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, 228 insertions, 0 deletions

diff --git a/fs/jffs2/read.c b/fs/jffs2/read.c
new file mode 100644
index 000000000..0b042b1fc
--- /dev/null
+++ b/fs/jffs2/read.c
@@ -0,0 +1,228 @@
+/*
+ * JFFS2 -- Journalling Flash File System, Version 2.
+ *
+ * Copyright © 2001-2007 Red Hat, Inc.
+ *
+ * Created by David Woodhouse <dwmw2@infradead.org>
+ *
+ * For licensing information, see the file 'LICENCE' in this directory.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/crc32.h>
+#include <linux/pagemap.h>
+#include <linux/mtd/mtd.h>
+#include <linux/compiler.h>
+#include "nodelist.h"
+#include "compr.h"
+
+int jffs2_read_dnode(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
+		     struct jffs2_full_dnode *fd, unsigned char *buf,
+		     int ofs, int len)
+{
+	struct jffs2_raw_inode *ri;
+	size_t readlen;
+	uint32_t crc;
+	unsigned char *decomprbuf = NULL;
+	unsigned char *readbuf = NULL;
+	int ret = 0;
+
+	ri = jffs2_alloc_raw_inode();
+	if (!ri)
+		return -ENOMEM;
+
+	ret = jffs2_flash_read(c, ref_offset(fd->raw), sizeof(*ri), &readlen, (char *)ri);
+	if (ret) {
+		jffs2_free_raw_inode(ri);
+		pr_warn("Error reading node from 0x%08x: %d\n",
+			ref_offset(fd->raw), ret);
+		return ret;
+	}
+	if (readlen != sizeof(*ri)) {
+		jffs2_free_raw_inode(ri);
+		pr_warn("Short read from 0x%08x: wanted 0x%zx bytes, got 0x%zx\n",
+			ref_offset(fd->raw), sizeof(*ri), readlen);
+		return -EIO;
+	}
+	crc = crc32(0, ri, sizeof(*ri)-8);
+
+	jffs2_dbg(1, "Node read from %08x: node_crc %08x, calculated CRC %08x. dsize %x, csize %x, offset %x, buf %p\n",
+		  ref_offset(fd->raw), je32_to_cpu(ri->node_crc),
+		  crc, je32_to_cpu(ri->dsize), je32_to_cpu(ri->csize),
+		  je32_to_cpu(ri->offset), buf);
+	if (crc != je32_to_cpu(ri->node_crc)) {
+		pr_warn("Node CRC %08x != calculated CRC %08x for node at %08x\n",
+			je32_to_cpu(ri->node_crc), crc, ref_offset(fd->raw));
+		ret = -EIO;
+		goto out_ri;
+	}
+	/* There was a bug where we wrote hole nodes out with csize/dsize
+	   swapped. Deal with it */
+	if (ri->compr == JFFS2_COMPR_ZERO && !je32_to_cpu(ri->dsize) &&
+	    je32_to_cpu(ri->csize)) {
+		ri->dsize = ri->csize;
+		ri->csize = cpu_to_je32(0);
+	}
+
+	D1(if(ofs + len > je32_to_cpu(ri->dsize)) {
+			pr_warn("jffs2_read_dnode() asked for %d bytes at %d from %d-byte node\n",
+				len, ofs, je32_to_cpu(ri->dsize));
+		ret = -EINVAL;
+		goto out_ri;
+	});
+
+
+	if (ri->compr == JFFS2_COMPR_ZERO) {
+		memset(buf, 0, len);
+		goto out_ri;
+	}
+
+	/* Cases:
+	   Reading whole node and it's uncompressed - read directly to buffer provided, check CRC.
+	   Reading whole node and it's compressed - read into comprbuf, check CRC and decompress to buffer provided
+	   Reading partial node and it's uncompressed - read into readbuf, check CRC, and copy
+	   Reading partial node and it's compressed - read into readbuf, check checksum, decompress to decomprbuf and copy
+	*/
+	if (ri->compr == JFFS2_COMPR_NONE && len == je32_to_cpu(ri->dsize)) {
+		readbuf = buf;
+	} else {
+		readbuf = kmalloc(je32_to_cpu(ri->csize), GFP_KERNEL);
+		if (!readbuf) {
+			ret = -ENOMEM;
+			goto out_ri;
+		}
+	}
+	if (ri->compr != JFFS2_COMPR_NONE) {
+		if (len < je32_to_cpu(ri->dsize)) {
+			decomprbuf = kmalloc(je32_to_cpu(ri->dsize), GFP_KERNEL);
+			if (!decomprbuf) {
+				ret = -ENOMEM;
+				goto out_readbuf;
+			}
+		} else {
+			decomprbuf = buf;
+		}
+	} else {
+		decomprbuf = readbuf;
+	}
+
+	jffs2_dbg(2, "Read %d bytes to %p\n", je32_to_cpu(ri->csize),
+		  readbuf);
+	ret = jffs2_flash_read(c, (ref_offset(fd->raw)) + sizeof(*ri),
+			       je32_to_cpu(ri->csize), &readlen, readbuf);
+
+	if (!ret && readlen != je32_to_cpu(ri->csize))
+		ret = -EIO;
+	if (ret)
+		goto out_decomprbuf;
+
+	crc = crc32(0, readbuf, je32_to_cpu(ri->csize));
+	if (crc != je32_to_cpu(ri->data_crc)) {
+		pr_warn("Data CRC %08x != calculated CRC %08x for node at %08x\n",
+			je32_to_cpu(ri->data_crc), crc, ref_offset(fd->raw));
+		ret = -EIO;
+		goto out_decomprbuf;
+	}
+	jffs2_dbg(2, "Data CRC matches calculated CRC %08x\n", crc);
+	if (ri->compr != JFFS2_COMPR_NONE) {
+		jffs2_dbg(2, "Decompress %d bytes from %p to %d bytes at %p\n",
+			  je32_to_cpu(ri->csize), readbuf,
+			  je32_to_cpu(ri->dsize), decomprbuf);
+		ret = jffs2_decompress(c, f, ri->compr | (ri->usercompr << 8), readbuf, decomprbuf, je32_to_cpu(ri->csize), je32_to_cpu(ri->dsize));
+		if (ret) {
+			pr_warn("Error: jffs2_decompress returned %d\n", ret);
+			goto out_decomprbuf;
+		}
+	}
+
+	if (len < je32_to_cpu(ri->dsize)) {
+		memcpy(buf, decomprbuf+ofs, len);
+	}
+ out_decomprbuf:
+	if(decomprbuf != buf && decomprbuf != readbuf)
+		kfree(decomprbuf);
+ out_readbuf:
+	if(readbuf != buf)
+		kfree(readbuf);
+ out_ri:
+	jffs2_free_raw_inode(ri);
+
+	return ret;
+}
+
+int jffs2_read_inode_range(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
+			   unsigned char *buf, uint32_t offset, uint32_t len)
+{
+	uint32_t end = offset + len;
+	struct jffs2_node_frag *frag;
+	int ret;
+
+	jffs2_dbg(1, "%s(): ino #%u, range 0x%08x-0x%08x\n",
+		  __func__, f->inocache->ino, offset, offset + len);
+
+	frag = jffs2_lookup_node_frag(&f->fragtree, offset);
+
+	/* XXX FIXME: Where a single physical node actually shows up in two
+	   frags, we read it twice. Don't do that. */
+	/* Now we're pointing at the first frag which overlaps our page
+	 * (or perhaps is before it, if we've been asked to read off the
+	 * end of the file). */
+	while(offset < end) {
+		jffs2_dbg(2, "%s(): offset %d, end %d\n",
+			  __func__, offset, end);
+		if (unlikely(!frag || frag->ofs > offset ||
+			     frag->ofs + frag->size <= offset)) {
+			uint32_t holesize = end - offset;
+			if (frag && frag->ofs > offset) {
+				jffs2_dbg(1, "Eep. Hole in ino #%u fraglist. frag->ofs = 0x%08x, offset = 0x%08x\n",
+					  f->inocache->ino, frag->ofs, offset);
+				holesize = min(holesize, frag->ofs - offset);
+			}
+			jffs2_dbg(1, "Filling non-frag hole from %d-%d\n",
+				  offset, offset + holesize);
+			memset(buf, 0, holesize);
+			buf += holesize;
+			offset += holesize;
+			continue;
+		} else if (unlikely(!frag->node)) {
+			uint32_t holeend = min(end, frag->ofs + frag->size);
+			jffs2_dbg(1, "Filling frag hole from %d-%d (frag 0x%x 0x%x)\n",
+				  offset, holeend, frag->ofs,
+				  frag->ofs + frag->size);
+			memset(buf, 0, holeend - offset);
+			buf += holeend - offset;
+			offset = holeend;
+			frag = frag_next(frag);
+			continue;
+		} else {
+			uint32_t readlen;
+			uint32_t fragofs; /* offset within the frag to start reading */
+
+			fragofs = offset - frag->ofs;
+			readlen = min(frag->size - fragofs, end - offset);
+			jffs2_dbg(1, "Reading %d-%d from node at 0x%08x (%d)\n",
+				  frag->ofs+fragofs,
+				  frag->ofs + fragofs+readlen,
+				  ref_offset(frag->node->raw),
+				  ref_flags(frag->node->raw));
+			ret = jffs2_read_dnode(c, f, frag->node, buf, fragofs + frag->ofs - frag->node->ofs, readlen);
+			jffs2_dbg(2, "node read done\n");
+			if (ret) {
+				jffs2_dbg(1, "%s(): error %d\n",
+					  __func__, ret);
+				memset(buf, 0, readlen);
+				return ret;
+			}
+			buf += readlen;
+			offset += readlen;
+			frag = frag_next(frag);
+			jffs2_dbg(2, "node read was OK. Looping\n");
+		}
+	}
+	return 0;
+}
+