linux-kernel - [PATCH 1/2] xfs: zero initialize highstale and lowstale in xfs_dir2_leaf

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Message-ID: <20190311161948.GC4359@magnolia>
Date:   Mon, 11 Mar 2019 09:19:48 -0700
From:   "Darrick J. Wong" <darrick.wong@...cle.com>
To:     linux-xfs@...r.kernel.org
Cc:     Nathan Chancellor <natechancellor@...il.com>,
        linux-kernel@...r.kernel.org,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        clang-built-linux@...glegroups.com
Subject: [PATCH 1/2] xfs: zero initialize highstale and lowstale in
 xfs_dir2_leaf_addname

From: Darrick J. Wong <darrick.wong@...cle.com>

Smatch complains about the following:

fs/xfs/libxfs/xfs_dir2_leaf.c:848 xfs_dir2_leaf_addname() error:
uninitialized symbol 'lowstale'.

fs/xfs/libxfs/xfs_dir2_leaf.c:849 xfs_dir2_leaf_addname() error:
uninitialized symbol 'highstale'.

I don't think there's any incorrect behavior associated with the
uninitialized variable, but as the author of the previous zero-init
patch points out, it's best not to be passing around pointers to
uninitialized stack areas.

Signed-off-by: Darrick J. Wong <darrick.wong@...cle.com>
---
 fs/xfs/libxfs/xfs_dir2_leaf.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_dir2_leaf.c b/fs/xfs/libxfs/xfs_dir2_leaf.c
index 9a3767818c50..2abf945e5844 100644
--- a/fs/xfs/libxfs/xfs_dir2_leaf.c
+++ b/fs/xfs/libxfs/xfs_dir2_leaf.c
@@ -574,7 +574,7 @@ xfs_dir2_leaf_addname(
 	xfs_dir2_data_unused_t	*dup;		/* data unused entry */
 	int			error;		/* error return value */
 	int			grown;		/* allocated new data block */
-	int			highstale;	/* index of next stale leaf */
+	int			highstale = 0;	/* index of next stale leaf */
 	int			i;		/* temporary, index */
 	int			index;		/* leaf table position */
 	struct xfs_buf		*lbp;		/* leaf's buffer */
@@ -583,7 +583,7 @@ xfs_dir2_leaf_addname(
 	xfs_dir2_leaf_entry_t	*lep;		/* leaf entry table pointer */
 	int			lfloglow;	/* low leaf logging index */
 	int			lfloghigh;	/* high leaf logging index */
-	int			lowstale;	/* index of prev stale leaf */
+	int			lowstale = 0;	/* index of prev stale leaf */
 	xfs_dir2_leaf_tail_t	*ltp;		/* leaf tail pointer */
 	int			needbytes;	/* leaf block bytes needed */
 	int			needlog;	/* need to log data header */