In https://bugs.gentoo.org/719674#c12 gentoo sees nptl/tst-stack4 crashes somewhat reliably on arm64:

# while :; do date; env GCONV_PATH=/var/tmp/portage/sys-libs/glibc-2.30-r8/work/build-arm64-aarch64-unknown-linux-gnu-nptl/iconvdata LOCPATH=/var/tmp/portage/sys-libs/glibc-2.30-r8/work/build-arm64-aarch64-unknown-linux-gnu-nptl/localedata LC_ALL=C   /var/tmp/portage/sys-libs/glibc-2.30-r8/work/build-arm64-aarch64-unknown-linux-gnu-nptl/elf/ld-linux-aarch64.so.1 --library-path /var/tmp/portage/sys-libs/glibc-2.30-r8/work/build-arm64-aarch64-unknown-linux-gnu-nptl:/var/tmp/portage/sys-libs/glibc-2.30-r8/work/build-arm64-aarch64-unknown-linux-gnu-nptl/math:/var/tmp/portage/sys-libs/glibc-2.30-r8/work/build-arm64-aarch64-unknown-linux-gnu-nptl/elf:/var/tmp/portage/sys-libs/glibc-2.30-r8/work/build-arm64-aarch64-unknown-linux-gnu-nptl/dlfcn:/var/tmp/portage/sys-libs/glibc-2.30-r8/work/build-arm64-aarch64-unknown-linux-gnu-nptl/nss:/var/tmp/portage/sys-libs/glibc-2.30-r8/work/build-arm64-aarch64-unknown-linux-gnu-nptl/nis:/var/tmp/portage/sys-libs/glibc-2.30-r8/work/build-arm64-aarch64-unknown-linux-gnu-nptl/rt:/var/tmp/portage/sys-libs/glibc-2.30-r8/work/build-arm64-aarch64-unknown-linux-gnu-nptl/resolv:/var/tmp/portage/sys-libs/glibc-2.30-r8/work/build-arm64-aarch64-unknown-linux-gnu-nptl/mathvec:/var/tmp/portage/sys-libs/glibc-2.30-r8/work/build-arm64-aarch64-unknown-linux-gnu-nptl/support:/var/tmp/portage/sys-libs/glibc-2.30-r8/work/build-arm64-aarch64-unknown-linux-gnu-nptl/crypt:/var/tmp/portage/sys-libs/glibc-2.30-r8/work/build-arm64-aarch64-unknown-linux-gnu-nptl/nptl::/var/tmp/portage/sys-libs/glibc-2.30-r8/work/build-arm64-aarch64-unknown-linux-gnu-nptl//dlfcn /var/tmp/portage/sys-libs/glibc-2.30-r8/work/build-arm64-aarch64-unknown-linux-gnu-nptl/nptl/tst-stack4; done

Sun 03 May 2020 10:42:08 AM UTC
Sun 03 May 2020 10:42:21 AM UTC
Sun 03 May 2020 10:42:34 AM UTC
Didn't expect signal from child: got `Segmentation fault'
...
Sun 03 May 2020 10:42:56 AM UTC
malloc(): invalid size (unsorted)
Didn't expect signal from child: got `Aborted'
..
Sun 03 May 2020 10:46:21 AM UTC
free(): corrupted unsorted chunks
Didn't expect signal from child: got `Aborted'
...
Sun 03 May 2020 10:46:55 AM UTC
Didn't expect signal from child: got `Segmentation fault'
Sun 03 May 2020 10:47:04 AM UTC
double free or corruption (!prev)
Didn't expect signal from child: got `Aborted'
...
Sun 03 May 2020 10:50:54 AM UTC
free(): invalid pointer
Didn't expect signal from child: got `Aborted'
...
Sun 03 May 2020 10:52:12 AM UTC
tst-stack4: malloc.c:2379: sysmalloc: Assertion `(old_top == initial_top (av) && old_size == 0) || ((unsigned long) (old_size) >= MINSIZE && prev_inuse (old_top) && ((unsigned long) old_end & (pagesize - 1)) == 0)' failed.
Didn't expect signal from child: got `Aborted'

Does it look like the same issue described here?

# lscpu
Architecture:        aarch64
Byte Order:          Little Endian
CPU(s):              96
On-line CPU(s) list: 0-95
Thread(s) per core:  1
Core(s) per socket:  48
Socket(s):           2
Vendor ID:           Cavium
Model:               1
Model name:          ThunderX 88XX
Stepping:            0x1
BogoMIPS:            200.00
L1d cache:           32K
L1i cache:           78K
L2 cache:            16384K
Flags:               fp asimd evtstrm aes pmull sha1 sha2 crc32

# gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/aarch64-unknown-linux-gnu/9.3.0/lto-wrapper
Target: aarch64-unknown-linux-gnu
Configured with: /var/tmp/portage/sys-devel/gcc-9.3.0/work/gcc-9.3.0/configure --host=aarch64-unknown-linux-gnu --build=aarch64-unknown-linux-gnu --prefix=/usr --bindir=/usr/aarch64-unknown-linux-gnu/gcc-bin/9.3.0 --includedir=/usr/lib/gcc/aarch64-unknown-linux-gnu/9.3.0/include --datadir=/usr/share/gcc-data/aarch64-unknown-linux-gnu/9.3.0 --mandir=/usr/share/gcc-data/aarch64-unknown-linux-gnu/9.3.0/man --infodir=/usr/share/gcc-data/aarch64-unknown-linux-gnu/9.3.0/info --with-gxx-include-dir=/usr/lib/gcc/aarch64-unknown-linux-gnu/9.3.0/include/g++-v9 --with-python-dir=/share/gcc-data/aarch64-unknown-linux-gnu/9.3.0/python --enable-languages=c,c++,fortran --enable-obsolete --enable-secureplt --disable-werror --with-system-zlib --enable-nls --without-included-gettext --enable-checking=release --with-bugurl=https://bugs.gentoo.org/ --with-pkgversion='Gentoo 9.3.0 p2' --disable-esp --enable-libstdcxx-time --enable-shared --enable-threads=posix --enable-__cxa_atexit --enable-clocale=gnu --disable-multilib --disable-altivec --disable-fixed-point --enable-libgomp --disable-libmudflap --disable-libssp --disable-libada --disable-systemtap --enable-vtable-verify --enable-lto --without-isl --enable-default-pie --enable-default-ssp
Thread model: posix
gcc version 9.3.0 (Gentoo 9.3.0 p2)

# uname -r
4.9.0-4-arm64