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, 68 insertions, 0 deletions

diff --git a/block/partitions/check.h b/block/partitions/check.h
new file mode 100644
index 000000000..b0997467b
--- /dev/null
+++ b/block/partitions/check.h
@@ -0,0 +1,68 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/pagemap.h>
+#include <linux/blkdev.h>
+#include <linux/seq_buf.h>
+#include "../blk.h"
+
+/*
+ * add_gd_partition adds a partitions details to the devices partition
+ * description.
+ */
+struct parsed_partitions {
+	struct gendisk *disk;
+	char name[BDEVNAME_SIZE];
+	struct {
+		sector_t from;
+		sector_t size;
+		int flags;
+		bool has_info;
+		struct partition_meta_info info;
+	} *parts;
+	int next;
+	int limit;
+	bool access_beyond_eod;
+	struct seq_buf pp_buf;
+};
+
+typedef struct {
+	struct folio *v;
+} Sector;
+
+void *read_part_sector(struct parsed_partitions *state, sector_t n, Sector *p);
+static inline void put_dev_sector(Sector p)
+{
+	folio_put(p.v);
+}
+
+static inline void
+put_partition(struct parsed_partitions *p, int n, sector_t from, sector_t size)
+{
+	if (n < p->limit) {
+		p->parts[n].from = from;
+		p->parts[n].size = size;
+		seq_buf_printf(&p->pp_buf, " %s%d", p->name, n);
+	}
+}
+
+/* detection routines go here in alphabetical order: */
+int adfspart_check_ADFS(struct parsed_partitions *state);
+int adfspart_check_CUMANA(struct parsed_partitions *state);
+int adfspart_check_EESOX(struct parsed_partitions *state);
+int adfspart_check_ICS(struct parsed_partitions *state);
+int adfspart_check_POWERTEC(struct parsed_partitions *state);
+int aix_partition(struct parsed_partitions *state);
+int amiga_partition(struct parsed_partitions *state);
+int atari_partition(struct parsed_partitions *state);
+int cmdline_partition(struct parsed_partitions *state);
+int efi_partition(struct parsed_partitions *state);
+int ibm_partition(struct parsed_partitions *);
+int karma_partition(struct parsed_partitions *state);
+int ldm_partition(struct parsed_partitions *state);
+int mac_partition(struct parsed_partitions *state);
+int msdos_partition(struct parsed_partitions *state);
+int of_partition(struct parsed_partitions *state);
+int osf_partition(struct parsed_partitions *state);
+int sgi_partition(struct parsed_partitions *state);
+int sun_partition(struct parsed_partitions *state);
+int sysv68_partition(struct parsed_partitions *state);
+int ultrix_partition(struct parsed_partitions *state);