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/misc/pvpanic/pvpanic-pci.c | 49 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) create mode 100644 drivers/misc/pvpanic/pvpanic-pci.c (limited to 'drivers/misc/pvpanic/pvpanic-pci.c') diff --git a/drivers/misc/pvpanic/pvpanic-pci.c b/drivers/misc/pvpanic/pvpanic-pci.c new file mode 100644 index 000000000..572c6148a --- /dev/null +++ b/drivers/misc/pvpanic/pvpanic-pci.c @@ -0,0 +1,49 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Pvpanic PCI Device Support + * + * Copyright (C) 2021 Oracle. + */ + +#include +#include +#include +#include + +#include "pvpanic.h" + +#define PCI_DEVICE_ID_REDHAT_PVPANIC 0x0011 + +MODULE_AUTHOR("Mihai Carabas "); +MODULE_DESCRIPTION("pvpanic device driver"); +MODULE_LICENSE("GPL"); + +static int pvpanic_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent) +{ + void __iomem *base; + int ret; + + ret = pcim_enable_device(pdev); + if (ret < 0) + return ret; + + base = pcim_iomap(pdev, 0, 0); + if (!base) + return -ENOMEM; + + return devm_pvpanic_probe(&pdev->dev, base); +} + +static const struct pci_device_id pvpanic_pci_id_tbl[] = { + { PCI_DEVICE(PCI_VENDOR_ID_REDHAT, PCI_DEVICE_ID_REDHAT_PVPANIC) }, + { } +}; +MODULE_DEVICE_TABLE(pci, pvpanic_pci_id_tbl); + +static struct pci_driver pvpanic_pci_driver = { + .name = "pvpanic-pci", + .id_table = pvpanic_pci_id_tbl, + .probe = pvpanic_pci_probe, + .dev_groups = pvpanic_dev_groups, +}; +module_pci_driver(pvpanic_pci_driver); -- cgit v1.3.1