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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id x18sm2934984pfr.106.2020.06.03.19.44.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 03 Jun 2020 19:44:54 -0700 (PDT) Date: Wed, 3 Jun 2020 19:44:53 -0700 From: Kees Cook To: Joe Perches Cc: linux-kernel@vger.kernel.org, Linus Torvalds , Miguel Ojeda , Alexander Potapenko , Andy Whitcroft , x86@kernel.org, drbd-dev@lists.linbit.com, linux-block@vger.kernel.org, b43-dev@lists.infradead.org, netdev@vger.kernel.org, linux-wireless@vger.kernel.org, linux-ide@vger.kernel.org, linux-clk@vger.kernel.org, linux-spi@vger.kernel.org, linux-mm@kvack.org, clang-built-linux@googlegroups.com Subject: Re: [PATCH 08/10] checkpatch: Remove awareness of uninitialized_var() macro Message-ID: <202006031944.9551FAA68E@keescook> References: <20200603233203.1695403-1-keescook@chromium.org> <20200603233203.1695403-9-keescook@chromium.org> <202006031838.55722640DC@keescook> <6f921002478544217903ee4bfbe3c400e169687f.camel@perches.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6f921002478544217903ee4bfbe3c400e169687f.camel@perches.com> X-Rspamd-Queue-Id: 28ADC180D0180 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 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, Jun 03, 2020 at 06:47:13PM -0700, Joe Perches wrote: > On Wed, 2020-06-03 at 18:40 -0700, Kees Cook wrote: > > On Wed, Jun 03, 2020 at 05:02:29PM -0700, Joe Perches wrote: > > > On Wed, 2020-06-03 at 16:32 -0700, Kees Cook wrote: > > > > Using uninitialized_var() is dangerous as it papers over real bugs[1] > > > > (or can in the future), and suppresses unrelated compiler warnings > > > > (e.g. "unused variable"). If the compiler thinks it is uninitialized, > > > > either simply initialize the variable or make compiler changes. > > > > > > > > In preparation for removing[2] the[3] macro[4], effectively revert > > > > commit 16b7f3c89907 ("checkpatch: avoid warning about uninitialized_var()") > > > > and remove all remaining mentions of uninitialized_var(). > > > > > > > > [1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/ > > > > [2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/ > > > > [3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/ > > > > [4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/ > > > > > > nack. see below. > > > > > > I'd prefer a simple revert, but it shouldn't > > > be done here. > > > > What do you mean? (I can't understand this and "fine by me" below?) > > I did write "other than that"... > > I mean that the original commit fixed 2 issues, > one with the uninitialized_var addition, and > another with the missing void function declaration. > > I think I found the missing void function bit because > the uninitialized_var use looked like a function so I > fixed both things at the same time. > > If you change it, please just remove the bit that > checks for uninitialized_var. Ah! Gotcha. Thanks; I will update it. -Kees > > Thanks, Joe > > > > > diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl > > > [] > > > > @@ -4075,7 +4074,7 @@ sub process { > > > > } > > > > > > > > # check for function declarations without arguments like "int foo()" > > > > - if ($line =~ /(\b$Type\s*$Ident)\s*\(\s*\)/) { > > > > + if ($line =~ /(\b$Type\s+$Ident)\s*\(\s*\)/) { > > > > > > This isn't right because $Type includes a possible trailing * > > > where there isn't a space between $Type and $Ident > > > > Ah, hm, that was changed in the mentioned commit: > > > > - if ($line =~ /(\b$Type\s+$Ident)\s*\(\s*\)/) { > > + if ($line =~ /(\b$Type\s*$Ident)\s*\(\s*\)/) { > > > > > e.g.: int *bar(void); > > > > > > Other than that, fine by me... > > > > Thanks for looking it over! I'll adjust it however you'd like. :) > > > -- Kees Cook