Re: [BUG] commit fails with 'bus error' when working directory is on an NFS share

>
> On Sun, Dec 01, 2024 at 03:24:35PM -0700, Dmitriy Panteleyev wrote:
>
> > You are right, Jeff, I needed to run one more bisect. But it does point to
> > the commit I linked above. The bisect result is:
>
> Thanks for checking. I'm still puzzled how this commit:
>
> > 04fb96219abc0cbe46ba084997dc9066de3ac889 is the first bad commit
> > commit 04fb96219abc0cbe46ba084997dc9066de3ac889
> > Author: Jeff King <peff@peff.net>
> > Date:   Thu Nov 17 17:37:58 2022 -0500
> >
> >     parse_object(): drop extra "has" check before checking object type
> >
> >     When parsing an object of unknown type, we check to see if it's a blob,
> >     so we can use our streaming code path. This uses oid_object_info() to
> >     check the type, but before doing so we call repo_has_object_file(). This
> >     latter is pointless, as oid_object_info() will already fail if the
> >     object is missing. Checking it ahead of time just complicates the code
> >     and is a waste of resources (albeit small).
> >
> >     Let's drop the redundant check.
>
> could be the culprit, though. The diff is just
>
> diff --git a/object.c b/object.c
> index 8a74eb85e9..16eb944e98 100644
> --- a/object.c
> +++ b/object.c
> @@ -287,8 +287,7 @@ struct object *parse_object_with_flags(struct repository *r,
>         }
>
>         if ((obj && obj->type == OBJ_BLOB && repo_has_object_file(r, oid)) ||
> -           (!obj && repo_has_object_file(r, oid) &&
> -            oid_object_info(r, oid, NULL) == OBJ_BLOB)) {
> +           (!obj && oid_object_info(r, oid, NULL) == OBJ_BLOB)) {
>                 if (!skip_hash && stream_object_signature(r, repl) < 0) {
>                         error(_("hash mismatch %s"), oid_to_hex(oid));
>                         return NULL;
>
> So it is actually doing _less_, though what it is removing is going to
> just be a pack .idx lookup (or maybe a stat() call if the object is
> loose).
>
> > I am not at all familiar with the standard process for this, but the way I ran
> > the test is:
> >
> > (0. cloned test project into /nfs/proj/ and made a change)
> > 1. cloned git repo (from github) into /tmp/git/
> > 2. ran bisect in /tmp/git/, starting with v2.34.1 (good) and v2.43.1 (bad)
> > 3. ran `make all` in /tmp/git/
> > 4. in /nfs/proj/ ran `/tmp/git/bin-wrappers/git commit -m 'test'`
> > 5. repeated 2-4
>
> That sounds reasonable. I'm still not sure what's going on. It's always
> possible that commit introduced a problem, but I just don't see it. So I
> still have a suspicion (especially given that your symptom is a bus
> error) that the problem might not be deterministic.
>
> I wonder if building git with:
>
>   make SANITIZE=address,undefined
>
> and running the same test might yield anything useful.
>
> -Peff