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, 45 insertions, 0 deletions

diff --git a/include/scsi/scsi_driver.h b/include/scsi/scsi_driver.h
new file mode 100644
index 000000000..249cea724
--- /dev/null
+++ b/include/scsi/scsi_driver.h
@@ -0,0 +1,45 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _SCSI_SCSI_DRIVER_H
+#define _SCSI_SCSI_DRIVER_H
+
+#include <linux/blk_types.h>
+#include <linux/device.h>
+#include <scsi/scsi_cmnd.h>
+
+struct module;
+struct request;
+
+struct scsi_driver {
+	struct device_driver	gendrv;
+
+	int (*probe)(struct scsi_device *);
+	void (*remove)(struct scsi_device *);
+	void (*shutdown)(struct scsi_device *);
+	int (*resume)(struct device *);
+	void (*rescan)(struct device *);
+	blk_status_t (*init_command)(struct scsi_cmnd *);
+	void (*uninit_command)(struct scsi_cmnd *);
+	int (*done)(struct scsi_cmnd *);
+	int (*eh_action)(struct scsi_cmnd *, int);
+	void (*eh_reset)(struct scsi_cmnd *);
+};
+#define to_scsi_driver(drv) \
+	container_of((drv), struct scsi_driver, gendrv)
+
+#define scsi_register_driver(drv) \
+	__scsi_register_driver(drv, THIS_MODULE)
+int __scsi_register_driver(struct scsi_driver *, struct module *);
+#define scsi_unregister_driver(drv) \
+	driver_unregister(&(drv)->gendrv);
+
+extern int scsi_register_interface(struct class_interface *);
+#define scsi_unregister_interface(intf) \
+	class_interface_unregister(intf)
+
+/* make sure not to use it with passthrough commands */
+static inline struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd)
+{
+	return to_scsi_driver(cmd->device->sdev_gendev.driver);
+}
+
+#endif /* _SCSI_SCSI_DRIVER_H */