From: Junio C Hamano <gitster@pobox.com>
To: Anthony Delannoy <anthony.2lannoy@gmail.com>
Cc: git@vger.kernel.org
Subject: Re: [PATCH 1/1] pathspec: fix memleak
Date: Fri, 12 Aug 2022 10:41:08 -0700 [thread overview]
Message-ID: <xmqqsfm1bbrf.fsf@gitster.g> (raw)
In-Reply-To: <20220812081744.456280-2-anthony.2lannoy@gmail.com> (Anthony Delannoy's message of "Fri, 12 Aug 2022 10:17:44 +0200")
Anthony Delannoy <anthony.2lannoy@gmail.com> writes:
> diff --git a/preload-index.c b/preload-index.c
> index e5529a5863..a05f4d1390 100644
> --- a/preload-index.c
> +++ b/preload-index.c
> @@ -148,6 +148,9 @@ void preload_index(struct index_state *index,
> if (pthread_join(p->pthread, NULL))
> die("unable to join threaded lstat");
> t2_sum_lstat += p->t2_nr_lstat;
> +
> + if (pathspec)
> + free(p->pathspec.items);
> }
> stop_progress(&pd.progress);
Given the way how copy_pathspec() makes a deep copy of a pathspec, I
suspect that this is still leaking all the resources held by the
array that is freed here. Let's take a look:
void copy_pathspec(struct pathspec *dst, const struct pathspec *src)
{
int i, j;
*dst = *src;
ALLOC_ARRAY(dst->items, dst->nr);
COPY_ARRAY(dst->items, src->items, dst->nr);
Here, we copy the array of "struct pathspec_item". But that is not
enough because ...
for (i = 0; i < dst->nr; i++) {
struct pathspec_item *d = &dst->items[i];
struct pathspec_item *s = &src->items[i];
d->match = xstrdup(s->match);
d->original = xstrdup(s->original);
... each "struct pathspec_item" instance has pointer members like
these, and the copying of the array made these strings shared
between the src and dst arrays. Here we make a copy of the string
owned by the element in the src array and give the copy to the
element in the dst array.
ALLOC_ARRAY(d->attr_match, d->attr_match_nr);
COPY_ARRAY(d->attr_match, s->attr_match, d->attr_match_nr);
Likewise for a separate array pointed by a member in "struct
pathspec_item" ...
for (j = 0; j < d->attr_match_nr; j++) {
const char *value = s->attr_match[j].value;
d->attr_match[j].value = xstrdup_or_null(value);
... which has a pointer member here ...
}
d->attr_check = attr_check_dup(s->attr_check);
... and here. Both are deep-copied.
}
}
There is pathspec.c::clear_pathspec() API function, which looks as
if it was made for this exact use case.
I wonder if this is a good place to use it, perhaps like the
attached patch.
preload-index.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git c/preload-index.c w/preload-index.c
index e5529a5863..100f7a374d 100644
--- c/preload-index.c
+++ w/preload-index.c
@@ -151,6 +151,12 @@ void preload_index(struct index_state *index,
}
stop_progress(&pd.progress);
+ if (pathspec) {
+ /* earlier we made deep copies for each thread to work with */
+ for (i = 0; i < threads; i++)
+ clear_pathspec(&data[i].pathspec);
+ }
+
trace_performance_leave("preload index");
trace2_data_intmax("index", NULL, "preload/sum_lstat", t2_sum_lstat);
prev parent reply other threads:[~2022-08-12 17:41 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-12 8:17 [PATCH 0/1] pathspec: fix memleak Anthony Delannoy
2022-08-12 8:17 ` [PATCH 1/1] " Anthony Delannoy
2022-08-12 17:41 ` Junio C Hamano [this message]
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