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* [PATCH -next] fs/ntfs3: Don't use uni1 uninitialized in ntfs_d_compare()
@ 2022-10-04 14:41 Nathan Chancellor
  2022-10-04 22:56 ` Nick Desaulniers
  0 siblings, 1 reply; 3+ messages in thread
From: Nathan Chancellor @ 2022-10-04 14:41 UTC (permalink / raw)
  To: Konstantin Komarov
  Cc: Nick Desaulniers, Tom Rix, ntfs3, llvm, patches, linux-kernel,
	Nathan Chancellor

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@kernel.org>
---
 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


^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [PATCH -next] fs/ntfs3: Don't use uni1 uninitialized in ntfs_d_compare()
  2022-10-04 14:41 [PATCH -next] fs/ntfs3: Don't use uni1 uninitialized in ntfs_d_compare() Nathan Chancellor
@ 2022-10-04 22:56 ` Nick Desaulniers
  2022-10-04 23:26   ` Nathan Chancellor
  0 siblings, 1 reply; 3+ messages in thread
From: Nick Desaulniers @ 2022-10-04 22:56 UTC (permalink / raw)
  To: Nathan Chancellor
  Cc: Konstantin Komarov, Tom Rix, ntfs3, llvm, patches, linux-kernel

On Tue, Oct 4, 2022 at 7:42 AM Nathan Chancellor <nathan@kernel.org> 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
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> ---
>  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;

I know the code originally used this, but I can't help but look at
this and think that it should be:

return len1 != len2;

Do you mind cleaning it up while you're here?

Otherwise LGTM;

Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

You may retain my RB tag whether you send that suggestion in a v2 or not.

>
>                 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
>


-- 
Thanks,
~Nick Desaulniers

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH -next] fs/ntfs3: Don't use uni1 uninitialized in ntfs_d_compare()
  2022-10-04 22:56 ` Nick Desaulniers
@ 2022-10-04 23:26   ` Nathan Chancellor
  0 siblings, 0 replies; 3+ messages in thread
From: Nathan Chancellor @ 2022-10-04 23:26 UTC (permalink / raw)
  To: Nick Desaulniers
  Cc: Konstantin Komarov, Tom Rix, ntfs3, llvm, patches, linux-kernel

On Tue, Oct 04, 2022 at 03:56:45PM -0700, Nick Desaulniers wrote:
> On Tue, Oct 4, 2022 at 7:42 AM Nathan Chancellor <nathan@kernel.org> 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
> > Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> > ---
> >  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;
> 
> I know the code originally used this, but I can't help but look at
> this and think that it should be:
> 
> return len1 != len2;
> 
> Do you mind cleaning it up while you're here?
> 
> Otherwise LGTM;
> 
> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
> 
> You may retain my RB tag whether you send that suggestion in a v2 or not.

I sent a v2 but I kept the changes separate:

https://lore.kernel.org/20221004232359.285685-1-nathan@kernel.org/
https://lore.kernel.org/20221004232359.285685-2-nathan@kernel.org/

Thanks for taking a look!

> >
> >                 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
> >
> 
> 
> -- 
> Thanks,
> ~Nick Desaulniers

^ permalink raw reply	[flat|nested] 3+ messages in thread

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2022-10-04 14:41 [PATCH -next] fs/ntfs3: Don't use uni1 uninitialized in ntfs_d_compare() Nathan Chancellor
2022-10-04 22:56 ` Nick Desaulniers
2022-10-04 23:26   ` Nathan Chancellor

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