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Subject[PATCH] ubifs: Fix uninitialized variable in search_dh_cookie()
Date
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.

Reported-by: Hyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
Compile-tested only.

Still needed in v4.14-rc1, so I'm sending out the patch I wrote in July.
This avoids initializing err at the top, so we don't loose the ability to
catch future uninitialized use.
---
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 0a213dcba2a1f0f5..ba3d0e0f86151e53 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,
--
2.7.4
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