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, 218 insertions, 0 deletions

diff --git a/drivers/bluetooth/hci_uart.h b/drivers/bluetooth/hci_uart.h
new file mode 100644
index 000000000..48ac7ca93
--- /dev/null
+++ b/drivers/bluetooth/hci_uart.h
@@ -0,0 +1,218 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ *
+ *  Bluetooth HCI UART driver
+ *
+ *  Copyright (C) 2000-2001  Qualcomm Incorporated
+ *  Copyright (C) 2002-2003  Maxim Krasnyansky <maxk@qualcomm.com>
+ *  Copyright (C) 2004-2005  Marcel Holtmann <marcel@holtmann.org>
+ */
+
+#ifndef N_HCI
+#define N_HCI	15
+#endif
+
+/* Ioctls */
+#define HCIUARTSETPROTO		_IOW('U', 200, int)
+#define HCIUARTGETPROTO		_IOR('U', 201, int)
+#define HCIUARTGETDEVICE	_IOR('U', 202, int)
+#define HCIUARTSETFLAGS		_IOW('U', 203, int)
+#define HCIUARTGETFLAGS		_IOR('U', 204, int)
+
+/* UART protocols */
+#define HCI_UART_MAX_PROTO	13
+
+#define HCI_UART_H4	0
+#define HCI_UART_BCSP	1
+#define HCI_UART_3WIRE	2
+#define HCI_UART_H4DS	3
+#define HCI_UART_LL	4
+#define HCI_UART_ATH3K	5
+#define HCI_UART_INTEL	6
+#define HCI_UART_BCM	7
+#define HCI_UART_QCA	8
+#define HCI_UART_AG6XX	9
+#define HCI_UART_NOKIA	10
+#define HCI_UART_MRVL	11
+#define HCI_UART_AML	12
+
+#define HCI_UART_RAW_DEVICE	0
+#define HCI_UART_RESET_ON_INIT	1
+#define HCI_UART_INIT_PENDING	3
+#define HCI_UART_EXT_CONFIG	4
+#define HCI_UART_VND_DETECT	5
+
+struct hci_uart;
+struct serdev_device;
+
+struct hci_uart_proto {
+	unsigned int id;
+	const char *name;
+	unsigned int manufacturer;
+	unsigned int init_speed;
+	unsigned int oper_speed;
+	int (*open)(struct hci_uart *hu);
+	int (*close)(struct hci_uart *hu);
+	int (*flush)(struct hci_uart *hu);
+	int (*setup)(struct hci_uart *hu);
+	int (*set_baudrate)(struct hci_uart *hu, unsigned int speed);
+	int (*recv)(struct hci_uart *hu, const void *data, int len);
+	int (*enqueue)(struct hci_uart *hu, struct sk_buff *skb);
+	struct sk_buff *(*dequeue)(struct hci_uart *hu);
+};
+
+struct hci_uart {
+	struct tty_struct	*tty;
+	struct serdev_device	*serdev;
+	struct hci_dev		*hdev;
+	unsigned long		flags;
+	unsigned long		hdev_flags;
+
+	struct work_struct	init_ready;
+	struct work_struct	write_work;
+
+	const struct hci_uart_proto *proto;
+	struct percpu_rw_semaphore proto_lock;	/* Stop work for proto close */
+	void			*priv;
+
+	struct sk_buff		*tx_skb;
+	unsigned long		tx_state;
+
+	unsigned int init_speed;
+	unsigned int oper_speed;
+
+	u8			alignment;
+	u8			padding;
+};
+
+/* HCI_UART proto flag bits */
+#define HCI_UART_PROTO_SET		0
+#define HCI_UART_REGISTERED		1
+#define HCI_UART_PROTO_READY		2
+#define HCI_UART_NO_SUSPEND_NOTIFIER	3
+#define HCI_UART_PROTO_INIT		4
+
+/* TX states  */
+#define HCI_UART_SENDING	1
+#define HCI_UART_TX_WAKEUP	2
+
+int hci_uart_register_proto(const struct hci_uart_proto *p);
+int hci_uart_unregister_proto(const struct hci_uart_proto *p);
+
+int hci_uart_register_device_priv(struct hci_uart *hu,
+				  const struct hci_uart_proto *p,
+				  int sizeof_priv);
+
+static inline int hci_uart_register_device(struct hci_uart *hu,
+					   const struct hci_uart_proto *p)
+{
+	return hci_uart_register_device_priv(hu, p, 0);
+}
+
+void hci_uart_unregister_device(struct hci_uart *hu);
+
+int hci_uart_tx_wakeup(struct hci_uart *hu);
+int hci_uart_wait_until_sent(struct hci_uart *hu);
+int hci_uart_init_ready(struct hci_uart *hu);
+void hci_uart_init_work(struct work_struct *work);
+void hci_uart_set_baudrate(struct hci_uart *hu, unsigned int speed);
+bool hci_uart_has_flow_control(struct hci_uart *hu);
+void hci_uart_set_flow_control(struct hci_uart *hu, bool enable);
+void hci_uart_set_speeds(struct hci_uart *hu, unsigned int init_speed,
+			 unsigned int oper_speed);
+
+struct h4_recv_pkt {
+	u8  type;	/* Packet type */
+	u8  hlen;	/* Header length */
+	u8  loff;	/* Data length offset in header */
+	u8  lsize;	/* Data length field size */
+	u16 maxlen;	/* Max overall packet length */
+	int (*recv)(struct hci_dev *hdev, struct sk_buff *skb);
+};
+
+#define H4_RECV_ACL \
+	.type = HCI_ACLDATA_PKT, \
+	.hlen = HCI_ACL_HDR_SIZE, \
+	.loff = 2, \
+	.lsize = 2, \
+	.maxlen = HCI_MAX_FRAME_SIZE \
+
+#define H4_RECV_SCO \
+	.type = HCI_SCODATA_PKT, \
+	.hlen = HCI_SCO_HDR_SIZE, \
+	.loff = 2, \
+	.lsize = 1, \
+	.maxlen = HCI_MAX_SCO_SIZE
+
+#define H4_RECV_EVENT \
+	.type = HCI_EVENT_PKT, \
+	.hlen = HCI_EVENT_HDR_SIZE, \
+	.loff = 1, \
+	.lsize = 1, \
+	.maxlen = HCI_MAX_EVENT_SIZE
+
+#define H4_RECV_ISO \
+	.type = HCI_ISODATA_PKT, \
+	.hlen = HCI_ISO_HDR_SIZE, \
+	.loff = 2, \
+	.lsize = 2, \
+	.maxlen = HCI_MAX_FRAME_SIZE \
+
+#ifdef CONFIG_BT_HCIUART_H4
+int h4_init(void);
+int h4_deinit(void);
+
+struct sk_buff *h4_recv_buf(struct hci_uart *hu, struct sk_buff *skb,
+			    const unsigned char *buffer, int count,
+			    const struct h4_recv_pkt *pkts, int pkts_count);
+#endif
+
+#ifdef CONFIG_BT_HCIUART_BCSP
+int bcsp_init(void);
+int bcsp_deinit(void);
+#endif
+
+#ifdef CONFIG_BT_HCIUART_LL
+int ll_init(void);
+int ll_deinit(void);
+#endif
+
+#ifdef CONFIG_BT_HCIUART_ATH3K
+int ath_init(void);
+int ath_deinit(void);
+#endif
+
+#ifdef CONFIG_BT_HCIUART_3WIRE
+int h5_init(void);
+int h5_deinit(void);
+#endif
+
+#ifdef CONFIG_BT_HCIUART_INTEL
+int intel_init(void);
+int intel_deinit(void);
+#endif
+
+#ifdef CONFIG_BT_HCIUART_BCM
+int bcm_init(void);
+int bcm_deinit(void);
+#endif
+
+#ifdef CONFIG_BT_HCIUART_QCA
+int qca_init(void);
+int qca_deinit(void);
+#endif
+
+#ifdef CONFIG_BT_HCIUART_AG6XX
+int ag6xx_init(void);
+int ag6xx_deinit(void);
+#endif
+
+#ifdef CONFIG_BT_HCIUART_MRVL
+int mrvl_init(void);
+int mrvl_deinit(void);
+#endif
+
+#ifdef CONFIG_BT_HCIUART_AML
+int aml_init(void);
+int aml_deinit(void);
+#endif