selftests/bpf: Add a test for objects stuck in free_by_rcu_ttracegrafted

Delete all elements of BPF_F_NO_PREALLOC hash map in one batch. The first
free_bulk() starts RCU tasks trace GP and the rest of the elements are
freed while it's in flight. Wait for call_rcu_ttrace_in_progress to clear
in bpf_mem_cache of every cpu and check that free_by_rcu_ttrace and
waiting_for_gp_ttrace lists are empty.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20260930095920.601738-4-alexei.starovoitov@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

1 files changed, 177 insertions, 0 deletions

diff --git a/drivers/usb/serial/omninet.c b/drivers/usb/serial/omninet.c
new file mode 100644
index 000000000..363b8432c
--- /dev/null
+++ b/drivers/usb/serial/omninet.c
@@ -0,0 +1,177 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * USB ZyXEL omni.net driver
+ *
+ * Copyright (C) 2013,2017 Johan Hovold <johan@kernel.org>
+ *
+ * See Documentation/usb/usb-serial.rst for more information on using this
+ * driver
+ *
+ * Please report both successes and troubles to the author at omninet@kroah.com
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+#include <linux/usb/serial.h>
+
+#define DRIVER_AUTHOR "Alessandro Zummo"
+#define DRIVER_DESC "USB ZyXEL omni.net Driver"
+
+#define ZYXEL_VENDOR_ID		0x0586
+#define ZYXEL_OMNINET_ID	0x1000
+#define ZYXEL_OMNI_56K_PLUS_ID	0x1500
+/* This one seems to be a re-branded ZyXEL device */
+#define BT_IGNITIONPRO_ID	0x2000
+
+#define OMNINET_HEADERLEN	4
+#define OMNINET_BULKOUTSIZE	64
+#define OMNINET_PAYLOADSIZE	(OMNINET_BULKOUTSIZE - OMNINET_HEADERLEN)
+
+/* function prototypes */
+static void omninet_process_read_urb(struct urb *urb);
+static int omninet_prepare_write_buffer(struct usb_serial_port *port,
+				void *buf, size_t count);
+static int omninet_calc_num_ports(struct usb_serial *serial,
+				struct usb_serial_endpoints *epds);
+static int omninet_port_probe(struct usb_serial_port *port);
+static void omninet_port_remove(struct usb_serial_port *port);
+
+static const struct usb_device_id id_table[] = {
+	{ USB_DEVICE(ZYXEL_VENDOR_ID, ZYXEL_OMNINET_ID) },
+	{ USB_DEVICE(ZYXEL_VENDOR_ID, ZYXEL_OMNI_56K_PLUS_ID) },
+	{ USB_DEVICE(ZYXEL_VENDOR_ID, BT_IGNITIONPRO_ID) },
+	{ }						/* Terminating entry */
+};
+MODULE_DEVICE_TABLE(usb, id_table);
+
+static struct usb_serial_driver zyxel_omninet_device = {
+	.driver = {
+		.name =		"omninet",
+	},
+	.description =		"ZyXEL - omni.net usb",
+	.id_table =		id_table,
+	.num_bulk_out =		2,
+	.bulk_out_size =	OMNINET_BULKOUTSIZE,
+	.calc_num_ports =	omninet_calc_num_ports,
+	.port_probe =		omninet_port_probe,
+	.port_remove =		omninet_port_remove,
+	.process_read_urb =	omninet_process_read_urb,
+	.prepare_write_buffer =	omninet_prepare_write_buffer,
+};
+
+static struct usb_serial_driver * const serial_drivers[] = {
+	&zyxel_omninet_device, NULL
+};
+
+
+/*
+ * The protocol.
+ *
+ * The omni.net always exchange 64 bytes of data with the host. The first
+ * four bytes are the control header.
+ *
+ * oh_seq is a sequence number. Don't know if/how it's used.
+ * oh_len is the length of the data bytes in the packet.
+ * oh_xxx Bit-mapped, related to handshaking and status info.
+ *	I normally set it to 0x03 in transmitted frames.
+ *	7: Active when the TA is in a CONNECTed state.
+ *	6: unknown
+ *	5: handshaking, unknown
+ *	4: handshaking, unknown
+ *	3: unknown, usually 0
+ *	2: unknown, usually 0
+ *	1: handshaking, unknown, usually set to 1 in transmitted frames
+ *	0: handshaking, unknown, usually set to 1 in transmitted frames
+ * oh_pad Probably a pad byte.
+ *
+ * After the header you will find data bytes if oh_len was greater than zero.
+ */
+struct omninet_header {
+	__u8	oh_seq;
+	__u8	oh_len;
+	__u8	oh_xxx;
+	__u8	oh_pad;
+};
+
+struct omninet_data {
+	__u8	od_outseq;	/* Sequence number for bulk_out URBs */
+};
+
+static int omninet_calc_num_ports(struct usb_serial *serial,
+					struct usb_serial_endpoints *epds)
+{
+	/* We need only the second bulk-out for our single-port device. */
+	epds->bulk_out[0] = epds->bulk_out[1];
+	epds->num_bulk_out = 1;
+
+	return 1;
+}
+
+static int omninet_port_probe(struct usb_serial_port *port)
+{
+	struct omninet_data *od;
+
+	od = kzalloc_obj(*od);
+	if (!od)
+		return -ENOMEM;
+
+	usb_set_serial_port_data(port, od);
+
+	return 0;
+}
+
+static void omninet_port_remove(struct usb_serial_port *port)
+{
+	struct omninet_data *od;
+
+	od = usb_get_serial_port_data(port);
+	kfree(od);
+}
+
+static void omninet_process_read_urb(struct urb *urb)
+{
+	struct usb_serial_port *port = urb->context;
+	const struct omninet_header *hdr = urb->transfer_buffer;
+	const unsigned char *data;
+	size_t data_len;
+
+	if (urb->actual_length <= OMNINET_HEADERLEN || !hdr->oh_len)
+		return;
+
+	data = (char *)urb->transfer_buffer + OMNINET_HEADERLEN;
+	data_len = min_t(size_t, urb->actual_length - OMNINET_HEADERLEN,
+								hdr->oh_len);
+	tty_insert_flip_string(&port->port, data, data_len);
+	tty_flip_buffer_push(&port->port);
+}
+
+static int omninet_prepare_write_buffer(struct usb_serial_port *port,
+					void *buf, size_t count)
+{
+	struct omninet_data *od = usb_get_serial_port_data(port);
+	struct omninet_header *header = buf;
+
+	count = min_t(size_t, count, OMNINET_PAYLOADSIZE);
+
+	count = kfifo_out_locked(&port->write_fifo, buf + OMNINET_HEADERLEN,
+			count, &port->lock);
+
+	header->oh_seq = od->od_outseq++;
+	header->oh_len = count;
+	header->oh_xxx = 0x03;
+	header->oh_pad = 0x00;
+
+	/* always 64 bytes */
+	return OMNINET_BULKOUTSIZE;
+}
+
+module_usb_serial_driver(serial_drivers, id_table);
+
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL v2");