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d=linux-foundation.org; s=korg; t=1695172582; bh=ZJvJelQHpjIsZ4koDpubhMJD9fKMY42nHXLM3+Cc++k=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=t3wZndf2jFKdtKpqi6QxOV1db4+UoZX04LgBoPhwZ/XIvOo5qifR6InaHB/Gpu04W 92yUDmqD75UnCPnYcU0yw33jpOiKBhZfwCvZm67siwmdFWhpcghnoC8g30nHX6bD6D rn7Zh1oQNBwS3xw0OFZs6pTkdrMBEVb674kMwIWE= Date: Tue, 19 Sep 2023 18:16:21 -0700 From: Andrew Morton To: Baoquan He Cc: kernel test robot , oe-kbuild-all@lists.linux.dev, Linux Memory Management List , Zhen Lei Subject: Re: [linux-next:master 5741/5912] kernel/crash_core.c:214:13: warning: argument 2 null where non-null expected Message-Id: <20230919181621.382be43e97f51effb47ab412@linux-foundation.org> In-Reply-To: References: <202309191144.B0MToaPG-lkp@intel.com> <20230919094200.0f6495393a8eef3dc398e8ac@linux-foundation.org> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 51F87140003 X-Rspam-User: X-Rspamd-Server: rspam04 X-Stat-Signature: y4mesjm1fwf5r65tgsgprednkpxpnkde X-HE-Tag: 1695172584-379806 X-HE-Meta: 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 K8i9oD0Y hElFrADRzQ6pyIy9KB8BXGFNu2/CUIbLhf6XuQMORoSeOWc07RxlRFQE9DDwNTsqImepEvMeQTx3fufUbNvLLMedw2iTyxwOQSRmcoblcS52JPLfugsIYPtG4z91lNKUE14lfsaQOeb1U9vK1o5ZVIsWJCe9NrH0bi2/nOfWI/eocgYtmJLHhXx+Jm1k1jCbHmuXn8nw7yJB1BozW0NFhFCj8Y8i5zMN9MogFMVeRkA1TLcs/R492uH51flm+TJvaoMQbR/D3voOntlrXk4rsNO2Wp0pDxKcHKD/I+OGdFhPIuPIF3iZKJe/3lrhBajBxNgsDefpzTNKZ+mTt/9o/mTqvwH13wGpIkztZjD356ceHuU18Yi8KnJix1Zz/dz5/4Zh3AFXsziX5oqo= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, 20 Sep 2023 07:11:45 +0800 Baoquan He wrote: > > > > ret = __parse_crashkernel(cmdline, system_ram, crash_size, > > crash_base, NULL); > > > > and that suffix==NULL gets passed through to the strncmp()? > > Yeah, this looks like a false positive report. I reproduced this, below > change can mute the warning. However, the null pointer checking has been > done in __parse_crashkernel() when calls parse_crashkernel_suffix(). How the heck did I miss that. > Add below check anyway to satisfy the W=1 compiling? I dunno, gcc is so wrong here I'm inclined to leave it as-is, because surely this will get fixed in later gcc's. > --- a/kernel/crash_core.c > +++ b/kernel/crash_core.c > @@ -204,6 +204,9 @@ static int __init parse_crashkernel_suffix(char *cmdline, > { > char *cur = cmdline; > > + if(!suffix) > + return -EINVAL; > + > *crash_size = memparse(cmdline, &cur); > if (cmdline == cur) { > pr_warn("crashkernel: memory value expected\n"); If we were to do this, let's have a comment explaining why we're doing it - otherwise helpful people will try to remove it again.