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[209.85.222.46]) by smtp.gmail.com with ESMTPSA id b9sm89814vsp.24.2020.06.29.14.16.51 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 29 Jun 2020 14:16:51 -0700 (PDT) Received: by mail-ua1-f46.google.com with SMTP id q15so5595845uap.4 for ; Mon, 29 Jun 2020 14:16:51 -0700 (PDT) X-Received: by 2002:ab0:29c1:: with SMTP id i1mr12275723uaq.120.1593465411383; Mon, 29 Jun 2020 14:16:51 -0700 (PDT) MIME-Version: 1.0 References: <20200629153756.cxg74nec3repa4lu@holly.lan> <20200629205012.3263-1-cengiz@kernel.wtf> In-Reply-To: <20200629205012.3263-1-cengiz@kernel.wtf> From: Doug Anderson Date: Mon, 29 Jun 2020 14:16:39 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v2] kdb: remove unnecessary null check of dbg_io_ops To: Cengiz Can Cc: Daniel Thompson , Andy Shevchenko , Jason Wessel , kgdb-bugreport@lists.sourceforge.net, LKML , Petr Mladek , Sumit Garg Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Mon, Jun 29, 2020 at 1:50 PM Cengiz Can wrote: > > `kdb_msg_write` operates on a global `struct kgdb_io *` called > `dbg_io_ops`. > > It's initialized in `debug_core.c` and checked throughout the debug > flow. > > There's a null check in `kdb_msg_write` which triggers static analyzers > and gives the (almost entirely wrong) impression that it can be null. > > Coverity scanner caught this as CID 1465042. > > I have removed the unnecessary null check and eliminated false-positive > forward null dereference warning. > > Signed-off-by: Cengiz Can > --- > kernel/debug/kdb/kdb_io.c | 12 +++++------- > 1 file changed, 5 insertions(+), 7 deletions(-) > > diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c > index 683a799618ad..4ac59a4fbeec 100644 > --- a/kernel/debug/kdb/kdb_io.c > +++ b/kernel/debug/kdb/kdb_io.c > @@ -549,14 +549,12 @@ static void kdb_msg_write(const char *msg, int msg_len) > if (msg_len == 0) > return; > > - if (dbg_io_ops) { > - const char *cp = msg; > - int len = msg_len; > + const char *cp = msg; > + int len = msg_len; kernel/debug/kdb/kdb_io.c:552:14: warning: ISO C90 forbids mixing declarations and code [-Wdeclaration-after-statement] -Doug