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, 29 insertions, 0 deletions

diff --git a/drivers/dpll/zl3073x/flash.h b/drivers/dpll/zl3073x/flash.h
new file mode 100644
index 000000000..effe1b16b
--- /dev/null
+++ b/drivers/dpll/zl3073x/flash.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+
+#ifndef __ZL3073X_FLASH_H
+#define __ZL3073X_FLASH_H
+
+#include <linux/types.h>
+
+struct netlink_ext_ack;
+struct zl3073x_dev;
+
+int zl3073x_flash_mode_enter(struct zl3073x_dev *zldev, const void *util_ptr,
+			     size_t util_size, struct netlink_ext_ack *extack);
+
+int zl3073x_flash_mode_leave(struct zl3073x_dev *zldev,
+			     struct netlink_ext_ack *extack);
+
+int zl3073x_flash_page(struct zl3073x_dev *zldev, const char *component,
+		       u32 page, u32 addr, const void *data, size_t size,
+		       struct netlink_ext_ack *extack);
+
+int zl3073x_flash_page_copy(struct zl3073x_dev *zldev, const char *component,
+			    u32 src_page, u32 dst_page,
+			    struct netlink_ext_ack *extack);
+
+int zl3073x_flash_sectors(struct zl3073x_dev *zldev, const char *component,
+			  u32 page, u32 addr, const void *data, size_t size,
+			  struct netlink_ext_ack *extack);
+
+#endif /* __ZL3073X_FLASH_H */