@matheusbsbs / matheus-bagliano / commits / 8d60e9d201

merge-ort: fix small memory leak in detect_and_process_renames()

detect_and_process_renames() detects renames on both sides of history and then combines these into a single diff_queue_struct. The combined diff_queue_struct needs to be able to hold the renames found on either side, and since it knows the (maximum) size it needs, it pre-emptively grows the array to the appropriate size: ALLOC_GROW(combined.queue, renames->pairs[1].nr + renames->pairs[2].nr, combined.alloc); It then collects the items from each side: collect_renames(opt, &combined, MERGE_SIDE1, ...) collect_renames(opt, &combined, MERGE_SIDE2, ...) Note, though, that collect_renames() sometimes determines that some pairs are unnecessary and does not include them in the combined array. When it is done, detect_and_process_renames() frees this memory: if (combined.nr) { ... free(combined.queue); } The problem is that sometimes even when there are pairs, none of them are necessary. Instead of checking combined.nr, just remove the if-check; free() knows to skip NULL pointers. This change fixes the following memory leak, as reported by valgrind: ==PID== 192 bytes in 1 blocks are definitely lost in loss record 107 of 134 ==PID== at 0xADDRESS: malloc ==PID== by 0xADDRESS: realloc ==PID== by 0xADDRESS: xrealloc (wrapper.c:126) ==PID== by 0xADDRESS: detect_and_process_renames (merge-ort.c:3134) ==PID== by 0xADDRESS: merge_ort_nonrecursive_internal (merge-ort.c:4610) ==PID== by 0xADDRESS: merge_ort_internal (merge-ort.c:4709) ==PID== by 0xADDRESS: merge_incore_recursive (merge-ort.c:4760) ==PID== by 0xADDRESS: merge_ort_recursive (merge-ort-wrappers.c:57) ==PID== by 0xADDRESS: try_merge_strategy (merge.c:753) ==PID== by 0xADDRESS: cmd_merge (merge.c:1676) ==PID== by 0xADDRESS: run_builtin (git.c:461) ==PID== by 0xADDRESS: handle_builtin (git.c:713) ==PID== by 0xADDRESS: run_argv (git.c:780) ==PID== by 0xADDRESS: cmd_main (git.c:911) ==PID== by 0xADDRESS: main (common-main.c:52) Reported-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Elijah Newren committed Feb 20, 2022 at 01:29 UTC 8d60e9d2010d34f8c8ca65967ed02a2b06d74dc5

1 file changed +5 -10

merge-ort.c

+5 -10

@@ -3086,12 +3086,11 @@ static int detect_and_process_renames(struct merge_options *opt,

3086 struct tree *side1,

3087 struct tree *side2)

3088 {

3089 - struct diff_queue_struct combined;

3089 + struct diff_queue_struct combined = { 0 };

3090 struct rename_info *renames = &opt->priv->renames;

3091 - int need_dir_renames, s, clean = 1;

3091 + int need_dir_renames, s, i, clean = 1;

3092 unsigned detection_run = 0;

3093

3094 - memset(&combined, 0, sizeof(combined));

3094 if (!possible_renames(renames))

3095 goto cleanup;

3096

@@ -3175,13 +3174,9 @@ simple_cleanup:

3174 free(renames->pairs[s].queue);

3175 DIFF_QUEUE_CLEAR(&renames->pairs[s]);

3176 }

3178 - if (combined.nr) {

3179 - int i;

3180 - for (i = 0; i < combined.nr; i++)

3181 - pool_diff_free_filepair(&opt->priv->pool,

3182 - combined.queue[i]);

3183 - free(combined.queue);

3184 - }

3177 + for (i = 0; i < combined.nr; i++)

3178 + pool_diff_free_filepair(&opt->priv->pool, combined.queue[i]);

3179 + free(combined.queue);

3180

3181 return clean;

3182 }