Fix the issue detected by the smatch tool.

fs/ext4/inode.c:3583 ext4_map_blocks_atomic_write_slow() error: uninitialized symbol 'next_pblk'.
fs/ext4/namei.c:1776 ext4_lookup() error: uninitialized symbol 'de'.
fs/ext4/namei.c:1829 ext4_get_parent() error: uninitialized symbol 'de'.
fs/ext4/namei.c:3162 ext4_rmdir() error: uninitialized symbol 'de'.
fs/ext4/namei.c:3242 __ext4_unlink() error: uninitialized symbol 'de'.
fs/ext4/namei.c:3697 ext4_find_delete_entry() error: uninitialized symbol 'de'.

These changes enhance code clarity, address static analysis tool errors.

Signed-off-by: Ranganath V N <vnranganath.20@gmail.com>
---

v2:
corrected the kernel test robot noticed build errors.

 fs/ext4/inode.c |  2 +-
 fs/ext4/namei.c | 10 +++++-----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 5b7a15db4953..f20db3f4ef68 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3544,7 +3544,7 @@ static int ext4_map_blocks_atomic_write_slow(handle_t *handle,
 	ext4_lblk_t m_lblk = map->m_lblk;
 	unsigned int m_len = map->m_len;
 	unsigned int mapped_len = 0, m_flags = 0;
-	ext4_fsblk_t next_pblk;
+	ext4_fsblk_t next_pblk = 0;
 	bool check_next_pblk = false;
 	int ret = 0;
 
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 2cd36f59c9e3..045616033515 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1762,7 +1762,7 @@ static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
 static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
 {
 	struct inode *inode;
-	struct ext4_dir_entry_2 *de;
+	struct ext4_dir_entry_2 *de = NULL;
 	struct buffer_head *bh;
 
 	if (dentry->d_name.len > EXT4_NAME_LEN)
@@ -1818,7 +1818,7 @@ static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsi
 struct dentry *ext4_get_parent(struct dentry *child)
 {
 	__u32 ino;
-	struct ext4_dir_entry_2 * de;
+	struct ext4_dir_entry_2 * de = NULL;
 	struct buffer_head *bh;
 
 	bh = ext4_find_entry(d_inode(child), &dotdot_name, &de, NULL);
@@ -3133,7 +3133,7 @@ static int ext4_rmdir(struct inode *dir, struct dentry *dentry)
 	int retval;
 	struct inode *inode;
 	struct buffer_head *bh;
-	struct ext4_dir_entry_2 *de;
+	struct ext4_dir_entry_2 *de = NULL;
 	handle_t *handle = NULL;
 
 	retval = ext4_emergency_state(dir->i_sb);
@@ -3224,7 +3224,7 @@ int __ext4_unlink(struct inode *dir, const struct qstr *d_name,
 {
 	int retval = -ENOENT;
 	struct buffer_head *bh;
-	struct ext4_dir_entry_2 *de;
+	struct ext4_dir_entry_2 *de = NULL;
 	handle_t *handle;
 	int skip_remove_dentry = 0;
 
@@ -3688,7 +3688,7 @@ static int ext4_find_delete_entry(handle_t *handle, struct inode *dir,
 {
 	int retval = -ENOENT;
 	struct buffer_head *bh;
-	struct ext4_dir_entry_2 *de;
+	struct ext4_dir_entry_2 *de = NULL;
 
 	bh = ext4_find_entry(dir, d_name, &de, NULL);
 	if (IS_ERR(bh))
-- 
2.43.0

On Sat, 11 Oct 2025 12:08:29 +0530, Ranganath V N wrote:
> Fix the issue detected by the smatch tool.
> 
> fs/ext4/inode.c:3583 ext4_map_blocks_atomic_write_slow() error: uninitialized symbol 'next_pblk'.
> fs/ext4/namei.c:1776 ext4_lookup() error: uninitialized symbol 'de'.
> fs/ext4/namei.c:1829 ext4_get_parent() error: uninitialized symbol 'de'.
> fs/ext4/namei.c:3162 ext4_rmdir() error: uninitialized symbol 'de'.
> fs/ext4/namei.c:3242 __ext4_unlink() error: uninitialized symbol 'de'.
> fs/ext4/namei.c:3697 ext4_find_delete_entry() error: uninitialized symbol 'de'.
> 
> [...]

Applied, thanks!

[1/1] fs: ext4: fix uninitialized symbols
      commit: 6640d552185f7c11235c64a832004db9af119b2d

Best regards,
-- 
Theodore Ts'o <tytso@mit.edu>

On Sat, Oct 11, 2025 at 12:08:29PM +0530, Ranganath V N wrote:
> Fix the issue detected by the smatch tool.
> 
> fs/ext4/inode.c:3583 ext4_map_blocks_atomic_write_slow() error: uninitialized symbol 'next_pblk'.

This one is valid, and I agree with your proposed changed.  (Although
the worst that will happen is that in case of an ENOSPC error comined
with a corrpted file system the warning message may print an
uninitialized value.  So not a big eal, but we might as well fix it.)

> fs/ext4/namei.c:1776 ext4_lookup() error: uninitialized symbol 'de'.

This is a false positive for smatch.  There isn't actualy a prolem
here, because all of these funtions are calling ext4_find_entry() or
ext4_lookup_entry(), and the callers will not try to dereference the
pointer passed into *res_dir ('de') if the function has either
returned NULL or an ERR_PTR(), and that's in fact correct.

I don't especially mind the fix (but I do wish smatch could be
smarter).  Out of curiosity, if we move the *res_dir = NULL from
__ext4_find_entry() and move it so it's unconditionally set in
ext4_find_entry() and ext4_lookup_entry(), is that sufficient to make
smatch stop complaining?

					- Ted