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Re: [PATCH 05/11] builtin/repack.c: avoid leaking child arguments

From
Derrick Stolee <stolee@gmail.com>
Date
Oct 21, 2021, 13:32 UTC
Message-ID
<67b553b7-4e69-9906-b237-9c44cf8aaf44@gmail.com>
In-Reply-To
<a68c77c00638bef7e8ce88929015a587d2d1b6f8.1634787555.git.me@ttaylorr.com>
On 10/20/2021 11:39 PM, Taylor Blau wrote:
Show 26 quoted lines
> `git repack` invokes a handful of child processes: one to write the
> actual pack, and optionally ones to repack promisor objects and update
> the MIDX.
> 
> In none of these cases do we bother to call child_process_clear(), which
> frees the memory associated with each child's arguments and environment.
> 
> In order to do so, tweak each function that spawns a child process to
> have a `cleanup` label that we always visit before returning from each
> function. Then, make sure that we call child_process_clear() as a part
> of that label.
> 
> Signed-off-by: Taylor Blau <me@ttaylorr.com>
> ---
>  builtin/repack.c | 35 ++++++++++++++++++++++++-----------
>  1 file changed, 24 insertions(+), 11 deletions(-)
> 
> diff --git a/builtin/repack.c b/builtin/repack.c
> index 0b2d1e5d82..d16bab09a4 100644
> --- a/builtin/repack.c
> +++ b/builtin/repack.c
> @@ -244,6 +244,7 @@ static void repack_promisor_objects(const struct pack_objects_args *args,
>  	struct child_process cmd = CHILD_PROCESS_INIT;
>  	FILE *out;
>  	struct strbuf line = STRBUF_INIT;
> +	int ret = 0;

nit: "ret" is short for "return" which makes me think "this will be used as 'return ret;'" but we don't do that. Instead, we use it as the _result_ of an inner call:

Show 8 quoted lines
> -	if (finish_command(&cmd))
> +	ret = finish_command(&cmd);
> +
> +cleanup:
> +	child_process_clear(&cmd);
> +
> +	if (ret)
>  		die(_("could not finish pack-objects to repack promisor objects"));
For that reason, I would rename this to "res" or "result".
Show 7 quoted lines
> -	return finish_command(&cmd);
> +	ret = finish_command(&cmd);
> +
> +cleanup:
> +	child_process_clear(&cmd);
> +
> +	return ret;

Here, you are taking the result of an inner call, but actually returning it. This makes sense to be "ret".

Show 11 quoted lines
> +cleanup:
>  	string_list_clear(&names, 0);
>  	string_list_clear(&rollback, 0);
>  	string_list_clear(&existing_nonkept_packs, 0);
>  	string_list_clear(&existing_kept_packs, 0);
>  	clear_pack_geometry(geometry);
>  	strbuf_release(&line);
> +	child_process_clear(&cmd);
>  
> -	return 0;
> +	return ret;
Also here is good.

Thanks, -Stolee

Previous: Taylor BlauNext: Junio C Hamano
Message 14 of 63 in “midx: clean up t5319 under 'SANITIZE=leak'”
  1. 00/11 midx: clean up t5319 under 'SANITIZE=leak'Taylor Blau, Oct 21, 2021
  2. 01/11 midx.c: clean up chunkfile after reading the MIDXTaylor Blau, Oct 21, 2021
  3. Junio C HamanoOct 21, 2021
  4. Ævar Arnfjörð BjarmasonOct 21, 2021
  5. Junio C HamanoOct 21, 2021
  6. Taylor BlauOct 22, 2021
  7. 02/11 midx.c: don't leak MIDX from verify_midx_fileTaylor Blau, Oct 21, 2021
  8. Eric SunshineOct 21, 2021
  9. Junio C HamanoOct 21, 2021
  10. Junio C HamanoOct 21, 2021
  11. 03/11 t/helper/test-read-midx.c: free MIDX within read_midx_file()Taylor Blau, Oct 21, 2021
  12. 04/11 builtin/pack-objects.c: don't leak memory via argumentsTaylor Blau, Oct 21, 2021
  13. 05/11 builtin/repack.c: avoid leaking child argumentsTaylor Blau, Oct 21, 2021
  14. Derrick StoleeOct 21, 2021
  15. Junio C HamanoOct 21, 2021
  16. Junio C HamanoOct 21, 2021
  17. Taylor BlauOct 22, 2021
  18. 06/11 builtin/multi-pack-index.c: don't leak concatenated optionsTaylor Blau, Oct 21, 2021
  19. 07/11 pack-bitmap.c: avoid leaking via midx_bitmap_filename()Taylor Blau, Oct 21, 2021
  20. Junio C HamanoOct 21, 2021
  21. Taylor BlauOct 22, 2021
  22. 08/11 pack-bitmap.c: don't leak type-level bitmapsTaylor Blau, Oct 21, 2021
  23. Junio C HamanoOct 21, 2021
  24. 09/11 pack-bitmap.c: more aggressively free in free_bitmap_index()Taylor Blau, Oct 21, 2021
  25. Eric SunshineOct 21, 2021
  26. Junio C HamanoOct 21, 2021
  27. Taylor BlauOct 22, 2021
  28. Junio C HamanoOct 21, 2021
  29. 11/11 t5319: UNLEAK() the remaining leaksTaylor Blau, Oct 21, 2021
  30. 10/11 pack-bitmap-write.c: don't return without stop_progress()Taylor Blau, Oct 21, 2021
  31. Eric SunshineOct 21, 2021
  32. Ævar Arnfjörð BjarmasonOct 21, 2021
  33. Junio C HamanoOct 21, 2021
  34. Taylor BlauOct 22, 2021
  35. Junio C HamanoOct 23, 2021
  36. SubmittingPatchs: clarify choice of base and testingJunio C Hamano, Oct 23, 2021
  37. Ævar Arnfjörð BjarmasonOct 23, 2021
  38. Junio C HamanoOct 23, 2021
  39. Junio C HamanoOct 23, 2021
  40. Fabian StelzerOct 25, 2021
  41. Junio C HamanoOct 25, 2021
  42. Junio C HamanoOct 25, 2021
  43. Junio C HamanoOct 25, 2021
  44. SubmittingPatchs: clarify choice of base and testingJunio C Hamano, Dec 23, 2021
  45. Elijah NewrenDec 28, 2021
  46. Fabian StelzerDec 30, 2021
  47. Re* [PATCH v2] SubmittingPatchs: clarify choice of base and testingJunio C Hamano, Dec 30, 2021
  48. Ævar Arnfjörð BjarmasonOct 21, 2021
  49. Taylor BlauOct 22, 2021
  50. Ævar Arnfjörð BjarmasonOct 22, 2021
  51. leak tests: add an interface to the LSAN_OPTIONS "suppressions"Ævar Arnfjörð Bjarmason, Oct 22, 2021
  52. Taylor BlauOct 26, 2021
  53. Jeff KingOct 26, 2021
  54. Taylor BlauOct 26, 2021
  55. Jeff KingOct 26, 2021
  56. Ævar Arnfjörð BjarmasonOct 27, 2021
  57. Jeff KingOct 27, 2021
  58. Junio C HamanoOct 27, 2021
  59. Ævar Arnfjörð BjarmasonOct 27, 2021
  60. Jeff KingOct 29, 2021
  61. Jeff KingOct 29, 2021
  62. Ævar Arnfjörð BjarmasonOct 27, 2021
  63. Derrick StoleeOct 21, 2021

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