Re: [PATCH 1/2] log: UNLEAK rev to silence a large number of leaks
- From
Ævar Arnfjörð Bjarmason <avarab@gmail.com>
- Date
- Sep 19, 2021, 16:13 UTC
- Message-ID
- <87o88obkb1.fsf@evledraar.gmail.com>
- In-Reply-To
- <YUZG0D5ayEWd7MLP@carlos-mbp.lan>
On Sat, Sep 18 2021, Carlo Marcelo Arenas Belón wrote:
Show 14 quoted lines
> My equivalent version for these fixes is obviously more verbose but IMHO > not that ugly (and as safe) > > It avoids the need to UNLEAK early by changing the program flow also for > the early return so the cleanup could be centralized in one single > function. > > Both, the cmdline and mailmap arrays (and the objects they accumulate) > are cleaned in a "reusable" way. > > Note that the cleaning of the "name" in the cmdline item throws a warning > as shown below which I intentionally didn't fix, as it would seem that > either the use of const there or the need to strdup is wrong. So hope > someone that knows this code better could chime in.
It should just be a "char *", I got that wrong in my version posted in the side-thread[1] & mentioned in the side-reply[2].
(I think I got it right in some earlier version days ago, it should be a 'char *' like anyting we malloc, but brainfart when re-doing/re-basing those changes).
Yours here below has a bug where you free() rev_cmdline_info items, you need to use release_revisions_cmdline_rev().
I should have said in [2], but thanks a lot to you and Andrzej for following up on the mess in t0000-basic.sh addressed by my v7 re-roll. It'll be really nice to get some of these leaks fixed & tested for.
I think I was rather curt in [2] after a long debugging session, just saying I appreciate it. Hopefully we can figure out some plan for mostly pulling in the same direction with regards to the way forward.
1. https://github.com/git/git/commit/06380cd4f56f4c542685eb7aa79e28285fe02c55 2. https://lore.kernel.org/git/87a6k8daeu.fsf@evledraar.gmail.com/
Show 97 quoted lines
> Carlo
> ------ >8 ------
> Subject: [PATCH] builtin/log: leaks from `git show` in t0000
>
> obviously not ready, since the following will need to be corrected:
>
> revision.c:1496:8: warning: passing 'const char *' to parameter of type 'void *' discards qualifiers [-Wincompatible-pointer-types-discards-qualifiers]
> free(info->rev[i].name);
> ^~~~~~~~~~~~~~~~~
>
> Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
> ---
> builtin/log.c | 8 ++++++--
> revision.c | 20 ++++++++++++++++++++
> revision.h | 5 +++++
> 3 files changed, 31 insertions(+), 2 deletions(-)
>
> diff --git a/builtin/log.c b/builtin/log.c
> index f75d87e8d7..1b1c1f53f4 100644
> --- a/builtin/log.c
> +++ b/builtin/log.c
> @@ -645,8 +645,10 @@ int cmd_show(int argc, const char **argv, const char *prefix)
> opt.tweak = show_setup_revisions_tweak;
> cmd_log_init(argc, argv, prefix, &rev, &opt);
>
> - if (!rev.no_walk)
> - return cmd_log_walk(&rev);
> + if (!rev.no_walk) {
> + ret = cmd_log_walk(&rev);
> + goto done;
> + }
>
> count = rev.pending.nr;
> objects = rev.pending.objects;
> @@ -702,6 +704,8 @@ int cmd_show(int argc, const char **argv, const char *prefix)
> }
> }
> free(objects);
> +done:
> + repo_clear_revisions(&rev);
> return ret;
> }
>
> diff --git a/revision.c b/revision.c
> index 0dabb5a0bc..ce62192dd8 100644
> --- a/revision.c
> +++ b/revision.c
> @@ -1487,6 +1487,18 @@ static void add_rev_cmdline(struct rev_info *revs,
> info->nr++;
> }
>
> +static void clear_rev_cmdline(struct rev_info *revs)
> +{
> + struct rev_cmdline_info *info = &revs->cmdline;
> + size_t i, nr = info->nr;
> +
> + for (i = 0; i < nr; i++)
> + free(info->rev[i].name);
> +
> + FREE_AND_NULL(info->rev);
> + info->nr = info->alloc = 0;
> +}
> +
> static void add_rev_cmdline_list(struct rev_info *revs,
> struct commit_list *commit_list,
> int whence,
> @@ -1845,6 +1857,14 @@ void repo_init_revisions(struct repository *r,
> init_display_notes(&revs->notes_opt);
> }
>
> +void repo_clear_revisions(struct rev_info *revs)
> +{
> + if (revs->mailmap)
> + clear_mailmap(revs->mailmap);
> + FREE_AND_NULL(revs->mailmap);
> + clear_rev_cmdline(revs);
> +}
> +
> static void add_pending_commit_list(struct rev_info *revs,
> struct commit_list *commit_list,
> unsigned int flags)
> diff --git a/revision.h b/revision.h
> index 0c65a760ee..f695c41cee 100644
> --- a/revision.h
> +++ b/revision.h
> @@ -358,6 +358,11 @@ void repo_init_revisions(struct repository *r,
> struct rev_info *revs,
> const char *prefix);
>
> +/*
> + * Free all structures dynamically allocated for the provided rev_info
> + */
> +void repo_clear_revisions(struct rev_info *revs);
> +
> /**
> * Parse revision information, filling in the `rev_info` structure, and
> * removing the used arguments from the argument list. Returns the number