bpf: mark a NULL kfunc argument precisegrafted

check_kfunc_arg() allows bpf_register_is_null() for nullable arguments
w/o marking the underlying scalar register precise. Hence a checkpoint
created on such a path would prune against arbitrary scalar value.

Fixes: 3bda08b63670 ("bpf: Allow NULL buffers in bpf_dynptr_slice(_rw)")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-5-0f5a360ff15d@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 49 insertions, 0 deletions

diff --git a/io_uring/poll.h b/io_uring/poll.h
new file mode 100644
index 000000000..5647c5138
--- /dev/null
+++ b/io_uring/poll.h
@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/io_uring_types.h>
+
+#define IO_POLL_ALLOC_CACHE_MAX 32
+
+enum {
+	IO_APOLL_OK,
+	IO_APOLL_ABORTED,
+	IO_APOLL_READY
+};
+
+struct io_poll {
+	struct file			*file;
+	struct wait_queue_head		*head;
+	__poll_t			events;
+	int				retries;
+	struct wait_queue_entry		wait;
+};
+
+struct async_poll {
+	struct io_poll		poll;
+	struct io_poll		*double_poll;
+};
+
+/*
+ * Must only be called inside issue_flags & IO_URING_F_MULTISHOT, or
+ * potentially other cases where we already "own" this poll request.
+ */
+static inline void io_poll_multishot_retry(struct io_kiocb *req)
+{
+	atomic_inc(&req->poll_refs);
+}
+
+int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
+int io_poll_add(struct io_kiocb *req, unsigned int issue_flags);
+
+int io_poll_remove_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
+int io_poll_remove(struct io_kiocb *req, unsigned int issue_flags);
+
+struct io_cancel_data;
+int io_poll_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd,
+		   unsigned issue_flags);
+int io_arm_apoll(struct io_kiocb *req, unsigned issue_flags, __poll_t mask);
+int io_arm_poll_handler(struct io_kiocb *req, unsigned issue_flags);
+bool io_poll_remove_all(struct io_ring_ctx *ctx, struct io_uring_task *tctx,
+			bool cancel_all);
+
+void io_poll_task_func(struct io_tw_req tw_req, io_tw_token_t tw);