Re: glibc 2.36 build failure on Fedora 36 with gcc 12 (-Werror=use-after-free)

[Sunil Pandey <skpgkp2@gmail.com>]

On Fri, Jul 29, 2022 at 10:52 AM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> On Fri, Jul 29, 2022 at 10:47 AM Sunil Pandey <skpgkp2@gmail.com> wrote:
> >
> > On Fri, Jul 29, 2022 at 9:08 AM Sunil Pandey <skpgkp2@gmail.com> wrote:
> > >
> > > On Fri, Jul 29, 2022 at 8:43 AM Sunil Pandey <skpgkp2@gmail.com> wrote:
> > > >
> > > > On Fri, Jul 29, 2022 at 8:26 AM Carlos O'Donell via Libc-alpha
> > > > <libc-alpha@sourceware.org> wrote:
> > > > >
> > > > > Just posting here for the record that I see a glibc 2.36 build failure
> > > > > with Fedora 36 and gcc 12.
> > > > >
> > > > > localealias.c: In function ‘read_alias_file’:
> > > > > localealias.c:335:56: error: pointer may be used after ‘realloc’ [-Werror=use-after-free]
> > > > >   335 |                               map[i].alias += new_pool - string_space;
> > > > >       |                                               ~~~~~~~~~^~~~~~~~~~~~~~
> > > > > localealias.c:325:49: note: call to ‘realloc’ here
> > > > >   325 |                       char *new_pool = (char *) realloc (string_space, new_size);
> > > > >       |                                                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > > > > cc1: all warnings being treated as errors
> > > > >
> > > > > I'm going to review this quickly before we make the glibc release.
> > > > >
> > > > > --
> > > > > Cheers,
> > > > > Carlos.
> > > > >
> > > >
> > > > I am getting these 2 wide string test failures on my SKX server.
> > > >
> > > > FAIL: wcsmbs/test-c8rtomb (Not reproducible)
> > > >
> > > > FAIL: wcsmbs/test-mbrtoc8
> > > >
> > > > $ wcsmbs/test-mbrtoc8
> > > > test-mbrtoc8.c:477: numeric comparison failure
> > > >    left: 2 (0x2); from: mbrtoc8 (buf, mbs, 1, &s)
> > > >   right: 1 (0x1); from: (size_t) 1
> > > > test-mbrtoc8.c:479: numeric comparison failure
> > > >    left: 0 (0x0); from: buf[0]
> > > >   right: 195 (0xc3); from: 0xC3
> > > > test-mbrtoc8.c:481: numeric comparison failure
> > > >    left: 204 (0xcc); from: buf[0]
> > > >   right: 138 (0x8a); from: 0x8A
> > > > test-mbrtoc8.c:483: numeric comparison failure
> > > >    left: 132 (0x84); from: buf[0]
> > > >   right: 204 (0xcc); from: 0xCC
> > > > test-mbrtoc8.c:484: numeric comparison failure
> > > >    left: 0 (0x0); from: mbrtoc8 (buf, mbs, 1, &s)
> > > >   right: 18446744073709551613 (0xfffffffffffffffd); from: (size_t) -3
> > > > test-mbrtoc8.c:485: numeric comparison failure
> > > >    left: 0 (0x0); from: buf[0]
> > > >   right: 132 (0x84); from: 0x84
> > > > test-mbrtoc8.c:516: numeric comparison failure
> > > >    left: 2 (0x2); from: mbrtoc8 (buf, mbs, 1, &s)
> > > >   right: 1 (0x1); from: (size_t) 1
> > > > test-mbrtoc8.c:518: numeric comparison failure
> > > >    left: 0 (0x0); from: buf[0]
> > > >   right: 195 (0xc3); from: 0xC3
> > > > test-mbrtoc8.c:520: numeric comparison failure
> > > >    left: 204 (0xcc); from: buf[0]
> > > >   right: 170 (0xaa); from: 0xAA
> > > > test-mbrtoc8.c:522: numeric comparison failure
> > > >    left: 140 (0x8c); from: buf[0]
> > > >   right: 204 (0xcc); from: 0xCC
> > > > test-mbrtoc8.c:523: numeric comparison failure
> > > >    left: 0 (0x0); from: mbrtoc8 (buf, mbs, 1, &s)
> > > >   right: 18446744073709551613 (0xfffffffffffffffd); from: (size_t) -3
> > > > test-mbrtoc8.c:524: numeric comparison failure
> > > >    left: 0 (0x0); from: buf[0]
> > > >   right: 140 (0x8c); from: 0x8C
> > > > error: 12 test failures
> > >
> > > These 2 tests fail on their first commit itself, unless this issue
> > > is specific to my machine.
> > >
> > > commit f4fe72a4f7b22588a7c902e39ddd3dcd244bbf9f (HEAD)
> > > Author: Tom Honermann <tom@honermann.net>
> > > Date:   Thu Jun 30 08:52:15 2022 -0400
> > >
> > >     stdlib: Tests for mbrtoc8, c8rtomb, and the char8_t typedef.
> >
> > Steps to reproduce:
> >
> > make glibc
> > make check subdirs=wcsmbs -j40
>
> This patch should fix it:
>
> https://sourceware.org/pipermail/libc-alpha/2022-July/141144.html
>
> --
> H.J.

It fixes the issue.

--Sunil