* [PATCH 0/1] pathspec: fix memleak
@ 2022-08-12 8:17 Anthony Delannoy
2022-08-12 8:17 ` [PATCH 1/1] " Anthony Delannoy
0 siblings, 1 reply; 3+ messages in thread
From: Anthony Delannoy @ 2022-08-12 8:17 UTC (permalink / raw)
To: git; +Cc: Anthony Delannoy
Sending this patch to fix a memleak, created with copy_pathspec, found
thanks to the address sanitizer.
Thanks
Anthony Delannoy (1):
pathspec: fix memleak
preload-index.c | 3 +++
1 file changed, 3 insertions(+)
base-commit: 5502f77b6944eda8e26813d8f542cffe7d110aea
--
2.35.1
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH 1/1] pathspec: fix memleak
2022-08-12 8:17 [PATCH 0/1] pathspec: fix memleak Anthony Delannoy
@ 2022-08-12 8:17 ` Anthony Delannoy
2022-08-12 17:41 ` Junio C Hamano
0 siblings, 1 reply; 3+ messages in thread
From: Anthony Delannoy @ 2022-08-12 8:17 UTC (permalink / raw)
To: git; +Cc: Anthony Delannoy
Fix a memory leak occuring in case of pathspec copy in preload_index.
Direct leak of 8 byte(s) in 8 object(s) allocated from:
#0 0x7f0a353ead47 in __interceptor_malloc (/usr/lib/gcc/x86_64-pc-linux-gnu/11.3.0/libasan.so.6+0xb5d47)
#1 0x55750995e840 in do_xmalloc /home/anthony/src/c/git/wrapper.c:51
#2 0x55750995e840 in xmalloc /home/anthony/src/c/git/wrapper.c:72
#3 0x55750970f824 in copy_pathspec /home/anthony/src/c/git/pathspec.c:684
#4 0x557509717278 in preload_index /home/anthony/src/c/git/preload-index.c:135
#5 0x55750975f21e in refresh_index /home/anthony/src/c/git/read-cache.c:1633
#6 0x55750915b926 in cmd_status builtin/commit.c:1547
#7 0x5575090e1680 in run_builtin /home/anthony/src/c/git/git.c:466
#8 0x5575090e1680 in handle_builtin /home/anthony/src/c/git/git.c:720
#9 0x5575090e284a in run_argv /home/anthony/src/c/git/git.c:787
#10 0x5575090e284a in cmd_main /home/anthony/src/c/git/git.c:920
#11 0x5575090dbf82 in main /home/anthony/src/c/git/common-main.c:56
#12 0x7f0a348230ab (/lib64/libc.so.6+0x290ab)
Signed-off-by: Anthony Delannoy <anthony.2lannoy@gmail.com>
---
preload-index.c | 3 +++
1 file changed, 3 insertions(+)
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);
--
2.35.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH 1/1] pathspec: fix memleak
2022-08-12 8:17 ` [PATCH 1/1] " Anthony Delannoy
@ 2022-08-12 17:41 ` Junio C Hamano
0 siblings, 0 replies; 3+ messages in thread
From: Junio C Hamano @ 2022-08-12 17:41 UTC (permalink / raw)
To: Anthony Delannoy; +Cc: git
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);
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