Re: [PATCH -next v2 1/2] fs/ntfs3: Don't use uni1 uninitialized in ntfs_d_compare()

[Konstantin Komarov]

On 10/21/22 20:10, Nathan Chancellor wrote:
> Ping? This is still breaking our builds in -next...

Thanks for patch, applied!

> On Tue, Oct 04, 2022 at 04:23:58PM -0700, Nathan Chancellor wrote:
> > 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
> > Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
> > Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx>
> > ---
> >
> > v2:
> >      * Pick up Nick's reviewed-by tag.
> > v1: https://lore.kernel.org/20221004144145.1345772-1-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