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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id v5sm14778297pfm.22.2019.06.11.11.44.54 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 11 Jun 2019 11:44:54 -0700 (PDT) Date: Tue, 11 Jun 2019 11:44:53 -0700 From: Kees Cook To: Greg Kroah-Hartman Cc: Arnd Bergmann , linux-kernel@vger.kernel.org Subject: Re: [PATCH] lkdtm: no need to check return value of debugfs_create functions Message-ID: <201906111144.3E05EAA80@keescook> References: <20190611183213.GA31645@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190611183213.GA31645@kroah.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 11, 2019 at 08:32:13PM +0200, Greg Kroah-Hartman wrote: > When calling debugfs functions, there is no need to ever check the > return value. The function can work or not, but the code logic should > never do something different based on this. What is the user-visible feedback when, say, debugfs_create_file() fails? And what happens when debugfs_create_file() passes in a NULL root? -Kees > > Cc: Kees Cook > Cc: Arnd Bergmann > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Greg Kroah-Hartman > --- > drivers/misc/lkdtm/core.c | 13 ++----------- > 1 file changed, 2 insertions(+), 11 deletions(-) > > diff --git a/drivers/misc/lkdtm/core.c b/drivers/misc/lkdtm/core.c > index 1972dad966f5..bae3b3763f3e 100644 > --- a/drivers/misc/lkdtm/core.c > +++ b/drivers/misc/lkdtm/core.c > @@ -429,22 +429,13 @@ static int __init lkdtm_module_init(void) > > /* Register debugfs interface */ > lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL); > - if (!lkdtm_debugfs_root) { > - pr_err("creating root dir failed\n"); > - return -ENODEV; > - } > > /* Install debugfs trigger files. */ > for (i = 0; i < ARRAY_SIZE(crashpoints); i++) { > struct crashpoint *cur = &crashpoints[i]; > - struct dentry *de; > > - de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root, > - cur, &cur->fops); > - if (de == NULL) { > - pr_err("could not create crashpoint %s\n", cur->name); > - goto out_err; > - } > + debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root, cur, > + &cur->fops); > } > > /* Install crashpoint if one was selected. */ > -- > 2.22.0 > -- Kees Cook