linux-kernel - [PATCH AUTOSEL for 4.14 035/161] ubifs: Fix uninitialized variable in search_dh

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Message-ID: <20180409001936.162706-35-alexander.levin@microsoft.com>
Date:   Mon, 9 Apr 2018 00:20:12 +0000
From:   Sasha Levin <Alexander.Levin@...rosoft.com>
To:     "stable@...r.kernel.org" <stable@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     Geert Uytterhoeven <geert@...ux-m68k.org>,
        Richard Weinberger <richard@....at>,
        Sasha Levin <Alexander.Levin@...rosoft.com>
Subject: [PATCH AUTOSEL for 4.14 035/161] ubifs: Fix uninitialized variable in
 search_dh_cookie()

From: Geert Uytterhoeven <geert@...ux-m68k.org>

[ Upstream commit c877154d307f4a91e0b5b85b75535713dab945ae ]

fs/ubifs/tnc.c: In function ‘search_dh_cookie’:
fs/ubifs/tnc.c:1893: warning: ‘err’ is used uninitialized in this function

Indeed, err is always used uninitialized.

According to an original review comment from Hyunchul, acknowledged by
Richard, err should be initialized to -ENOENT to avoid the first call to
tnc_next().  But we can achieve the same by reordering the code.

Fixes: 781f675e2d7e ("ubifs: Fix unlink code wrt. double hash lookups")
Reported-by: Hyunchul Lee <hyc.lee@...il.com>
Signed-off-by: Geert Uytterhoeven <geert@...ux-m68k.org>
Signed-off-by: Richard Weinberger <richard@....at>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
---
 fs/ubifs/tnc.c | 21 +++++++--------------
 1 file changed, 7 insertions(+), 14 deletions(-)

diff --git a/fs/ubifs/tnc.c b/fs/ubifs/tnc.c
index 0a213dcba2a1..ba3d0e0f8615 100644
--- a/fs/ubifs/tnc.c
+++ b/fs/ubifs/tnc.c
@@ -1890,35 +1890,28 @@ static int search_dh_cookie(struct ubifs_info *c, const union ubifs_key *key,
 	union ubifs_key *dkey;
 
 	for (;;) {
-		if (!err) {
-			err = tnc_next(c, &znode, n);
-			if (err)
-				goto out;
-		}
-
 		zbr = &znode->zbranch[*n];
 		dkey = &zbr->key;
 
 		if (key_inum(c, dkey) != key_inum(c, key) ||
 		    key_type(c, dkey) != key_type(c, key)) {
-			err = -ENOENT;
-			goto out;
+			return -ENOENT;
 		}
 
 		err = tnc_read_hashed_node(c, zbr, dent);
 		if (err)
-			goto out;
+			return err;
 
 		if (key_hash(c, key) == key_hash(c, dkey) &&
 		    le32_to_cpu(dent->cookie) == cookie) {
 			*zn = znode;
-			goto out;
+			return 0;
 		}
-	}
-
-out:
 
-	return err;
+		err = tnc_next(c, &znode, n);
+		if (err)
+			return err;
+	}
 }
 
 static int do_lookup_dh(struct ubifs_info *c, const union ubifs_key *key,
-- 
2.15.1