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, 476 insertions, 0 deletions

diff --git a/fs/btrfs/tests/chunk-allocation-tests.c b/fs/btrfs/tests/chunk-allocation-tests.c
new file mode 100644
index 000000000..9beb0602f
--- /dev/null
+++ b/fs/btrfs/tests/chunk-allocation-tests.c
@@ -0,0 +1,476 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2026 Meta.  All rights reserved.
+ */
+
+#include <linux/sizes.h>
+#include "btrfs-tests.h"
+#include "../volumes.h"
+#include "../disk-io.h"
+#include "../extent-io-tree.h"
+
+/*
+ * Tests for chunk allocator pending extent internals.
+ * These two functions form the core of searching the chunk allocation pending
+ * extent bitmap and have relatively easily definable semantics, so unit
+ * testing them can help ensure the correctness of chunk allocation.
+ */
+
+/*
+ * Describes the inputs to the system and expected results
+ * when testing btrfs_find_hole_in_pending_extents().
+ */
+struct pending_extent_test_case {
+	const char *name;
+	/* Input range to search. */
+	u64 hole_start;
+	u64 hole_len;
+	/* The size of hole we are searching for. */
+	u64 min_hole_size;
+	/*
+	 * Pending extents to set up (up to 2 for up to 3 holes)
+	 * If len == 0, then it is skipped.
+	 */
+	struct {
+		u64 start;
+		u64 len;
+	} pending_extents[2];
+	/* Expected outputs. */
+	bool expected_found;
+	u64 expected_start;
+	u64 expected_len;
+};
+
+static const struct pending_extent_test_case find_hole_tests[] = {
+	{
+		.name = "no pending extents",
+		.hole_start = 0,
+		.hole_len = 10ULL * SZ_1G,
+		.min_hole_size = SZ_1G,
+		.pending_extents = { },
+		.expected_found = true,
+		.expected_start = 0,
+		.expected_len = 10ULL * SZ_1G,
+	},
+	{
+		.name = "pending extent at start of range",
+		.hole_start = 0,
+		.hole_len = 10ULL * SZ_1G,
+		.min_hole_size = SZ_1G,
+		.pending_extents = {
+			{ .start = 0, .len = SZ_1G },
+		},
+		.expected_found = true,
+		.expected_start = SZ_1G,
+		.expected_len = 9ULL * SZ_1G,
+	},
+	{
+		.name = "pending extent overlapping start of range",
+		.hole_start = SZ_1G,
+		.hole_len = 9ULL * SZ_1G,
+		.min_hole_size = SZ_1G,
+		.pending_extents = {
+			{ .start = 0, .len = SZ_2G },
+		},
+		.expected_found = true,
+		.expected_start = SZ_2G,
+		.expected_len = 8ULL * SZ_1G,
+	},
+	{
+		.name = "two holes; first hole is exactly big enough",
+		.hole_start = 0,
+		.hole_len = 10ULL * SZ_1G,
+		.min_hole_size = SZ_1G,
+		.pending_extents = {
+			{ .start = SZ_1G, .len = SZ_1G },
+		},
+		.expected_found = true,
+		.expected_start = 0,
+		.expected_len = SZ_1G,
+	},
+	{
+		.name = "two holes; first hole is big enough",
+		.hole_start = 0,
+		.hole_len = 10ULL * SZ_1G,
+		.min_hole_size = SZ_1G,
+		.pending_extents = {
+			{ .start = SZ_2G, .len = SZ_1G },
+		},
+		.expected_found = true,
+		.expected_start = 0,
+		.expected_len = SZ_2G,
+	},
+	{
+		.name = "two holes; second hole is big enough",
+		.hole_start = 0,
+		.hole_len = 10ULL * SZ_1G,
+		.min_hole_size = SZ_2G,
+		.pending_extents = {
+			{ .start = SZ_1G, .len = SZ_1G },
+		},
+		.expected_found = true,
+		.expected_start = SZ_2G,
+		.expected_len = 8ULL * SZ_1G,
+	},
+	{
+		.name = "three holes; first hole big enough",
+		.hole_start = 0,
+		.hole_len = 10ULL * SZ_1G,
+		.min_hole_size = SZ_2G,
+		.pending_extents = {
+			{ .start = SZ_2G, .len = SZ_1G },
+			{ .start = 4ULL * SZ_1G, .len = SZ_1G },
+		},
+		.expected_found = true,
+		.expected_start = 0,
+		.expected_len = SZ_2G,
+	},
+	{
+		.name = "three holes; second hole big enough",
+		.hole_start = 0,
+		.hole_len = 10ULL * SZ_1G,
+		.min_hole_size = SZ_2G,
+		.pending_extents = {
+			{ .start = SZ_1G, .len = SZ_1G },
+			{ .start = 5ULL * SZ_1G, .len = SZ_1G },
+		},
+		.expected_found = true,
+		.expected_start = SZ_2G,
+		.expected_len = 3ULL * SZ_1G,
+	},
+	{
+		.name = "three holes; third hole big enough",
+		.hole_start = 0,
+		.hole_len = 10ULL * SZ_1G,
+		.min_hole_size = SZ_2G,
+		.pending_extents = {
+			{ .start = SZ_1G, .len = SZ_1G },
+			{ .start = 3ULL * SZ_1G, .len = 5ULL * SZ_1G },
+		},
+		.expected_found = true,
+		.expected_start = 8ULL * SZ_1G,
+		.expected_len = SZ_2G,
+	},
+	{
+		.name = "three holes; all holes too small",
+		.hole_start = 0,
+		.hole_len = 10ULL * SZ_1G,
+		.min_hole_size = SZ_2G,
+		.pending_extents = {
+			{ .start = SZ_1G, .len = SZ_1G },
+			{ .start = 3ULL * SZ_1G, .len = 6ULL * SZ_1G },
+		},
+		.expected_found = false,
+		.expected_start = 0,
+		.expected_len = SZ_1G,
+	},
+	{
+		.name = "three holes; all holes too small; first biggest",
+		.hole_start = 0,
+		.hole_len = 10ULL * SZ_1G,
+		.min_hole_size = 3ULL * SZ_1G,
+		.pending_extents = {
+			{ .start = SZ_2G, .len = SZ_1G },
+			{ .start = 4ULL * SZ_1G, .len = 5ULL * SZ_1G },
+		},
+		.expected_found = false,
+		.expected_start = 0,
+		.expected_len = SZ_2G,
+	},
+	{
+		.name = "three holes; all holes too small; second biggest",
+		.hole_start = 0,
+		.hole_len = 10ULL * SZ_1G,
+		.min_hole_size = 3ULL * SZ_1G,
+		.pending_extents = {
+			{ .start = SZ_1G, .len = SZ_1G },
+			{ .start = 4ULL * SZ_1G, .len = 5ULL * SZ_1G },
+		},
+		.expected_found = false,
+		.expected_start = SZ_2G,
+		.expected_len = SZ_2G,
+	},
+	{
+		.name = "three holes; all holes too small; third biggest",
+		.hole_start = 0,
+		.hole_len = 10ULL * SZ_1G,
+		.min_hole_size = 3ULL * SZ_1G,
+		.pending_extents = {
+			{ .start = SZ_1G, .len = SZ_1G },
+			{ .start = 3ULL * SZ_1G, .len = 5ULL * SZ_1G },
+		},
+		.expected_found = false,
+		.expected_start = 8ULL * SZ_1G,
+		.expected_len = SZ_2G,
+	},
+	{
+		.name = "hole entirely allocated by pending",
+		.hole_start = 0,
+		.hole_len = 10ULL * SZ_1G,
+		.min_hole_size = SZ_1G,
+		.pending_extents = {
+			{ .start = 0, .len = 10ULL * SZ_1G },
+		},
+		.expected_found = false,
+		.expected_start = 10ULL * SZ_1G,
+		.expected_len = 0,
+	},
+	{
+		.name = "pending extent at end of range",
+		.hole_start = 0,
+		.hole_len = 10ULL * SZ_1G,
+		.min_hole_size = SZ_1G,
+		.pending_extents = {
+			{ .start = 9ULL * SZ_1G, .len = SZ_2G },
+		},
+		.expected_found = true,
+		.expected_start = 0,
+		.expected_len = 9ULL * SZ_1G,
+	},
+	{
+		.name = "zero length input",
+		.hole_start = SZ_1G,
+		.hole_len = 0,
+		.min_hole_size = SZ_1G,
+		.pending_extents = { },
+		.expected_found = false,
+		.expected_start = SZ_1G,
+		.expected_len = 0,
+	},
+};
+
+static int test_find_hole_in_pending(u32 sectorsize, u32 nodesize)
+{
+	struct btrfs_fs_info *fs_info;
+	struct btrfs_device *device;
+	int ret = 0;
+
+	test_msg("running find_hole_in_pending_extents tests");
+
+	fs_info = btrfs_alloc_dummy_fs_info(nodesize, sectorsize);
+	if (!fs_info) {
+		test_std_err(TEST_ALLOC_FS_INFO);
+		return -ENOMEM;
+	}
+
+	device = btrfs_alloc_dummy_device(fs_info);
+	if (IS_ERR(device)) {
+		test_err("failed to allocate dummy device");
+		ret = PTR_ERR(device);
+		goto out_free_fs_info;
+	}
+	device->fs_info = fs_info;
+
+	for (int i = 0; i < ARRAY_SIZE(find_hole_tests); i++) {
+		const struct pending_extent_test_case *test_case = &find_hole_tests[i];
+		u64 hole_start = test_case->hole_start;
+		u64 hole_len = test_case->hole_len;
+		bool found;
+
+		for (int j = 0; j < ARRAY_SIZE(test_case->pending_extents); j++) {
+			u64 start = test_case->pending_extents[j].start;
+			u64 len = test_case->pending_extents[j].len;
+
+			if (!len)
+				continue;
+			btrfs_set_extent_bit(&device->alloc_state,
+					     start, start + len - 1,
+					     CHUNK_ALLOCATED, NULL);
+		}
+
+		mutex_lock(&fs_info->chunk_mutex);
+		found = btrfs_find_hole_in_pending_extents(device, &hole_start, &hole_len,
+							   test_case->min_hole_size);
+		mutex_unlock(&fs_info->chunk_mutex);
+
+		if (found != test_case->expected_found) {
+			test_err("%s: expected found=%d, got found=%d",
+				 test_case->name, test_case->expected_found, found);
+			ret = -EINVAL;
+			goto out_clear_pending_extents;
+		}
+		if (hole_start != test_case->expected_start ||
+		    hole_len != test_case->expected_len) {
+			test_err("%s: expected [%llu, %llu), got [%llu, %llu)",
+				 test_case->name, test_case->expected_start,
+				 test_case->expected_start +
+					 test_case->expected_len,
+				 hole_start, hole_start + hole_len);
+			ret = -EINVAL;
+			goto out_clear_pending_extents;
+		}
+out_clear_pending_extents:
+		btrfs_clear_extent_bit(&device->alloc_state, 0, (u64)-1,
+				       CHUNK_ALLOCATED, NULL);
+		if (ret)
+			break;
+	}
+
+out_free_fs_info:
+	btrfs_free_dummy_fs_info(fs_info);
+	return ret;
+}
+
+/*
+ * Describes the inputs to the system and expected results
+ * when testing btrfs_first_pending_extent().
+ */
+struct first_pending_test_case {
+	const char *name;
+	/* The range to look for a pending extent in. */
+	u64 hole_start;
+	u64 hole_len;
+	/* The pending extent to look for. */
+	struct {
+		u64 start;
+		u64 len;
+	} pending_extent;
+	/* Expected outputs. */
+	bool expected_found;
+	u64 expected_pending_start;
+	u64 expected_pending_end;
+};
+
+static const struct first_pending_test_case first_pending_tests[] = {
+	{
+		.name = "no pending extent",
+		.hole_start = 0,
+		.hole_len = 10ULL * SZ_1G,
+		.pending_extent = { 0, 0 },
+		.expected_found = false,
+	},
+	{
+		.name = "pending extent at search start",
+		.hole_start = SZ_1G,
+		.hole_len = 9ULL * SZ_1G,
+		.pending_extent = { SZ_1G, SZ_1G },
+		.expected_found = true,
+		.expected_pending_start = SZ_1G,
+		.expected_pending_end = SZ_2G - 1,
+	},
+	{
+		.name = "pending extent overlapping search start",
+		.hole_start = SZ_1G,
+		.hole_len = 9ULL * SZ_1G,
+		.pending_extent = { 0, SZ_2G },
+		.expected_found = true,
+		.expected_pending_start = 0,
+		.expected_pending_end = SZ_2G - 1,
+	},
+	{
+		.name = "pending extent inside search range",
+		.hole_start = 0,
+		.hole_len = 10ULL * SZ_1G,
+		.pending_extent = { SZ_2G, SZ_1G },
+		.expected_found = true,
+		.expected_pending_start = SZ_2G,
+		.expected_pending_end = 3ULL * SZ_1G - 1,
+	},
+	{
+		.name = "pending extent outside search range",
+		.hole_start = 0,
+		.hole_len = SZ_1G,
+		.pending_extent = { SZ_2G, SZ_1G },
+		.expected_found = false,
+	},
+	{
+		.name = "pending extent overlapping end of search range",
+		.hole_start = 0,
+		.hole_len = SZ_2G,
+		.pending_extent = { SZ_1G, SZ_2G },
+		.expected_found = true,
+		.expected_pending_start = SZ_1G,
+		.expected_pending_end = 3ULL * SZ_1G - 1,
+	},
+};
+
+static int test_first_pending_extent(u32 sectorsize, u32 nodesize)
+{
+	struct btrfs_fs_info *fs_info;
+	struct btrfs_device *device;
+	int ret = 0;
+
+	test_msg("running first_pending_extent tests");
+
+	fs_info = btrfs_alloc_dummy_fs_info(nodesize, sectorsize);
+	if (!fs_info) {
+		test_std_err(TEST_ALLOC_FS_INFO);
+		return -ENOMEM;
+	}
+
+	device = btrfs_alloc_dummy_device(fs_info);
+	if (IS_ERR(device)) {
+		test_err("failed to allocate dummy device");
+		ret = PTR_ERR(device);
+		goto out_free_fs_info;
+	}
+
+	device->fs_info = fs_info;
+
+	for (int i = 0; i < ARRAY_SIZE(first_pending_tests); i++) {
+		const struct first_pending_test_case *test_case = &first_pending_tests[i];
+		u64 start = test_case->pending_extent.start;
+		u64 len = test_case->pending_extent.len;
+		u64 pending_start, pending_end;
+		bool found;
+
+		if (len) {
+			btrfs_set_extent_bit(&device->alloc_state,
+					     start, start + len - 1,
+					     CHUNK_ALLOCATED, NULL);
+		}
+
+		mutex_lock(&fs_info->chunk_mutex);
+		found = btrfs_first_pending_extent(device, test_case->hole_start,
+						   test_case->hole_len,
+						   &pending_start, &pending_end);
+		mutex_unlock(&fs_info->chunk_mutex);
+
+		if (found != test_case->expected_found) {
+			test_err("%s: expected found=%d, got found=%d",
+				 test_case->name, test_case->expected_found, found);
+			ret = -EINVAL;
+			goto out_clear_pending_extents;
+		}
+		if (!found)
+			goto out_clear_pending_extents;
+
+		if (pending_start != test_case->expected_pending_start ||
+		    pending_end != test_case->expected_pending_end) {
+			test_err("%s: expected pending [%llu, %llu], got [%llu, %llu]",
+				 test_case->name,
+				 test_case->expected_pending_start,
+				 test_case->expected_pending_end,
+				 pending_start, pending_end);
+			ret = -EINVAL;
+			goto out_clear_pending_extents;
+		}
+
+out_clear_pending_extents:
+		btrfs_clear_extent_bit(&device->alloc_state, 0, (u64)-1,
+				       CHUNK_ALLOCATED, NULL);
+		if (ret)
+			break;
+	}
+
+out_free_fs_info:
+	btrfs_free_dummy_fs_info(fs_info);
+	return ret;
+}
+
+int btrfs_test_chunk_allocation(u32 sectorsize, u32 nodesize)
+{
+	int ret;
+
+	test_msg("running chunk allocation tests");
+
+	ret = test_first_pending_extent(sectorsize, nodesize);
+	if (ret)
+		return ret;
+
+	ret = test_find_hole_in_pending(sectorsize, nodesize);
+	if (ret)
+		return ret;
+
+	return 0;
+}