linux-kernel - [PATCH 5.10 475/563] ext4: initialize err_blk before calling __ext4_get_inode

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Date:   Mon, 24 Jan 2022 19:44:00 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Dan Carpenter <dan.carpenter@...cle.com>,
        Harshad Shirwadkar <harshadshirwadkar@...il.com>,
        Theodore Tso <tytso@....edu>, stable@...nel.org
Subject: [PATCH 5.10 475/563] ext4: initialize err_blk before calling __ext4_get_inode_loc

From: Harshad Shirwadkar <harshadshirwadkar@...il.com>

commit c27c29c6af4f3f4ce925a2111c256733c5a5b430 upstream.

It is not guaranteed that __ext4_get_inode_loc will definitely set
err_blk pointer when it returns EIO. To avoid using uninitialized
variables, let's first set err_blk to 0.

Reported-by: Dan Carpenter <dan.carpenter@...cle.com>
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@...il.com>
Link: https://lore.kernel.org/r/20211201163421.2631661-1-harshads@google.com
Signed-off-by: Theodore Ts'o <tytso@....edu>
Cc: stable@...nel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 fs/ext4/inode.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4445,7 +4445,7 @@ has_buffer:
 static int __ext4_get_inode_loc_noinmem(struct inode *inode,
 					struct ext4_iloc *iloc)
 {
-	ext4_fsblk_t err_blk;
+	ext4_fsblk_t err_blk = 0;
 	int ret;
 
 	ret = __ext4_get_inode_loc(inode->i_sb, inode->i_ino, iloc, 0,
@@ -4460,7 +4460,7 @@ static int __ext4_get_inode_loc_noinmem(
 
 int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
 {
-	ext4_fsblk_t err_blk;
+	ext4_fsblk_t err_blk = 0;
 	int ret;
 
 	/* We have all inode data except xattrs in memory here. */