From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- drivers/input/joystick/joydump.c | 142 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 142 insertions(+) create mode 100644 drivers/input/joystick/joydump.c (limited to 'drivers/input/joystick/joydump.c') diff --git a/drivers/input/joystick/joydump.c b/drivers/input/joystick/joydump.c new file mode 100644 index 000000000..c9cbdcc7f --- /dev/null +++ b/drivers/input/joystick/joydump.c @@ -0,0 +1,142 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (c) 1996-2001 Vojtech Pavlik + */ + +/* + * This is just a very simple driver that can dump the data + * out of the joystick port into the syslog ... + */ + +#include +#include +#include +#include +#include + +#define DRIVER_DESC "Gameport data dumper module" + +MODULE_AUTHOR("Vojtech Pavlik "); +MODULE_DESCRIPTION(DRIVER_DESC); +MODULE_LICENSE("GPL"); + +#define BUF_SIZE 256 + +struct joydump { + unsigned int time; + unsigned char data; +}; + +static int joydump_connect(struct gameport *gameport, struct gameport_driver *drv) +{ + struct joydump *buf; /* all entries */ + struct joydump *dump, *prev; /* one entry each */ + int axes[4], buttons; + int i, j, t, timeout; + unsigned long flags; + unsigned char u; + + printk(KERN_INFO "joydump: ,------------------ START ----------------.\n"); + printk(KERN_INFO "joydump: | Dumping: %30s |\n", gameport->phys); + printk(KERN_INFO "joydump: | Speed: %28d kHz |\n", gameport->speed); + + if (gameport_open(gameport, drv, GAMEPORT_MODE_RAW)) { + + printk(KERN_INFO "joydump: | Raw mode not available - trying cooked. |\n"); + + if (gameport_open(gameport, drv, GAMEPORT_MODE_COOKED)) { + + printk(KERN_INFO "joydump: | Cooked not available either. Failing. |\n"); + printk(KERN_INFO "joydump: `------------------- END -----------------'\n"); + return -ENODEV; + } + + gameport_cooked_read(gameport, axes, &buttons); + + for (i = 0; i < 4; i++) + printk(KERN_INFO "joydump: | Axis %d: %4d. |\n", i, axes[i]); + printk(KERN_INFO "joydump: | Buttons %02x. |\n", buttons); + printk(KERN_INFO "joydump: `------------------- END -----------------'\n"); + } + + timeout = gameport_time(gameport, 10000); /* 10 ms */ + + buf = kmalloc_objs(struct joydump, BUF_SIZE); + if (!buf) { + printk(KERN_INFO "joydump: no memory for testing\n"); + goto jd_end; + } + dump = buf; + t = 0; + i = 1; + + local_irq_save(flags); + + u = gameport_read(gameport); + + dump->data = u; + dump->time = t; + dump++; + + gameport_trigger(gameport); + + while (i < BUF_SIZE && t < timeout) { + + dump->data = gameport_read(gameport); + + if (dump->data ^ u) { + u = dump->data; + dump->time = t; + i++; + dump++; + } + t++; + } + + local_irq_restore(flags); + +/* + * Dump data. + */ + + t = i; + dump = buf; + prev = dump; + + printk(KERN_INFO "joydump: >------------------ DATA -----------------<\n"); + printk(KERN_INFO "joydump: | index: %3d delta: %3d us data: ", 0, 0); + for (j = 7; j >= 0; j--) + printk("%d", (dump->data >> j) & 1); + printk(" |\n"); + dump++; + + for (i = 1; i < t; i++, dump++, prev++) { + printk(KERN_INFO "joydump: | index: %3d delta: %3d us data: ", + i, dump->time - prev->time); + for (j = 7; j >= 0; j--) + printk("%d", (dump->data >> j) & 1); + printk(" |\n"); + } + kfree(buf); + +jd_end: + printk(KERN_INFO "joydump: `------------------- END -----------------'\n"); + + return 0; +} + +static void joydump_disconnect(struct gameport *gameport) +{ + gameport_close(gameport); +} + +static struct gameport_driver joydump_drv = { + .driver = { + .name = "joydump", + }, + .description = DRIVER_DESC, + .connect = joydump_connect, + .disconnect = joydump_disconnect, +}; + +module_gameport_driver(joydump_drv); -- cgit v1.3.1