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, 148 insertions, 0 deletions

diff --git a/drivers/acpi/x86/apple.c b/drivers/acpi/x86/apple.c
new file mode 100644
index 000000000..45d0f16f3
--- /dev/null
+++ b/drivers/acpi/x86/apple.c
@@ -0,0 +1,148 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * apple.c - Apple ACPI quirks
+ * Copyright (C) 2017 Lukas Wunner <lukas@wunner.de>
+ */
+
+#include <linux/acpi.h>
+#include <linux/bitmap.h>
+#include <linux/platform_data/x86/apple.h>
+#include <linux/uuid.h>
+#include "../internal.h"
+
+/* Apple _DSM device properties GUID */
+static const guid_t apple_prp_guid =
+	GUID_INIT(0xa0b5b7c6, 0x1318, 0x441c,
+		  0xb0, 0xc9, 0xfe, 0x69, 0x5e, 0xaf, 0x94, 0x9b);
+
+/**
+ * acpi_extract_apple_properties - retrieve and convert Apple _DSM properties
+ * @adev: ACPI device for which to retrieve the properties
+ *
+ * Invoke Apple's custom _DSM once to check the protocol version and once more
+ * to retrieve the properties.  They are marshalled up in a single package as
+ * alternating key/value elements, unlike _DSD which stores them as a package
+ * of 2-element packages.  Convert to _DSD format and make them available under
+ * the primary fwnode.
+ */
+void acpi_extract_apple_properties(struct acpi_device *adev)
+{
+	unsigned int i, j = 0, newsize = 0, numprops, numvalid;
+	union acpi_object *props, *newprops;
+	unsigned long *valid = NULL;
+	void *free_space;
+
+	if (!x86_apple_machine)
+		return;
+
+	props = acpi_evaluate_dsm_typed(adev->handle, &apple_prp_guid, 1, 0,
+					NULL, ACPI_TYPE_BUFFER);
+	if (!props)
+		return;
+
+	if (!props->buffer.length)
+		goto out_free;
+
+	if (props->buffer.pointer[0] != 3) {
+		acpi_handle_info(adev->handle, FW_INFO
+				 "unsupported properties version %*ph\n",
+				 props->buffer.length, props->buffer.pointer);
+		goto out_free;
+	}
+
+	ACPI_FREE(props);
+	props = acpi_evaluate_dsm_typed(adev->handle, &apple_prp_guid, 1, 1,
+					NULL, ACPI_TYPE_PACKAGE);
+	if (!props)
+		return;
+
+	numprops = props->package.count / 2;
+	if (!numprops)
+		goto out_free;
+
+	valid = bitmap_zalloc(numprops, GFP_KERNEL);
+	if (!valid)
+		goto out_free;
+
+	/* newsize = key length + value length of each tuple */
+	for (i = 0; i < numprops; i++) {
+		union acpi_object *key = &props->package.elements[i * 2];
+		union acpi_object *val = &props->package.elements[i * 2 + 1];
+
+		if ( key->type != ACPI_TYPE_STRING ||
+		    (val->type != ACPI_TYPE_INTEGER &&
+		     val->type != ACPI_TYPE_BUFFER &&
+		     val->type != ACPI_TYPE_STRING))
+			continue; /* skip invalid properties */
+
+		__set_bit(i, valid);
+		newsize += key->string.length + 1;
+		if ( val->type == ACPI_TYPE_BUFFER)
+			newsize += val->buffer.length;
+		else if (val->type == ACPI_TYPE_STRING)
+			newsize += val->string.length + 1;
+	}
+
+	numvalid = bitmap_weight(valid, numprops);
+	if (numprops > numvalid)
+		acpi_handle_info(adev->handle, FW_INFO
+				 "skipped %u properties: wrong type\n",
+				 numprops - numvalid);
+	if (numvalid == 0)
+		goto out_free;
+
+	/* newsize += top-level package + 3 objects for each key/value tuple */
+	newsize	+= (1 + 3 * numvalid) * sizeof(union acpi_object);
+	newprops = ACPI_ALLOCATE_ZEROED(newsize);
+	if (!newprops)
+		goto out_free;
+
+	/* layout: top-level package | packages | key/value tuples | strings */
+	newprops->type = ACPI_TYPE_PACKAGE;
+	newprops->package.count = numvalid;
+	newprops->package.elements = &newprops[1];
+	free_space = &newprops[1 + 3 * numvalid];
+
+	for_each_set_bit(i, valid, numprops) {
+		union acpi_object *key = &props->package.elements[i * 2];
+		union acpi_object *val = &props->package.elements[i * 2 + 1];
+		unsigned int k = 1 + numvalid + j * 2; /* index into newprops */
+		unsigned int v = k + 1;
+
+		newprops[1 + j].type = ACPI_TYPE_PACKAGE;
+		newprops[1 + j].package.count = 2;
+		newprops[1 + j].package.elements = &newprops[k];
+
+		newprops[k].type = ACPI_TYPE_STRING;
+		newprops[k].string.length = key->string.length;
+		newprops[k].string.pointer = free_space;
+		memcpy(free_space, key->string.pointer, key->string.length);
+		free_space += key->string.length + 1;
+
+		newprops[v].type = val->type;
+		if (val->type == ACPI_TYPE_INTEGER) {
+			newprops[v].integer.value = val->integer.value;
+		} else if (val->type == ACPI_TYPE_STRING) {
+			newprops[v].string.length = val->string.length;
+			newprops[v].string.pointer = free_space;
+			memcpy(free_space, val->string.pointer,
+			       val->string.length);
+			free_space += val->string.length + 1;
+		} else {
+			newprops[v].buffer.length = val->buffer.length;
+			newprops[v].buffer.pointer = free_space;
+			memcpy(free_space, val->buffer.pointer,
+			       val->buffer.length);
+			free_space += val->buffer.length;
+		}
+		j++; /* count valid properties */
+	}
+	WARN_ON(free_space != (void *)newprops + newsize);
+
+	adev->data.pointer = newprops;
+	acpi_data_add_props(&adev->data, &apple_prp_guid, newprops);
+
+out_free:
+	ACPI_FREE(props);
+	bitmap_free(valid);
+}