selftests/bpf: Reject graph kptr use after RCU unlockgrafted

Add a sleepable verifier test that loads a graph-node local kptr in an
explicit RCU read-side critical section, then passes its node to
bpf_rbtree_remove() after the section ends.

Before the verifier fix, the stale NON_OWN_REF flag makes the node look like
a live borrowed reference and the program is accepted. After the fix, the
pointer is demoted without NON_OWN_REF and the graph kfunc argument is
rejected.

Also exercise a graph kptr loaded while a spin lock provides implicit RCU
protection. The pointer must be invalidated when the lock is released, which
guards the required ordering between non-owning-reference invalidation and
RCU demotion.

Update the existing fault-protected load test state description. The
post-unlock pointer no longer carries NON_OWN_REF, but remains readable
because the load is rewritten to use BPF_PROBE_MEM.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 85 insertions, 0 deletions

diff --git a/scripts/genksyms/keywords.c b/scripts/genksyms/keywords.c
new file mode 100644
index 000000000..ee1499d27
--- /dev/null
+++ b/scripts/genksyms/keywords.c
@@ -0,0 +1,85 @@
+// SPDX-License-Identifier: GPL-2.0-only
+static struct resword {
+	const char *name;
+	int token;
+} keywords[] = {
+	{ "__GENKSYMS_EXPORT_SYMBOL", EXPORT_SYMBOL_KEYW },
+	{ "__asm", ASM_KEYW },
+	{ "__asm__", ASM_KEYW },
+	{ "__attribute", ATTRIBUTE_KEYW },
+	{ "__attribute__", ATTRIBUTE_KEYW },
+	{ "__const", CONST_KEYW },
+	{ "__const__", CONST_KEYW },
+	{ "__extension__", EXTENSION_KEYW },
+	{ "__inline", INLINE_KEYW },
+	{ "__inline__", INLINE_KEYW },
+	{ "__signed", SIGNED_KEYW },
+	{ "__signed__", SIGNED_KEYW },
+	{ "__typeof", TYPEOF_KEYW },
+	{ "__typeof__", TYPEOF_KEYW },
+	{ "__typeof_unqual", TYPEOF_KEYW },
+	{ "__typeof_unqual__", TYPEOF_KEYW },
+	{ "__volatile", VOLATILE_KEYW },
+	{ "__volatile__", VOLATILE_KEYW },
+	{ "__builtin_va_list", VA_LIST_KEYW },
+
+	{ "__int128", BUILTIN_INT_KEYW },
+	{ "__int128_t", BUILTIN_INT_KEYW },
+	{ "__uint128_t", BUILTIN_INT_KEYW },
+
+	// According to rth, c99 defines "_Bool", "__restrict", "__restrict__", "restrict".  KAO
+	{ "_Bool", BOOL_KEYW },
+	{ "__restrict", RESTRICT_KEYW },
+	{ "__restrict__", RESTRICT_KEYW },
+	{ "restrict", RESTRICT_KEYW },
+	{ "asm", ASM_KEYW },
+
+	// c11 keywords that can be used at module scope
+	{ "_Static_assert", STATIC_ASSERT_KEYW },
+
+	// attribute commented out in modutils 2.4.2.  People are using 'attribute' as a
+	// field name which breaks the genksyms parser.  It is not a gcc keyword anyway.
+	// KAO. },
+	// { "attribute", ATTRIBUTE_KEYW },
+
+	// X86 named address space qualifiers
+	{ "__seg_gs", X86_SEG_KEYW },
+	{ "__seg_fs", X86_SEG_KEYW },
+
+	{ "auto", AUTO_KEYW },
+	{ "char", CHAR_KEYW },
+	{ "const", CONST_KEYW },
+	{ "double", DOUBLE_KEYW },
+	{ "enum", ENUM_KEYW },
+	{ "extern", EXTERN_KEYW },
+	{ "float", FLOAT_KEYW },
+	{ "inline", INLINE_KEYW },
+	{ "int", INT_KEYW },
+	{ "long", LONG_KEYW },
+	{ "register", REGISTER_KEYW },
+	{ "short", SHORT_KEYW },
+	{ "signed", SIGNED_KEYW },
+	{ "static", STATIC_KEYW },
+	{ "struct", STRUCT_KEYW },
+	{ "typedef", TYPEDEF_KEYW },
+	{ "typeof", TYPEOF_KEYW },
+	{ "typeof_unqual", TYPEOF_KEYW },
+	{ "union", UNION_KEYW },
+	{ "unsigned", UNSIGNED_KEYW },
+	{ "void", VOID_KEYW },
+	{ "volatile", VOLATILE_KEYW },
+};
+
+#define NR_KEYWORDS (sizeof(keywords)/sizeof(struct resword))
+
+static int is_reserved_word(register const char *str, register unsigned int len)
+{
+	int i;
+	for (i = 0; i < NR_KEYWORDS; i++) {
+		struct resword *r = keywords + i;
+		int l = strlen(r->name);
+		if (len == l && !memcmp(str, r->name, len))
+			return r->token;
+	}
+	return -1;
+}