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/pci/pwrctrl/generic.c | 139 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 139 insertions(+) create mode 100644 drivers/pci/pwrctrl/generic.c (limited to 'drivers/pci/pwrctrl/generic.c') diff --git a/drivers/pci/pwrctrl/generic.c b/drivers/pci/pwrctrl/generic.c new file mode 100644 index 000000000..d56171e0e --- /dev/null +++ b/drivers/pci/pwrctrl/generic.c @@ -0,0 +1,139 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2024 Linaro Ltd. + * Author: Manivannan Sadhasivam + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +struct slot_pwrctrl { + struct pci_pwrctrl pwrctrl; + struct regulator_bulk_data *supplies; + int num_supplies; + struct clk *clk; + struct pwrseq_desc *pwrseq; +}; + +static int slot_pwrctrl_power_on(struct pci_pwrctrl *pwrctrl) +{ + struct slot_pwrctrl *slot = container_of(pwrctrl, + struct slot_pwrctrl, pwrctrl); + int ret; + + if (slot->pwrseq) { + pwrseq_enable(slot->pwrseq); + return 0; + } + + ret = regulator_bulk_enable(slot->num_supplies, slot->supplies); + if (ret < 0) { + dev_err(slot->pwrctrl.dev, "Failed to enable slot regulators\n"); + return ret; + } + + return clk_prepare_enable(slot->clk); +} + +static int slot_pwrctrl_power_off(struct pci_pwrctrl *pwrctrl) +{ + struct slot_pwrctrl *slot = container_of(pwrctrl, + struct slot_pwrctrl, pwrctrl); + + if (slot->pwrseq) { + pwrseq_disable(slot->pwrseq); + return 0; + } + + regulator_bulk_disable(slot->num_supplies, slot->supplies); + clk_disable_unprepare(slot->clk); + + return 0; +} + +static void devm_slot_pwrctrl_release(void *data) +{ + struct slot_pwrctrl *slot = data; + + regulator_bulk_free(slot->num_supplies, slot->supplies); +} + +static int slot_pwrctrl_probe(struct platform_device *pdev) +{ + struct slot_pwrctrl *slot; + struct device *dev = &pdev->dev; + int ret; + + slot = devm_kzalloc(dev, sizeof(*slot), GFP_KERNEL); + if (!slot) + return -ENOMEM; + + if (of_graph_is_present(dev_of_node(dev))) { + slot->pwrseq = devm_pwrseq_get(dev, "pcie"); + if (IS_ERR(slot->pwrseq)) + return dev_err_probe(dev, PTR_ERR(slot->pwrseq), + "Failed to get the power sequencer\n"); + + goto skip_resources; + } + + ret = of_regulator_bulk_get_all(dev, dev_of_node(dev), + &slot->supplies); + if (ret < 0) + return dev_err_probe(dev, ret, "Failed to get slot regulators\n"); + + slot->num_supplies = ret; + + slot->clk = devm_clk_get_optional(dev, NULL); + if (IS_ERR(slot->clk)) + return dev_err_probe(dev, PTR_ERR(slot->clk), + "Failed to enable slot clock\n"); + +skip_resources: + slot->pwrctrl.power_on = slot_pwrctrl_power_on; + slot->pwrctrl.power_off = slot_pwrctrl_power_off; + + ret = devm_add_action_or_reset(dev, devm_slot_pwrctrl_release, slot); + if (ret) + return ret; + + pci_pwrctrl_init(&slot->pwrctrl, dev); + + ret = devm_pci_pwrctrl_device_set_ready(dev, &slot->pwrctrl); + if (ret) + return dev_err_probe(dev, ret, "Failed to register pwrctrl driver\n"); + + return 0; +} + +static const struct of_device_id slot_pwrctrl_of_match[] = { + { + .compatible = "pciclass,0604", + }, + /* Renesas UPD720201/UPD720202 USB 3.0 xHCI Host Controller */ + { + .compatible = "pci1912,0014", + }, + { } +}; +MODULE_DEVICE_TABLE(of, slot_pwrctrl_of_match); + +static struct platform_driver slot_pwrctrl_driver = { + .driver = { + .name = "pci-pwrctrl-slot", + .of_match_table = slot_pwrctrl_of_match, + }, + .probe = slot_pwrctrl_probe, +}; +module_platform_driver(slot_pwrctrl_driver); + +MODULE_AUTHOR("Manivannan Sadhasivam "); +MODULE_DESCRIPTION("Generic PCI Power Control driver for PCI Slots"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1