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, 293 insertions, 0 deletions

diff --git a/fs/udf/truncate.c b/fs/udf/truncate.c
new file mode 100644
index 000000000..0990f94b8
--- /dev/null
+++ b/fs/udf/truncate.c
@@ -0,0 +1,293 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * truncate.c
+ *
+ * PURPOSE
+ *	Truncate handling routines for the OSTA-UDF(tm) filesystem.
+ *
+ * COPYRIGHT
+ *  (C) 1999-2004 Ben Fennema
+ *  (C) 1999 Stelias Computing Inc
+ *
+ * HISTORY
+ *
+ *  02/24/99 blf  Created.
+ *
+ */
+
+#include "udfdecl.h"
+#include <linux/fs.h>
+#include <linux/mm.h>
+
+#include "udf_i.h"
+#include "udf_sb.h"
+
+static void extent_trunc(struct inode *inode, struct extent_position *epos,
+			 struct kernel_lb_addr *eloc, int8_t etype, uint32_t elen,
+			 uint32_t nelen)
+{
+	struct kernel_lb_addr neloc = {};
+	int last_block = (elen + inode->i_sb->s_blocksize - 1) >>
+		inode->i_sb->s_blocksize_bits;
+	int first_block = (nelen + inode->i_sb->s_blocksize - 1) >>
+		inode->i_sb->s_blocksize_bits;
+
+	if (nelen) {
+		if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
+			udf_free_blocks(inode->i_sb, inode, eloc, 0,
+					last_block);
+			etype = (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30);
+		} else
+			neloc = *eloc;
+		nelen = (etype << 30) | nelen;
+	}
+
+	if (elen != nelen) {
+		udf_write_aext(inode, epos, &neloc, nelen, 0);
+		if (last_block > first_block) {
+			if (etype == (EXT_RECORDED_ALLOCATED >> 30))
+				mark_inode_dirty(inode);
+
+			if (etype != (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
+				udf_free_blocks(inode->i_sb, inode, eloc,
+						first_block,
+						last_block - first_block);
+		}
+	}
+}
+
+/*
+ * Truncate the last extent to match i_size. This function assumes
+ * that preallocation extent is already truncated.
+ */
+void udf_truncate_tail_extent(struct inode *inode)
+{
+	struct extent_position epos = {};
+	struct kernel_lb_addr eloc;
+	uint32_t elen, nelen;
+	uint64_t lbcount = 0;
+	int8_t etype = -1, netype;
+	int adsize;
+	struct udf_inode_info *iinfo = UDF_I(inode);
+	int ret;
+
+	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
+	    inode->i_size == iinfo->i_lenExtents)
+		return;
+	/* Are we going to delete the file anyway? */
+	if (inode->i_nlink == 0)
+		return;
+
+	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
+		adsize = sizeof(struct short_ad);
+	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
+		adsize = sizeof(struct long_ad);
+	else
+		BUG();
+
+	/* Find the last extent in the file */
+	while (1) {
+		ret = udf_next_aext(inode, &epos, &eloc, &elen, &netype, 1);
+		if (ret <= 0)
+			break;
+		etype = netype;
+		lbcount += elen;
+		if (lbcount > inode->i_size) {
+			if (lbcount - inode->i_size >= inode->i_sb->s_blocksize)
+				udf_warn(inode->i_sb,
+					 "Too long extent after EOF in inode %u: i_size: %lld lbcount: %lld extent %u+%u\n",
+					 (unsigned)inode->i_ino,
+					 (long long)inode->i_size,
+					 (long long)lbcount,
+					 (unsigned)eloc.logicalBlockNum,
+					 (unsigned)elen);
+			nelen = elen - (lbcount - inode->i_size);
+			epos.offset -= adsize;
+			extent_trunc(inode, &epos, &eloc, etype, elen, nelen);
+			epos.offset += adsize;
+			if (udf_next_aext(inode, &epos, &eloc, &elen,
+					  &netype, 1) > 0)
+				udf_err(inode->i_sb,
+					"Extent after EOF in inode %u\n",
+					(unsigned)inode->i_ino);
+			break;
+		}
+	}
+	/* This inode entry is in-memory only and thus we don't have to mark
+	 * the inode dirty */
+	if (ret >= 0)
+		iinfo->i_lenExtents = inode->i_size;
+	brelse(epos.bh);
+}
+
+void udf_discard_prealloc(struct inode *inode)
+{
+	struct extent_position epos = {};
+	struct extent_position prev_epos = {};
+	struct kernel_lb_addr eloc;
+	uint32_t elen;
+	uint64_t lbcount = 0;
+	int8_t etype = -1;
+	struct udf_inode_info *iinfo = UDF_I(inode);
+	int bsize = i_blocksize(inode);
+	int8_t tmpetype = -1;
+	int ret;
+
+	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
+	    ALIGN(inode->i_size, bsize) == ALIGN(iinfo->i_lenExtents, bsize))
+		return;
+
+	epos.block = iinfo->i_location;
+
+	/* Find the last extent in the file */
+	while (1) {
+		ret = udf_next_aext(inode, &epos, &eloc, &elen, &tmpetype, 0);
+		if (ret < 0)
+			goto out;
+		if (ret == 0)
+			break;
+		brelse(prev_epos.bh);
+		prev_epos = epos;
+		if (prev_epos.bh)
+			get_bh(prev_epos.bh);
+
+		ret = udf_next_aext(inode, &epos, &eloc, &elen, &etype, 1);
+		if (ret < 0)
+			goto out;
+		lbcount += elen;
+	}
+
+	if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
+		lbcount -= elen;
+		udf_delete_aext(inode, prev_epos, NULL);
+		udf_free_blocks(inode->i_sb, inode, &eloc, 0,
+				DIV_ROUND_UP(elen, bsize));
+	}
+	/* This inode entry is in-memory only and thus we don't have to mark
+	 * the inode dirty */
+	iinfo->i_lenExtents = lbcount;
+out:
+	brelse(epos.bh);
+	brelse(prev_epos.bh);
+}
+
+static void udf_update_alloc_ext_desc(struct inode *inode,
+				      struct extent_position *epos,
+				      u32 lenalloc)
+{
+	struct super_block *sb = inode->i_sb;
+	struct udf_sb_info *sbi = UDF_SB(sb);
+
+	struct allocExtDesc *aed = (struct allocExtDesc *) (epos->bh->b_data);
+	int len = sizeof(struct allocExtDesc);
+
+	aed->lengthAllocDescs =	cpu_to_le32(lenalloc);
+	if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) || sbi->s_udfrev >= 0x0201)
+		len += lenalloc;
+
+	udf_update_tag(epos->bh->b_data, len);
+	mmb_mark_buffer_dirty(epos->bh, &UDF_I(inode)->i_metadata_bhs);
+}
+
+/*
+ * Truncate extents of inode to inode->i_size. This function can be used only
+ * for making file shorter. For making file longer, udf_extend_file() has to
+ * be used.
+ */
+int udf_truncate_extents(struct inode *inode)
+{
+	struct extent_position epos;
+	struct kernel_lb_addr eloc, neloc = {};
+	uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc;
+	int8_t etype;
+	struct super_block *sb = inode->i_sb;
+	sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset;
+	loff_t byte_offset;
+	int adsize;
+	struct udf_inode_info *iinfo = UDF_I(inode);
+	int ret = 0;
+
+	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
+		adsize = sizeof(struct short_ad);
+	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
+		adsize = sizeof(struct long_ad);
+	else
+		BUG();
+
+	ret = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset, &etype);
+	if (ret < 0)
+		return ret;
+	byte_offset = (offset << sb->s_blocksize_bits) +
+		(inode->i_size & (sb->s_blocksize - 1));
+	if (ret == 0) {
+		/* We should extend the file? */
+		WARN_ON(byte_offset);
+		return 0;
+	}
+	epos.offset -= adsize;
+	extent_trunc(inode, &epos, &eloc, etype, elen, byte_offset);
+	epos.offset += adsize;
+	if (byte_offset)
+		lenalloc = epos.offset;
+	else
+		lenalloc = epos.offset - adsize;
+
+	if (!epos.bh)
+		lenalloc -= udf_file_entry_alloc_offset(inode);
+	else
+		lenalloc -= sizeof(struct allocExtDesc);
+
+	while ((ret = udf_current_aext(inode, &epos, &eloc,
+				       &elen, &etype, 0)) > 0) {
+		if (etype == (EXT_NEXT_EXTENT_ALLOCDESCS >> 30)) {
+			udf_write_aext(inode, &epos, &neloc, nelen, 0);
+			if (indirect_ext_len) {
+				/* We managed to free all extents in the
+				 * indirect extent - free it too */
+				BUG_ON(!epos.bh);
+				udf_free_blocks(sb, NULL, &epos.block,
+						0, indirect_ext_len);
+			} else if (!epos.bh) {
+				iinfo->i_lenAlloc = lenalloc;
+				mark_inode_dirty(inode);
+			} else
+				udf_update_alloc_ext_desc(inode,
+						&epos, lenalloc);
+			brelse(epos.bh);
+			epos.offset = sizeof(struct allocExtDesc);
+			epos.block = eloc;
+			epos.bh = sb_bread(sb,
+					udf_get_lb_pblock(sb, &eloc, 0));
+			/* Error reading indirect block? */
+			if (!epos.bh)
+				return -EIO;
+			if (elen)
+				indirect_ext_len =
+					(elen + sb->s_blocksize - 1) >>
+					sb->s_blocksize_bits;
+			else
+				indirect_ext_len = 1;
+		} else {
+			extent_trunc(inode, &epos, &eloc, etype, elen, 0);
+			epos.offset += adsize;
+		}
+	}
+
+	if (ret < 0) {
+		brelse(epos.bh);
+		return ret;
+	}
+
+	if (indirect_ext_len) {
+		BUG_ON(!epos.bh);
+		udf_free_blocks(sb, NULL, &epos.block, 0, indirect_ext_len);
+	} else if (!epos.bh) {
+		iinfo->i_lenAlloc = lenalloc;
+		mark_inode_dirty(inode);
+	} else
+		udf_update_alloc_ext_desc(inode, &epos, lenalloc);
+	iinfo->i_lenExtents = inode->i_size;
+
+	brelse(epos.bh);
+	return 0;
+}