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s=default; t=1600234918; bh=hSP4gRwVEWhysa34HuwuUeUWtwGLR+7qBuvWJ/US/xI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=z6DxVqWLpWKYFixD+gwLxBRh1iUCN5ANUHZOZ773rz+A3XDsFwA3/qz5POT3/X5pv MEO3ATs0i1zhe9mEIRHRP3dHjUStgDnGX5eRK4iG4LawIRdKytaRh1Wlvx2gNGSION MwoogpUb3sI4lAbZ2Mi8BbgtPd4HPKJXYKsFyazc= Date: Tue, 15 Sep 2020 22:41:57 -0700 From: Eric Biggers To: Anant Thazhemadam Message-ID: <20200916054157.GC825@sol.localdomain> References: <20200916052657.18683-1-anant.thazhemadam@gmail.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200916052657.18683-1-anant.thazhemadam@gmail.com> Cc: linux-fsdevel@vger.kernel.org, syzbot+4191a44ad556eacc1a7a@syzkaller.appspotmail.com, linux-kernel-mentees@lists.linuxfoundation.org, Alexander Viro , linux-kernel@vger.kernel.org Subject: Re: [Linux-kernel-mentees] [PATCH] fs: fix KMSAN uninit-value bug by initializing nd in do_file_open_root X-BeenThere: linux-kernel-mentees@lists.linuxfoundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-kernel-mentees-bounces@lists.linuxfoundation.org Sender: "Linux-kernel-mentees" On Wed, Sep 16, 2020 at 10:56:56AM +0530, Anant Thazhemadam wrote: > The KMSAN bug report for the bug indicates that there exists; > Local variable ----nd@do_file_open_root created at: > do_file_open_root+0xa4/0xb40 fs/namei.c:3385 > do_file_open_root+0xa4/0xb40 fs/namei.c:3385 > > Initializing nd fixes this issue, and doesn't break anything else either > > Fixes: https://syzkaller.appspot.com/bug?extid=4191a44ad556eacc1a7a > Reported-by: syzbot+4191a44ad556eacc1a7a@syzkaller.appspotmail.com > Tested-by: syzbot+4191a44ad556eacc1a7a@syzkaller.appspotmail.com > Signed-off-by: Anant Thazhemadam > --- > fs/namei.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/namei.c b/fs/namei.c > index e99e2a9da0f7..b27382586209 100644 > --- a/fs/namei.c > +++ b/fs/namei.c > @@ -3404,7 +3404,7 @@ struct file *do_filp_open(int dfd, struct filename *pathname, > struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt, > const char *name, const struct open_flags *op) > { > - struct nameidata nd; > + struct nameidata nd = {}; > struct file *file; > struct filename *filename; > int flags = op->lookup_flags | LOOKUP_ROOT; Looking at the actual KMSAN report, it looks like it's nameidata::dir_mode or nameidata::dir_uid that is uninitialized. You need to figure out the correct solution, not just blindly initialize with zeroes -- that could hide a bug. Is there a bug that is preventing these fields from being initialized to the correct values, are these fields being used when they shouldn't be, etc... - Eric _______________________________________________ Linux-kernel-mentees mailing list Linux-kernel-mentees@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees