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/media/dvb-frontends/mt352.h | 59 +++++++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+) create mode 100644 drivers/media/dvb-frontends/mt352.h (limited to 'drivers/media/dvb-frontends/mt352.h') diff --git a/drivers/media/dvb-frontends/mt352.h b/drivers/media/dvb-frontends/mt352.h new file mode 100644 index 000000000..acb1c3374 --- /dev/null +++ b/drivers/media/dvb-frontends/mt352.h @@ -0,0 +1,59 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Driver for Zarlink DVB-T MT352 demodulator + * + * Written by Holger Waechtler + * and Daniel Mack + * + * AVerMedia AVerTV DVB-T 771 support by + * Wolfram Joost + * + * Support for Samsung TDTC9251DH01C(M) tuner + * Copyright (C) 2004 Antonio Mancuso + * Amauri Celani + * + * DVICO FusionHDTV DVB-T1 and DVICO FusionHDTV DVB-T Lite support by + * Christopher Pascoe + */ + +#ifndef MT352_H +#define MT352_H + +#include + +struct mt352_config +{ + /* the demodulator's i2c address */ + u8 demod_address; + + /* frequencies in kHz */ + int adc_clock; // default: 20480 + int if2; // default: 36166 + + /* set if no pll is connected to the secondary i2c bus */ + int no_tuner; + + /* Initialise the demodulator and PLL. Cannot be NULL */ + int (*demod_init)(struct dvb_frontend* fe); +}; + +#if IS_REACHABLE(CONFIG_DVB_MT352) +extern struct dvb_frontend* mt352_attach(const struct mt352_config* config, + struct i2c_adapter* i2c); +#else +static inline struct dvb_frontend* mt352_attach(const struct mt352_config* config, + struct i2c_adapter* i2c) +{ + printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __func__); + return NULL; +} +#endif // CONFIG_DVB_MT352 + +static inline int mt352_write(struct dvb_frontend *fe, const u8 buf[], int len) { + int r = 0; + if (fe->ops.write) + r = fe->ops.write(fe, buf, len); + return r; +} + +#endif // MT352_H -- cgit v1.3.1