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, 132 insertions, 0 deletions

diff --git a/drivers/net/arcnet/com20020.h b/drivers/net/arcnet/com20020.h
new file mode 100644
index 000000000..68f49fdc2
--- /dev/null
+++ b/drivers/net/arcnet/com20020.h
@@ -0,0 +1,132 @@
+/*
+ * Linux ARCnet driver - COM20020 chipset support - function declarations
+ *
+ * Written 1997 by David Woodhouse.
+ * Written 1994-1999 by Avery Pennarun.
+ * Derived from skeleton.c by Donald Becker.
+ *
+ * Special thanks to Contemporary Controls, Inc. (www.ccontrols.com)
+ *  for sponsoring the further development of this driver.
+ *
+ * **********************
+ *
+ * The original copyright of skeleton.c was as follows:
+ *
+ * skeleton.c Written 1993 by Donald Becker.
+ * Copyright 1993 United States Government as represented by the
+ * Director, National Security Agency.  This software may only be used
+ * and distributed according to the terms of the GNU General Public License as
+ * modified by SRC, incorporated herein by reference.
+ *
+ * **********************
+ *
+ * For more details, see drivers/net/arcnet.c
+ *
+ * **********************
+ */
+#ifndef __COM20020_H
+#define __COM20020_H
+#include <linux/leds.h>
+
+int com20020_check(struct net_device *dev);
+int com20020_found(struct net_device *dev, int shared);
+extern const struct net_device_ops com20020_netdev_ops;
+
+/* The number of low I/O ports used by the card. */
+#define ARCNET_TOTAL_SIZE 8
+
+#define PLX_PCI_MAX_CARDS 2
+
+struct ledoffsets {
+	int green;
+	int red;
+};
+
+struct com20020_pci_channel_map {
+	u32 bar;
+	u32 offset;
+	u32 size;               /* 0x00 - auto, e.g. length of entire bar */
+};
+
+struct com20020_pci_card_info {
+	const char *name;
+	u8 devcount;
+
+	struct com20020_pci_channel_map chan_map_tbl[PLX_PCI_MAX_CARDS];
+	struct com20020_pci_channel_map misc_map;
+
+	struct ledoffsets leds[PLX_PCI_MAX_CARDS];
+	int rotary;
+
+	unsigned int flags;
+};
+
+struct com20020_priv {
+	struct com20020_pci_card_info *ci;
+	struct list_head list_dev;
+	resource_size_t misc;
+};
+
+struct com20020_dev {
+	struct list_head list;
+	struct net_device *dev;
+
+	struct led_classdev tx_led;
+	struct led_classdev recon_led;
+
+	struct com20020_priv *pci_priv;
+	int index;
+};
+
+#define COM20020_REG_W_INTMASK	0	/* writable */
+#define COM20020_REG_R_STATUS	0	/* readable */
+#define COM20020_REG_W_COMMAND	1	/* standard arcnet commands */
+#define COM20020_REG_R_DIAGSTAT	1	/* diagnostic status */
+#define COM20020_REG_W_ADDR_HI	2	/* control for IO-mapped memory */
+#define COM20020_REG_W_ADDR_LO	3
+#define COM20020_REG_RW_MEMDATA	4	/* data port for IO-mapped memory */
+#define COM20020_REG_W_SUBADR	5	/* the extended port _XREG refers to */
+#define COM20020_REG_W_CONFIG	6	/* configuration */
+#define COM20020_REG_W_XREG	7	/* extra
+					 * (indexed by _CONFIG or _SUBADDR)
+					 */
+
+/* in the ADDR_HI register */
+#define RDDATAflag	0x80	/* next access is a read (not a write) */
+
+/* in the DIAGSTAT register */
+#define NEWNXTIDflag	0x02	/* ID to which token is passed has changed */
+
+/* in the CONFIG register */
+#define RESETcfg	0x80	/* put card in reset state */
+#define TXENcfg		0x20	/* enable TX */
+#define XTOcfg(x)	((x) << 3)	/* extended timeout */
+
+/* in SETUP register */
+#define PROMISCset	0x10	/* enable RCV_ALL */
+#define P1MODE		0x80    /* enable P1-MODE for Backplane */
+#define SLOWARB		0x01    /* enable Slow Arbitration for >=5Mbps */
+
+/* COM2002x */
+#define SUB_TENTATIVE	0	/* tentative node ID */
+#define SUB_NODE	1	/* node ID */
+#define SUB_SETUP1	2	/* various options */
+#define SUB_TEST	3	/* test/diag register */
+
+/* COM20022 only */
+#define SUB_SETUP2	4	/* sundry options */
+#define SUB_BUSCTL	5	/* bus control options */
+#define SUB_DMACOUNT	6	/* DMA count options */
+
+static inline void com20020_set_subaddress(struct arcnet_local *lp,
+					   int ioaddr, int val)
+{
+	if (val < 4) {
+		lp->config = (lp->config & ~0x03) | val;
+		outb(lp->config, ioaddr + COM20020_REG_W_CONFIG);
+	} else {
+		outb(val, ioaddr + COM20020_REG_W_SUBADR);
+	}
+}
+
+#endif /* __COM20020_H */