[PATCH -next] fs/ntfs3: Don't use uni1 uninitialized in ntfs_d_compare()

From: Nathan Chancellor
Date: Tue Oct 04 2022 - 10:42:13 EST


Clang warns:

fs/ntfs3/namei.c:445:7: error: variable 'uni1' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
if (toupper(c1) != toupper(c2)) {
^~~~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/ctype.h:64:20: note: expanded from macro 'toupper'
#define toupper(c) __toupper(c)
^
fs/ntfs3/namei.c:487:12: note: uninitialized use occurs here
__putname(uni1);
^~~~
./include/linux/fs.h:2789:65: note: expanded from macro '__putname'
#define __putname(name) kmem_cache_free(names_cachep, (void *)(name))
^~~~
fs/ntfs3/namei.c:445:3: note: remove the 'if' if its condition is always false
if (toupper(c1) != toupper(c2)) {
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/ntfs3/namei.c:434:7: error: variable 'uni1' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
if (!lm--) {
^~~~~
fs/ntfs3/namei.c:487:12: note: uninitialized use occurs here
__putname(uni1);
^~~~
./include/linux/fs.h:2789:65: note: expanded from macro '__putname'
#define __putname(name) kmem_cache_free(names_cachep, (void *)(name))
^~~~
fs/ntfs3/namei.c:434:3: note: remove the 'if' if its condition is always false
if (!lm--) {
^~~~~~~~~~~~
fs/ntfs3/namei.c:430:22: note: initialize the variable 'uni1' to silence this warning
struct cpu_str *uni1, *uni2;
^
= NULL
2 errors generated.

There is no point in calling __putname() in these particular error
paths, as there has been no corresponding __getname() call yet. Just
return directly in these blocks to clear up the warning.

Fixes: a3a956c78efa ("fs/ntfs3: Add option "nocase"")
Link: https://github.com/ClangBuiltLinux/linux/issues/1729
Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx>
---
fs/ntfs3/namei.c | 12 ++++--------
1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/fs/ntfs3/namei.c b/fs/ntfs3/namei.c
index 315763eb05ff..5d3a6ce3f05f 100644
--- a/fs/ntfs3/namei.c
+++ b/fs/ntfs3/namei.c
@@ -431,10 +431,8 @@ static int ntfs_d_compare(const struct dentry *dentry, unsigned int len1,

/* First try fast implementation. */
for (;;) {
- if (!lm--) {
- ret = len1 == len2 ? 0 : 1;
- goto out;
- }
+ if (!lm--)
+ return len1 == len2 ? 0 : 1;

if ((c1 = *n1++) == (c2 = *n2++))
continue;
@@ -442,10 +440,8 @@ static int ntfs_d_compare(const struct dentry *dentry, unsigned int len1,
if (c1 >= 0x80 || c2 >= 0x80)
break;

- if (toupper(c1) != toupper(c2)) {
- ret = 1;
- goto out;
- }
+ if (toupper(c1) != toupper(c2))
+ return 1;
}

/*

base-commit: d45da67caedacd500879de5e649360cc70777af7
--
2.37.3