selftests/bpf: Test rhtab kptr cancellation semanticsgrafted

Resizable hash-map updates and deletions must not perform full special-field
destruction in their caller context. In particular, a referenced kptr must
remain attached to the allocation until the memory allocator destructor can
release it safely.

Add separate coverage for both affected paths. The update test stores a task
kptr, replaces the ordinary value bytes with BPF_EXIST, and verifies that the
kptr survived. The delete test removes an element and exchanges its kptr
through the still-valid map-value pointer before the allocation is reclaimed.

Both cases observe a NULL kptr when rhtab uses bpf_obj_free_fields(). They
recover and release the reference after rhtab switches to cancellation
semantics.

Signed-off-by: Nuoqi Gui <gnq25@mails.tsinghua.edu.cn>
[ kkd: Split update and delete coverage and rewrote the commit log ]
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260904104203.345917-5-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 37 insertions, 0 deletions

diff --git a/tools/docs/check-variable-fonts.py b/tools/docs/check-variable-fonts.py
new file mode 100755
index 000000000..958d5a745
--- /dev/null
+++ b/tools/docs/check-variable-fonts.py
@@ -0,0 +1,37 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0-only
+# Copyright (C) Akira Yokosawa, 2024
+#
+# Ported to Python by (c) Mauro Carvalho Chehab, 2025
+#
+# pylint: disable=C0103
+
+"""
+Detect problematic Noto CJK variable fonts.
+
+or more details, see .../tools/lib/python/kdoc/latex_fonts.py.
+"""
+
+import argparse
+import sys
+import os.path
+
+src_dir = os.path.dirname(os.path.realpath(__file__))
+sys.path.insert(0, os.path.join(src_dir, '../lib/python'))
+
+from kdoc.latex_fonts import LatexFontChecker
+
+checker = LatexFontChecker()
+
+parser=argparse.ArgumentParser(description=checker.description(),
+                               formatter_class=argparse.RawTextHelpFormatter)
+parser.add_argument("--deny-vf",
+                    help="XDG_CONFIG_HOME dir containing fontconfig/fonts.conf file")
+
+args=parser.parse_args()
+
+msg = LatexFontChecker(args.deny_vf).check()
+if msg:
+    print(msg)
+
+sys.exit(1)