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, 43 insertions, 0 deletions

diff --git a/fs/jffs2/acl.h b/fs/jffs2/acl.h
new file mode 100644
index 000000000..e976b8cb8
--- /dev/null
+++ b/fs/jffs2/acl.h
@@ -0,0 +1,43 @@
+/*
+ * JFFS2 -- Journalling Flash File System, Version 2.
+ *
+ * Copyright © 2006  NEC Corporation
+ *
+ * Created by KaiGai Kohei <kaigai@ak.jp.nec.com>
+ *
+ * For licensing information, see the file 'LICENCE' in this directory.
+ *
+ */
+
+struct jffs2_acl_entry {
+	jint16_t	e_tag;
+	jint16_t	e_perm;
+	jint32_t	e_id;
+};
+
+struct jffs2_acl_entry_short {
+	jint16_t	e_tag;
+	jint16_t	e_perm;
+};
+
+struct jffs2_acl_header {
+	jint32_t	a_version;
+	struct jffs2_acl_entry	a_entries[];
+};
+
+#ifdef CONFIG_JFFS2_FS_POSIX_ACL
+
+struct posix_acl *jffs2_get_acl(struct inode *inode, int type, bool rcu);
+int jffs2_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
+		  struct posix_acl *acl, int type);
+extern int jffs2_init_acl_pre(struct inode *, struct inode *, umode_t *);
+extern int jffs2_init_acl_post(struct inode *);
+
+#else
+
+#define jffs2_get_acl				(NULL)
+#define jffs2_set_acl				(NULL)
+#define jffs2_init_acl_pre(dir_i,inode,mode)	(0)
+#define jffs2_init_acl_post(inode)		(0)
+
+#endif	/* CONFIG_JFFS2_FS_POSIX_ACL */