From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CD5E84683; Tue, 4 Oct 2022 23:26:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1FA2EC433D6; Tue, 4 Oct 2022 23:26:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1664925972; bh=hg5t47yAStpJb95gYWxc3f1CRgOEIT4RkUFnxKN6WNQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=uM7FOR41lUjVTQLYowd2dzmS5mPYqsJVz6/XGBli3WjJT+fNQQmJSAOa/TvozpcBp RwwpHb2WKSIgyfnoCTsNhV7QNE6iLN1MIhcvckrzByCWfhedpYdolXoCr4aA9A5mbQ FppFMByjZE00QhMzKtfvzwAgFYUYaOze5xHXpYNo4ATySt2B0VswrPsDvUBdOPWYsk VGOb17Ae9c4m9+tZ3RD5psSECYR0n4rZF5a28tXWzgNkpsruxLZd9/CLNm8MPv4X6b RKE+i+1byKNNbpU12FaUxW7A+xUOluEe8gdbZne/zMQuCieFesRtp+w0yHs7hqtX0u /CIf9NheBMM9g== Date: Tue, 4 Oct 2022 16:26:10 -0700 From: Nathan Chancellor To: Nick Desaulniers Cc: Konstantin Komarov , Tom Rix , ntfs3@lists.linux.dev, llvm@lists.linux.dev, patches@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH -next] fs/ntfs3: Don't use uni1 uninitialized in ntfs_d_compare() Message-ID: References: <20221004144145.1345772-1-nathan@kernel.org> Precedence: bulk X-Mailing-List: ntfs3@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Oct 04, 2022 at 03:56:45PM -0700, Nick Desaulniers wrote: > On Tue, Oct 4, 2022 at 7:42 AM 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 > > Signed-off-by: Nathan Chancellor > > --- > > 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 > > 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