summaryrefslogtreecommitdiffstats
path: root/drivers/tty/ttynull.c
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2026-10-02 12:17:24 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-10-02 12:17:24 -0700
commit3f1fe48a36b0b6722dc3fd421d93512bac138e9a (patch)
treeb767d7f6e26bc64334d3f14f8422d187239dc45d /drivers/tty/ttynull.c
downloadlinux-stable-3f1fe48a36b0b6722dc3fd421d93512bac138e9a.tar.gz
linux-stable-3f1fe48a36b0b6722dc3fd421d93512bac138e9a.zip
Merge tag 'io_uring-7.3-20261002' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linuxgrafted
Pull io_uring fixes from Jens Axboe: - Fix a task_work add use-after-free with SQPOLL. The sqpoll thread could pop and complete the last request while io_req_normal_work_add() was still looking at them after the mpscq push. Use the same approach as DEFER_TASKRUN to protect from that, holding an RCU read lock across the add, and have exit wait for an RCU grace period for SQPOLL rings as well. - CQE32 ring fixes: correct the free entry check for 32b CQEs, zero the big_cqe for aux CQEs, and only post the dummy skip CQE on CQE_MIXED rings - Mark the source filter table as COW when cloning bpf filters, so registering another filter on the source doesn't modify the shared table in place - Initialize the task context before running the BPF loop - Requeue zcrx multishot receives stopped by a local resource - End a TX_TIMESTAMP multishot cmd when the CQ is full (lollipopkit) * tag 'io_uring-7.3-20261002' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux: io_uring: fix task_work add use-after-free with SQPOLL io_uring/cmd_net: end TX_TIMESTAMP multishot when the CQ is full io_uring/zcrx: requeue multishot receives stopped by a local resource io_uring: initialize task context before running the BPF loop io_uring: zero big_cqe for aux CQEs on CQE32 rings io_uring: fix free entry check for 32b CQEs on CQE32 rings io_uring: only post the dummy skip CQE on CQE_MIXED rings io_uring/bpf_filter: mark source as COW when cloning filters
Diffstat (limited to 'drivers/tty/ttynull.c')
-rw-r--r--drivers/tty/ttynull.c110
1 files changed, 110 insertions, 0 deletions
diff --git a/drivers/tty/ttynull.c b/drivers/tty/ttynull.c
new file mode 100644
index 000000000..6b2f7208b
--- /dev/null
+++ b/drivers/tty/ttynull.c
@@ -0,0 +1,110 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Axis Communications AB
+ *
+ * Based on ttyprintk.c:
+ * Copyright (C) 2010 Samo Pogacnik
+ */
+
+#include <linux/console.h>
+#include <linux/module.h>
+#include <linux/tty.h>
+
+static const struct tty_port_operations ttynull_port_ops;
+static struct tty_driver *ttynull_driver;
+static struct tty_port ttynull_port;
+
+static int ttynull_open(struct tty_struct *tty, struct file *filp)
+{
+ return tty_port_open(&ttynull_port, tty, filp);
+}
+
+static void ttynull_close(struct tty_struct *tty, struct file *filp)
+{
+ tty_port_close(&ttynull_port, tty, filp);
+}
+
+static void ttynull_hangup(struct tty_struct *tty)
+{
+ tty_port_hangup(&ttynull_port);
+}
+
+static ssize_t ttynull_write(struct tty_struct *tty, const u8 *buf,
+ size_t count)
+{
+ return count;
+}
+
+static unsigned int ttynull_write_room(struct tty_struct *tty)
+{
+ return 65536;
+}
+
+static const struct tty_operations ttynull_ops = {
+ .open = ttynull_open,
+ .close = ttynull_close,
+ .hangup = ttynull_hangup,
+ .write = ttynull_write,
+ .write_room = ttynull_write_room,
+};
+
+static struct tty_driver *ttynull_device(struct console *c, int *index)
+{
+ *index = 0;
+ return ttynull_driver;
+}
+
+static struct console ttynull_console = {
+ .name = "ttynull",
+ .device = ttynull_device,
+};
+
+static int __init ttynull_init(void)
+{
+ struct tty_driver *driver;
+ int ret;
+
+ driver = tty_alloc_driver(1,
+ TTY_DRIVER_RESET_TERMIOS |
+ TTY_DRIVER_REAL_RAW |
+ TTY_DRIVER_UNNUMBERED_NODE);
+ if (IS_ERR(driver))
+ return PTR_ERR(driver);
+
+ tty_port_init(&ttynull_port);
+ ttynull_port.ops = &ttynull_port_ops;
+
+ driver->driver_name = "ttynull";
+ driver->name = "ttynull";
+ driver->type = TTY_DRIVER_TYPE_CONSOLE;
+ driver->init_termios = tty_std_termios;
+ driver->init_termios.c_oflag = OPOST | OCRNL | ONOCR | ONLRET;
+ tty_set_operations(driver, &ttynull_ops);
+ tty_port_link_device(&ttynull_port, driver, 0);
+
+ ret = tty_register_driver(driver);
+ if (ret < 0) {
+ tty_driver_kref_put(driver);
+ tty_port_destroy(&ttynull_port);
+ return ret;
+ }
+
+ ttynull_driver = driver;
+ register_console(&ttynull_console);
+
+ return 0;
+}
+
+static void __exit ttynull_exit(void)
+{
+ unregister_console(&ttynull_console);
+ tty_unregister_driver(ttynull_driver);
+ tty_driver_kref_put(ttynull_driver);
+ tty_port_destroy(&ttynull_port);
+}
+
+module_init(ttynull_init);
+module_exit(ttynull_exit);
+
+MODULE_DESCRIPTION("NULL TTY driver");
+MODULE_LICENSE("GPL v2");