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, 68 insertions, 0 deletions

diff --git a/fs/isofs/joliet.c b/fs/isofs/joliet.c
new file mode 100644
index 000000000..c0f04a1e7
--- /dev/null
+++ b/fs/isofs/joliet.c
@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/isofs/joliet.c
+ *
+ *  (C) 1996 Gordon Chaffee
+ *
+ *  Joliet: Microsoft's Unicode extensions to iso9660
+ */
+
+#include <linux/types.h>
+#include <linux/nls.h>
+#include "isofs.h"
+
+/*
+ * Convert Unicode 16 to UTF-8 or ASCII.
+ */
+static int
+uni16_to_x8(unsigned char *ascii, __be16 *uni, int len, struct nls_table *nls)
+{
+	__be16 *ip, ch;
+	unsigned char *op;
+
+	ip = uni;
+	op = ascii;
+
+	while ((ch = get_unaligned(ip)) && len) {
+		int llen;
+		llen = nls->uni2char(be16_to_cpu(ch), op, NLS_MAX_CHARSET_SIZE);
+		if (llen > 0)
+			op += llen;
+		else
+			*op++ = '?';
+		ip++;
+
+		len--;
+	}
+	*op = 0;
+	return (op - ascii);
+}
+
+int
+get_joliet_filename(struct iso_directory_record * de, unsigned char *outname, struct inode * inode)
+{
+	struct nls_table *nls;
+	unsigned char len = 0;
+
+	nls = ISOFS_SB(inode->i_sb)->s_nls_iocharset;
+
+	if (!nls) {
+		len = utf16s_to_utf8s((const wchar_t *) de->name,
+				de->name_len[0] >> 1, UTF16_BIG_ENDIAN,
+				outname, PAGE_SIZE);
+	} else {
+		len = uni16_to_x8(outname, (__be16 *) de->name,
+				de->name_len[0] >> 1, nls);
+	}
+	if ((len > 2) && (outname[len-2] == ';') && (outname[len-1] == '1'))
+		len -= 2;
+
+	/*
+	 * Windows doesn't like periods at the end of a name,
+	 * so neither do we
+	 */
+	while (len >= 2 && (outname[len-1] == '.'))
+		len--;
+
+	return len;
+}