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, 58 insertions, 0 deletions

diff --git a/io_uring/opdef.h b/io_uring/opdef.h
new file mode 100644
index 000000000..667f981e6
--- /dev/null
+++ b/io_uring/opdef.h
@@ -0,0 +1,58 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef IOU_OP_DEF_H
+#define IOU_OP_DEF_H
+
+struct io_uring_bpf_ctx;
+
+struct io_issue_def {
+	/* needs req->file assigned */
+	unsigned		needs_file : 1;
+	/* should block plug */
+	unsigned		plug : 1;
+	/* supports ioprio */
+	unsigned		ioprio : 1;
+	/* supports iopoll */
+	unsigned		iopoll : 1;
+	/* op supports buffer selection */
+	unsigned		buffer_select : 1;
+	/* hash wq insertion if file is a regular file */
+	unsigned		hash_reg_file : 1;
+	/* unbound wq insertion if file is a non-regular file */
+	unsigned		unbound_nonreg_file : 1;
+	/* set if opcode supports polled "wait" */
+	unsigned		pollin : 1;
+	unsigned		pollout : 1;
+	unsigned		poll_exclusive : 1;
+	/* skip auditing */
+	unsigned		audit_skip : 1;
+	/* vectored opcode, set if 1) vectored, and 2) handler needs to know */
+	unsigned		vectored : 1;
+	/* set to 1 if this opcode uses 128b sqes in a mixed sq */
+	unsigned		is_128 : 1;
+
+	/* size of async data needed, if any */
+	unsigned short		async_size;
+
+	/* bpf filter pdu size, if any */
+	unsigned short		filter_pdu_size;
+
+	int (*issue)(struct io_kiocb *, unsigned int);
+	int (*prep)(struct io_kiocb *, const struct io_uring_sqe *);
+	void (*filter_populate)(struct io_uring_bpf_ctx *, struct io_kiocb *);
+};
+
+struct io_cold_def {
+	const char		*name;
+
+	void (*sqe_copy)(struct io_kiocb *);
+	void (*cleanup)(struct io_kiocb *);
+	void (*fail)(struct io_kiocb *);
+};
+
+extern const struct io_issue_def io_issue_defs[];
+extern const struct io_cold_def io_cold_defs[];
+
+bool io_uring_op_supported(u8 opcode);
+
+void io_uring_optable_init(void);
+#endif