[LTP] cve: reproducer for cve-2026-64600

[linuxtestproject.agent@gmail.com]

Hi Andrea,

On Fri, 24 Jul 2026, Andrea Cervesato wrote:
> cve: reproducer for cve-2026-64600

> diff --git a/testcases/kernel/fs/xfs/Makefile b/testcases/kernel/fs/xfs/Makefile
> new file mode 100644
> +top_srcdir			?= ../../../..
> +
> +include $(top_srcdir)/include/mk/testcases.mk
> +
> +LDLIBS			+= -lpthread
> +
> +include $(top_srcdir)/include/mk/generic_leaf_target.mk

Every existing standalone CVE reproducer named cve-<id>.c
(cve-2014-0196, cve-2016-7042, cve-2025-38236, cve-2026-46331, ...)
already lives under testcases/cve/, whose Makefile builds every
target from a wildcard and already carries per-target LDLIBS/CFLAGS
overrides (e.g. "-pthread" for other threaded reproducers), plus its
own .gitignore.

Is there a reason this one needs a brand-new
testcases/kernel/fs/xfs/ directory instead of adding
"cve-2026-64600: LDLIBS += -lpthread" to the existing
testcases/cve/Makefile?

Separately, this Makefile is also missing the
"SPDX-License-Identifier: GPL-2.0-or-later" + Copyright header that
every leaf Makefile is expected to start with.

> diff --git a/testcases/kernel/fs/xfs/cve-2026-64600.c b/testcases/kernel/fs/xfs/cve-2026-64600.c
> +	.filesystems = (struct tst_fs []) {
> +		{.type = "xfs"},
> +		{}
> +	},

testcases/kernel/syscalls/ioctl/ioctl_ficlone03.c's xfs entry sets
.min_kver = "4.16", .mkfs_ver = "mkfs.xfs >= 1.5.0" and .mkfs_opts =
{"-m", "reflink=1", NULL}, since reflink is only guaranteed once the
xfsprogs version/format enables it. Here the xfs entry has none of
that. On a system where mkfs.xfs does not default to reflink=1,
would setup() just TCONF through the EOPNOTSUPP/EINVAL/ENOSYS branch
instead of exercising the race, or is the plain default considered
reliable enough these days?

Verdict - Needs revision

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