On Tue, Oct 19 2021, Jeff King wrote:
> On Tue, Oct 19, 2021 at 06:18:40PM -0400, Jeff King wrote:
>
>> > @@ -86,8 +86,6 @@ int cmd_ls_remote(int argc, const char **argv, const char *prefix)
>> >
>> > packet_trace_identity("ls-remote");
>> >
>> > - UNLEAK(sorting);
>> > -
>> > if (argc > 1) {
>> > int i;
>> > CALLOC_ARRAY(pattern, argc);
>> > @@ -139,8 +137,13 @@ int cmd_ls_remote(int argc, const char **argv, const char *prefix)
>> > item->symref = xstrdup_or_null(ref->symref);
>> > }
>> >
>> > - if (sorting)
>> > + if (sorting_options.nr) {
>> > + struct ref_sorting *sorting;
>> > + UNLEAK(sorting);
>> > +
>> > + sorting = ref_sorting_options(&sorting_options);
>> > ref_array_sort(sorting, &ref_array);
>> > + }
>>
>> I wondered at first about pulling this UNLEAK() down, but it's because
>> you move the "sorting" variable itself into the smaller scope. So this
>> makes sense (and calling UNLEAK() before the pointer is set is perfectly
>> fine, since it takes the address of the auto variable). It is a shame
>> you can't just ref_sorting_free() afterwards, but we don't have that
>> function yet. And adding it is way out of scope here. :)
>
> Actually, I think I was wrong here. UNLEAK() will look at &sorting, but
> it will snapshot its data at the time of the call. So it won't do
> anything when the variable doesn't yet have a value.
>
> You can demonstrate with:
>
> $ make SANITIZE=leak
> $ ./git ls-remote --sort=refname .
>
> which will complain. Bumping it down like this:
>
> diff --git a/builtin/ls-remote.c b/builtin/ls-remote.c
> index 1e6017cdaa..a94a220256 100644
> --- a/builtin/ls-remote.c
> +++ b/builtin/ls-remote.c
> @@ -139,10 +139,10 @@ int cmd_ls_remote(int argc, const char **argv, const char *prefix)
>
> if (sorting_options.nr) {
> struct ref_sorting *sorting;
> - UNLEAK(sorting);
>
> sorting = ref_sorting_options(&sorting_options);
> ref_array_sort(sorting, &ref_array);
> + UNLEAK(sorting);
> }
>
> for (i = 0; i < ref_array.nr; i++) {
>
> clears it up. Note that there are other similar "leaks" (e.g., if you
> give a pattern in argv[1]) which should be punted to another topic, but
> I think you'd want to deal with this one since you're moving the
> UNLEAK() around.
>
> -Peff
With or without your change Junio's patch still makes t0016-oidmap.sh
fail when applied on top of master under SANITIZE=leak, it passed
before:
=================================================================
==3448774==ERROR: LeakSanitizer: detected memory leaks
Direct leak of 16 byte(s) in 1 object(s) allocated from:
#0 0x7ff5c1c8ab45 in __interceptor_calloc ../../../../src/libsanitizer/lsan/lsan_interceptors.cpp:76
#1 0x5614d26ac4e5 in xcalloc /home/avar/g/git/wrapper.c:140
#2 0x5614d26186b0 in ref_default_sorting /home/avar/g/git/ref-filter.c:2676
#3 0x5614d26187c9 in ref_sorting_options /home/avar/g/git/ref-filter.c:2707
#4 0x5614d24e21c3 in cmd_tag builtin/tag.c:527
#5 0x5614d2407a89 in run_builtin /home/avar/g/git/git.c:461
#6 0x5614d2407e98 in handle_builtin /home/avar/g/git/git.c:713
#7 0x5614d2408105 in run_argv /home/avar/g/git/git.c:780
#8 0x5614d24085ae in cmd_main /home/avar/g/git/git.c:911
#9 0x5614d24ef3d8 in main /home/avar/g/git/common-main.c:52
#10 0x7ff5c1a06d09 in __libc_start_main ../csu/libc-start.c:308
I.e. the leak from ref_sorting_options() via ref_default_sorting() is
new in this commit for those codepaths.
