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[82.69.66.36]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-390cd8fbb5dsm3592424f8f.84.2025.02.25.14.49.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 25 Feb 2025 14:49:55 -0800 (PST) Date: Tue, 25 Feb 2025 22:49:54 +0000 From: David Laight To: Martin Uecker Cc: Steven Rostedt , Linus Torvalds , linux-kernel@vger.kernel.org, ksummit@lists.linux.dev Subject: Re: Rust kernel policy Message-ID: <20250225224954.4766e018@pumpkin> In-Reply-To: References: <326CC09B-8565-4443-ACC5-045092260677@zytor.com> <2025021954-flaccid-pucker-f7d9@gregkh> <4e316b01634642cf4fbb087ec8809d93c4b7822c.camel@tugraz.at> <2025022024-blooper-rippling-2667@gregkh> <1d43700546b82cf035e24d192e1f301c930432a3.camel@tugraz.at> <2025022042-jot-favored-e755@gregkh> <61a7e7db786d9549cbe201b153647689cbe12d75.camel@tugraz.at> <20250221124304.5dec31b2@gandalf.local.home> <6b3e4d3bdc9b6efd69068e5b22cfd05d370aed19.camel@tugraz.at> <20250221172415.5b632ae6@gandalf.local.home> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Sat, 22 Feb 2025 00:37:01 +0100 Martin Uecker wrote: > Am Freitag, dem 21.02.2025 um 17:24 -0500 schrieb Steven Rostedt: > > On Fri, 21 Feb 2025 11:30:41 -0800 > > Linus Torvalds wrote: > > > > > And yes, it's wrong in general. The problems with "x < 0" warning for > > > an unsigned 'x' are deep and fundamental, and macros that take various > > > types is only one (perhaps more obvious) example of how brokent that > > > garbage is. > > > > The bug I recently fixed, and I still constantly make, where this does > > help, is the difference between size_t vs ssize_t. I keep forgetting that > > size_t is unsigned, and I'll check a return of a function that returns > > negative on error with it. > > > > If I could just get a warning for this stupid mistake: > > > > size_t ret; > > > > ret = func(); > > if (ret < 0) > > error(); > > > > > > I'd be very happy. > > > > GCC has this warning, it is called -Wtype-limits That bleats about all sorts of stuff that is reasonable code. > > https://godbolt.org/z/M787vjhfo > > It is activated by -Wextra. > > (anyway, not at all related to my proposal) > > Martin > > > > > >