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, 32 insertions, 0 deletions

diff --git a/drivers/acpi/sbshc.h b/drivers/acpi/sbshc.h
new file mode 100644
index 000000000..695c390e2
--- /dev/null
+++ b/drivers/acpi/sbshc.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+struct acpi_smb_hc;
+enum acpi_smb_protocol {
+	SMBUS_WRITE_QUICK = 2,
+	SMBUS_READ_QUICK = 3,
+	SMBUS_SEND_BYTE = 4,
+	SMBUS_RECEIVE_BYTE = 5,
+	SMBUS_WRITE_BYTE = 6,
+	SMBUS_READ_BYTE = 7,
+	SMBUS_WRITE_WORD  = 8,
+	SMBUS_READ_WORD  = 9,
+	SMBUS_WRITE_BLOCK = 0xa,
+	SMBUS_READ_BLOCK = 0xb,
+	SMBUS_PROCESS_CALL = 0xc,
+	SMBUS_BLOCK_PROCESS_CALL = 0xd,
+};
+
+enum acpi_sbs_device_addr {
+	ACPI_SBS_CHARGER = 0x9,
+	ACPI_SBS_MANAGER = 0xa,
+	ACPI_SBS_BATTERY = 0xb,
+};
+
+typedef void (*smbus_alarm_callback)(void *context);
+
+extern int acpi_smbus_read(struct acpi_smb_hc *hc, u8 protocol, u8 address,
+		u8 command, u8 *data);
+extern int acpi_smbus_write(struct acpi_smb_hc *hc, u8 protocol, u8 slave_address,
+		u8 command, u8 *data, u8 length);
+extern int acpi_smbus_register_callback(struct acpi_smb_hc *hc,
+		smbus_alarm_callback callback, void *context);
+extern int acpi_smbus_unregister_callback(struct acpi_smb_hc *hc);