ftrace: Synchronize the initialization of ftrace_opsgrafted

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 <rostedt@goodmis.org>

1 files changed, 125 insertions, 0 deletions

diff --git a/drivers/ata/pata_piccolo.c b/drivers/ata/pata_piccolo.c
new file mode 100644
index 000000000..beb53bd99
--- /dev/null
+++ b/drivers/ata/pata_piccolo.c
@@ -0,0 +1,125 @@
+/*
+ *  pata_piccolo.c - Toshiba Piccolo PATA/SATA controller driver.
+ *
+ *  This is basically an update to ata_generic.c to add Toshiba Piccolo support
+ *  then split out to keep ata_generic "clean".
+ *
+ *  Copyright 2005 Red Hat Inc, all rights reserved.
+ *
+ *  Elements from ide/pci/generic.c
+ *	    Copyright (C) 2001-2002	Andre Hedrick <andre@linux-ide.org>
+ *	    Portions (C) Copyright 2002  Red Hat Inc <alan@redhat.com>
+ *
+ *  May be copied or modified under the terms of the GNU General Public License
+ *
+ *  The timing data tables/programming info are courtesy of the NetBSD driver
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/blkdev.h>
+#include <linux/delay.h>
+#include <scsi/scsi_host.h>
+#include <linux/libata.h>
+
+#define DRV_NAME "pata_piccolo"
+#define DRV_VERSION "0.0.1"
+
+
+
+static void tosh_set_piomode(struct ata_port *ap, struct ata_device *adev)
+{
+	static const u16 pio[6] = {	/* For reg 0x50 low word & E088 */
+		0x0566, 0x0433, 0x0311, 0x0201, 0x0200, 0x0100
+	};
+	struct pci_dev *pdev = to_pci_dev(ap->host->dev);
+	u16 conf;
+	pci_read_config_word(pdev, 0x50, &conf);
+	conf &= 0xE088;
+	conf |= pio[adev->pio_mode - XFER_PIO_0];
+	pci_write_config_word(pdev, 0x50, conf);
+}
+
+static void tosh_set_dmamode(struct ata_port *ap, struct ata_device *adev)
+{
+	struct pci_dev *pdev = to_pci_dev(ap->host->dev);
+	u32 conf;
+	pci_read_config_dword(pdev, 0x5C, &conf);
+	conf &= 0x78FFE088;	/* Keep the other bits */
+	if (adev->dma_mode >= XFER_UDMA_0) {
+		int udma = adev->dma_mode - XFER_UDMA_0;
+		conf |= 0x80000000;
+		conf |= (udma + 2) << 28;
+		conf |= (2 - udma) * 0x111;	/* spread into three nibbles */
+	} else {
+		static const u32 mwdma[4] = {
+			0x0655, 0x0200, 0x0200, 0x0100
+		};
+		conf |= mwdma[adev->dma_mode - XFER_MW_DMA_0];
+	}
+	pci_write_config_dword(pdev, 0x5C, conf);
+}
+
+
+static const struct scsi_host_template tosh_sht = {
+	ATA_BMDMA_SHT(DRV_NAME),
+};
+
+static struct ata_port_operations tosh_port_ops = {
+	.inherits	= &ata_bmdma_port_ops,
+	.cable_detect	= ata_cable_unknown,
+	.set_piomode	= tosh_set_piomode,
+	.set_dmamode	= tosh_set_dmamode
+};
+
+/**
+ *	ata_tosh_init_one		-	attach generic IDE
+ *	@dev: PCI device found
+ *	@id: match entry
+ *
+ *	Called each time a matching IDE interface is found. We check if the
+ *	interface is one we wish to claim and if so we perform any chip
+ *	specific hacks then let the ATA layer do the heavy lifting.
+ */
+
+static int ata_tosh_init_one(struct pci_dev *dev, const struct pci_device_id *id)
+{
+	static const struct ata_port_info info = {
+		.flags = ATA_FLAG_SLAVE_POSS,
+		.pio_mask = ATA_PIO5,
+		.mwdma_mask = ATA_MWDMA2,
+		.udma_mask = ATA_UDMA2,
+		.port_ops = &tosh_port_ops
+	};
+	const struct ata_port_info *ppi[] = { &info, &ata_dummy_port_info };
+	/* Just one port for the moment */
+	return ata_pci_bmdma_init_one(dev, ppi, &tosh_sht, NULL, 0);
+}
+
+static const struct pci_device_id ata_tosh[] = {
+	{ PCI_DEVICE(PCI_VENDOR_ID_TOSHIBA,PCI_DEVICE_ID_TOSHIBA_PICCOLO_1), },
+	{ PCI_DEVICE(PCI_VENDOR_ID_TOSHIBA,PCI_DEVICE_ID_TOSHIBA_PICCOLO_2),  },
+	{ PCI_DEVICE(PCI_VENDOR_ID_TOSHIBA,PCI_DEVICE_ID_TOSHIBA_PICCOLO_3),  },
+	{ PCI_DEVICE(PCI_VENDOR_ID_TOSHIBA,PCI_DEVICE_ID_TOSHIBA_PICCOLO_5),  },
+	{ 0, },
+};
+
+static struct pci_driver ata_tosh_pci_driver = {
+	.name 		= DRV_NAME,
+	.id_table	= ata_tosh,
+	.probe 		= ata_tosh_init_one,
+	.remove		= ata_pci_remove_one,
+#ifdef CONFIG_PM_SLEEP
+	.suspend	= ata_pci_device_suspend,
+	.resume		= ata_pci_device_resume,
+#endif
+};
+
+module_pci_driver(ata_tosh_pci_driver);
+
+MODULE_AUTHOR("Alan Cox");
+MODULE_DESCRIPTION("Low level driver for Toshiba Piccolo ATA");
+MODULE_LICENSE("GPL");
+MODULE_DEVICE_TABLE(pci, ata_tosh);
+MODULE_VERSION(DRV_VERSION);