LeakSanitizer reporting leak issue from Configure [ithread & clang]

[atoomic]

I confirmed that this is an issue with at least the following tags:

• v5.18.1
• v5.26.0
• v5.28.1
• v5.30.0
• v5.32.0
• v5.33.1

You can see the leak when running the following command:

> git clean -dxf; ./Configure -Dusedevel -des -Dcc="ccache clang" -Accflags="-Werror=declaration-after-statement -g -fno-omit-frame-pointer -fsanitize=address  -fno-common -fsanitize-blacklist=`pwd`/asan_ignore" -Aldflags="-fsanitize=address" -Duseithreads

Note: I used Fedora 32 x86_64 to reproduce the issue

Extract from the Configure output

...
lgamma_r() found.
Checking to see if your libm supports _LIB_VERSION...
No, it does not (probably harmless)
link() found.
llrint() found.
llrintl() found.
llround() found.
llroundl() found.
localeconv_l() NOT found.
localtime_r() found.

=================================================================
==328778==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 16 byte(s) in 1 object(s) allocated from:
    #0 0x4bd27f  (/home/atoomic/workspace/perl/UU/try+0x4bd27f)
    #1 0x4f25a9  (/home/atoomic/workspace/perl/UU/try+0x4f25a9)
    #2 0x7fbbea8c6041  (/lib64/libc.so.6+0x27041)

SUMMARY: AddressSanitizer: 16 byte(s) leaked in 1 allocation(s).
lockf() found.
log1p() found.
log2() found.
logb() found.
...

also view: #18012 and #18054

[richardleach]

Looks like the block at https://github.com/Perl/perl5/blob/blead/Configure#L16053. Adding explicit free()s seems to work:

int main()
{
    int result = 0;
    time_t t = time(0L);
    char w_tz[]="TZ" "=GMT+5",
	 e_tz[]="TZ" "=GMT-5",
	*tz_e = (char*)malloc(16),
	*tz_w = (char*)malloc(16);
    struct tm tm_e, tm_w;
    memset(&tm_e,'\0',sizeof(struct tm));
    memset(&tm_w,'\0',sizeof(struct tm));
    strcpy(tz_e,e_tz);
    strcpy(tz_w,w_tz);

    putenv(tz_e);
    localtime_r(&t, &tm_e);

    putenv(tz_w);
    localtime_r(&t, &tm_w);

    if( memcmp(&tm_e, &tm_w, sizeof(struct tm)) == 0 )
	result = 1;

    free(tz_e);free(tz_w);
    return result;
}

[richardleach]

Fixed with bb05203?

[atoomic]

I can confirm that the issue described here is fixed by commit bb05203
thanks @richardleach and @Tux