here which should have come from 'istate->repo', so > we should have had a segfault earlier. > > Sorry for the drive-by commentary without any solution. This is > just genuinely puzzling to me. I think this segfault might be fixed by this patch of mine, which I wrote for something unrelated back in April (but it was never sent to the list). https://github.com/avar/git/commit/d83bfa866ba Emily and/or Paul: Are you able to test the patch to see if it would work, diff here: https://github.com/avar/git/commit/d83bfa866ba.patch It's exactly on the codepath in this stacktrace, i.e. add_index_objects_to_pending() in revision.c will do before/after: - struct index_state istate = { NULL }; + struct index_state istate = { .repo = revs->repo }; Then when we're all the way down in new_untracked_cache_flags() we do: struct repository *repo = istate->repo; Which then calls (indirectly) git_config_check_init(), and we segfault not because istate is NULL, but because the "repo" it's carrying is NULL. But maybe I'm wrong, I haven't been able to reproduce this. The reason I wrote that patch (as can be seen if you peek at the WIP branch it's at) is because I ran into a similar dependency between the_index and the_repo & an istate variable being passed around with fsmonitor-settings.c.
