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Wysocki" , Len Brown , Mika Westerberg , Andy Shevchenko , Hans de Goede , Sakari Ailus , Rasmus Villemoes , Keith Busch , Heikki Krogerus , linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com Subject: Re: [PATCH] acpi: fix false-positive -Wuninitialized warning Message-ID: <20190712180024.GA21382@archlinux-threadripper> References: <20190712090148.36582-1-arnd@arndb.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190712090148.36582-1-arnd@arndb.de> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On Fri, Jul 12, 2019 at 11:01:21AM +0200, Arnd Bergmann wrote: > clang gets confused by an uninitialized variable in what looks > to it like a never executed code path: > > arch/x86/kernel/acpi/boot.c:618:13: error: variable 'polarity' is uninitialized when used here [-Werror,-Wuninitialized] > polarity = polarity ? ACPI_ACTIVE_LOW : ACPI_ACTIVE_HIGH; > ^~~~~~~~ > arch/x86/kernel/acpi/boot.c:606:32: note: initialize the variable 'polarity' to silence this warning > int rc, irq, trigger, polarity; > ^ > = 0 > arch/x86/kernel/acpi/boot.c:617:12: error: variable 'trigger' is uninitialized when used here [-Werror,-Wuninitialized] > trigger = trigger ? ACPI_LEVEL_SENSITIVE : ACPI_EDGE_SENSITIVE; > ^~~~~~~ > arch/x86/kernel/acpi/boot.c:606:22: note: initialize the variable 'trigger' to silence this warning > int rc, irq, trigger, polarity; > ^ > = 0 > > This is unfortunately a design decision in clang and won't be fixed. > > Changing the acpi_get_override_irq() macro to an inline function > reliably avoids the issue. > > Signed-off-by: Arnd Bergmann Reviewed-by: Nathan Chancellor