Subject: Re: Bugreport: pack-objects died of signal 11

From: Derrick Stolee <[email-masked]>
Date: Thu, 4 Aug 2022 16:14:03 -0400

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.

Thanks,
-Stolee