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, 52 insertions, 0 deletions

diff --git a/fs/gfs2/trans.h b/fs/gfs2/trans.h
new file mode 100644
index 000000000..790c55f59
--- /dev/null
+++ b/fs/gfs2/trans.h
@@ -0,0 +1,52 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
+ * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
+ */
+
+#ifndef __TRANS_DOT_H__
+#define __TRANS_DOT_H__
+
+#include <linux/buffer_head.h>
+struct gfs2_sbd;
+struct gfs2_rgrpd;
+struct gfs2_glock;
+
+#define RES_DINODE	1
+#define RES_INDIRECT	1
+#define RES_JDATA	1
+#define RES_DATA	1
+#define RES_LEAF	1
+#define RES_RG_HDR	1
+#define RES_RG_BIT	2
+#define RES_EATTR	1
+#define RES_STATFS	1
+#define RES_QUOTA	2
+
+/* reserve either the number of blocks to be allocated plus the rg header
+ * block, or all of the blocks in the rg, whichever is smaller */
+static inline unsigned int gfs2_rg_blocks(const struct gfs2_inode *ip, unsigned requested)
+{
+	struct gfs2_rgrpd *rgd = ip->i_res.rs_rgd;
+
+	if (requested < rgd->rd_length)
+		return requested + 1;
+	return rgd->rd_length;
+}
+
+int __gfs2_trans_begin(struct gfs2_trans *tr, struct gfs2_sbd *sdp,
+		       unsigned int blocks, unsigned int revokes,
+		       unsigned long ip);
+int gfs2_trans_begin(struct gfs2_sbd *sdp, unsigned int blocks,
+		     unsigned int revokes);
+
+void gfs2_trans_end(struct gfs2_sbd *sdp);
+void gfs2_trans_add_data(struct gfs2_glock *gl, struct buffer_head *bh);
+void gfs2_trans_add_databufs(struct gfs2_glock *gl, struct folio *folio,
+			     size_t from, size_t len);
+void gfs2_trans_add_meta(struct gfs2_glock *gl, struct buffer_head *bh);
+void gfs2_trans_add_revoke(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd);
+void gfs2_trans_remove_revoke(struct gfs2_sbd *sdp, u64 blkno, unsigned int len);
+void gfs2_trans_free(struct gfs2_sbd *sdp, struct gfs2_trans *tr);
+
+#endif /* __TRANS_DOT_H__ */