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, 66 insertions, 0 deletions

diff --git a/sound/usb/midi.h b/sound/usb/midi.h
new file mode 100644
index 000000000..2100f1486
--- /dev/null
+++ b/sound/usb/midi.h
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __USBMIDI_H
+#define __USBMIDI_H
+
+/* maximum number of endpoints per interface */
+#define MIDI_MAX_ENDPOINTS 2
+
+/* data for QUIRK_MIDI_FIXED_ENDPOINT */
+struct snd_usb_midi_endpoint_info {
+	int8_t   out_ep;	/* ep number, 0 autodetect */
+	uint8_t  out_interval;	/* interval for interrupt endpoints */
+	int8_t   in_ep;
+	uint8_t  in_interval;
+	uint16_t out_cables;	/* bitmask */
+	uint16_t in_cables;	/* bitmask */
+	int16_t  assoc_in_jacks[16];
+	int16_t  assoc_out_jacks[16];
+};
+
+/* for QUIRK_MIDI_YAMAHA, data is NULL */
+
+/* for QUIRK_MIDI_MIDIMAN, data points to a snd_usb_midi_endpoint_info
+ * structure (out_cables and in_cables only) */
+
+/* for QUIRK_COMPOSITE, data points to an array of snd_usb_audio_quirk
+ * structures, terminated with .ifnum = -1 */
+
+/* for QUIRK_AUDIO_FIXED_ENDPOINT, data points to an audioformat structure */
+
+/* for QUIRK_AUDIO/MIDI_STANDARD_INTERFACE, data is NULL */
+
+/* for QUIRK_AUDIO_EDIROL_UA700_UA25/UA1000, data is NULL */
+
+/* for QUIRK_IGNORE_INTERFACE, data is NULL */
+
+/* for QUIRK_MIDI_NOVATION and _RAW, data is NULL */
+
+/* for QUIRK_MIDI_EMAGIC, data points to a snd_usb_midi_endpoint_info
+ * structure (out_cables and in_cables only) */
+
+/* for QUIRK_MIDI_CME, data is NULL */
+
+/* for QUIRK_MIDI_AKAI, data is NULL */
+
+int __snd_usbmidi_create(struct snd_card *card,
+			 struct usb_interface *iface,
+			 struct list_head *midi_list,
+			 const struct snd_usb_audio_quirk *quirk,
+			 unsigned int usb_id,
+			 unsigned int *num_rawmidis);
+
+static inline int snd_usbmidi_create(struct snd_card *card,
+		       struct usb_interface *iface,
+		       struct list_head *midi_list,
+		       const struct snd_usb_audio_quirk *quirk)
+{
+	return __snd_usbmidi_create(card, iface, midi_list, quirk, 0, NULL);
+}
+
+void snd_usbmidi_input_stop(struct list_head *p);
+void snd_usbmidi_input_start(struct list_head *p);
+void snd_usbmidi_disconnect(struct list_head *p);
+void snd_usbmidi_suspend(struct list_head *p);
+void snd_usbmidi_resume(struct list_head *p);
+
+#endif /* __USBMIDI_H */