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, 88 insertions, 0 deletions

diff --git a/scripts/genksyms/genksyms.h b/scripts/genksyms/genksyms.h
new file mode 100644
index 000000000..0c355075f
--- /dev/null
+++ b/scripts/genksyms/genksyms.h
@@ -0,0 +1,88 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* Generate kernel symbol version hashes.
+   Copyright 1996, 1997 Linux International.
+
+   New implementation contributed by Richard Henderson <rth@tamu.edu>
+   Based on original work by Bjorn Ekwall <bj0rn@blox.se>
+
+   This file is part of the Linux modutils.
+
+ */
+
+#ifndef MODUTILS_GENKSYMS_H
+#define MODUTILS_GENKSYMS_H 1
+
+#include <stdbool.h>
+#include <stdio.h>
+
+#include <list_types.h>
+
+enum symbol_type {
+	SYM_NORMAL, SYM_TYPEDEF, SYM_ENUM, SYM_STRUCT, SYM_UNION,
+	SYM_ENUM_CONST
+};
+
+enum symbol_status {
+	STATUS_UNCHANGED, STATUS_DEFINED, STATUS_MODIFIED
+};
+
+struct string_list {
+	struct string_list *next;
+	enum symbol_type tag;
+	int in_source_file;
+	char *string;
+};
+
+struct symbol {
+	struct hlist_node hnode;
+	char *name;
+	enum symbol_type type;
+	struct string_list *defn;
+	struct symbol *expansion_trail;
+	struct symbol *visited;
+	int is_extern;
+	int is_declared;
+	enum symbol_status status;
+	int is_override;
+};
+
+typedef struct string_list **yystype;
+#define YYSTYPE yystype
+
+extern int cur_line;
+extern char *cur_filename;
+extern int in_source_file;
+
+struct symbol *find_symbol(const char *name, enum symbol_type ns, int exact);
+struct symbol *add_symbol(const char *name, enum symbol_type type,
+			  struct string_list *defn, int is_extern);
+void export_symbol(const char *);
+
+void free_node(struct string_list *list);
+void free_list(struct string_list *s, struct string_list *e);
+struct string_list *copy_node(struct string_list *);
+struct string_list *copy_list_range(struct string_list *start,
+				    struct string_list *end);
+
+int yylex(void);
+int yyparse(void);
+
+extern bool dont_want_type_specifier;
+
+void error_with_pos(const char *, ...) __attribute__ ((format(printf, 1, 2)));
+
+/*----------------------------------------------------------------------*/
+#define xmalloc(size) ({ void *__ptr = malloc(size);		\
+	if(!__ptr && size != 0) {				\
+		fprintf(stderr, "out of memory\n");		\
+		exit(1);					\
+	}							\
+	__ptr; })
+#define xstrdup(str)  ({ char *__str = strdup(str);		\
+	if (!__str) {						\
+		fprintf(stderr, "out of memory\n");		\
+		exit(1);					\
+	}							\
+	__str; })
+
+#endif				/* genksyms.h */