From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH v4 8/9] netlink: fix nla_put_{u8,u16,u32} for KASAN Date: Mon, 25 Sep 2017 20:19:51 -0700 (PDT) Message-ID: <20170925.201951.1512252559012166718.davem@davemloft.net> References: <20170922212930.620249-1-arnd@arndb.de> <20170922212930.620249-9-arnd@arndb.de> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: mchehab@kernel.org, jiri@resnulli.us, arend.vanspriel@broadcom.com, kvalo@codeaurora.org, aryabinin@virtuozzo.com, glider@google.com, dvyukov@google.com, yamada.masahiro@socionext.com, mmarek@suse.com, akpm@linux-foundation.org, keescook@chromium.org, geert@linux-m68k.org, gregkh@linuxfoundation.org, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-wireless@vger.kernel.org, brcm80211-dev-list.pdl@broadcom.com, brcm80211-dev-list@cypress.com, kasan-dev@googlegroups.com, linux-kbuild@vger.kernel.org, jakub@gcc.gnu.org, marxin@gcc.gnu.org, stable@vger.kernel.org To: arnd@arndb.de Return-path: In-Reply-To: <20170922212930.620249-9-arnd@arndb.de> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org From: Arnd Bergmann Date: Fri, 22 Sep 2017 23:29:19 +0200 > When CONFIG_KASAN is enabled, the "--param asan-stack=1" causes rather large > stack frames in some functions. This goes unnoticed normally because > CONFIG_FRAME_WARN is disabled with CONFIG_KASAN by default as of commit > 3f181b4d8652 ("lib/Kconfig.debug: disable -Wframe-larger-than warnings with > KASAN=y"). > > The kernelci.org build bot however has the warning enabled and that led > me to investigate it a little further, as every build produces these warnings: > > net/wireless/nl80211.c:4389:1: warning: the frame size of 2240 bytes is larger than 2048 bytes [-Wframe-larger-than=] > net/wireless/nl80211.c:1895:1: warning: the frame size of 3776 bytes is larger than 2048 bytes [-Wframe-larger-than=] > net/wireless/nl80211.c:1410:1: warning: the frame size of 2208 bytes is larger than 2048 bytes [-Wframe-larger-than=] > net/bridge/br_netlink.c:1282:1: warning: the frame size of 2544 bytes is larger than 2048 bytes [-Wframe-larger-than=] > > Most of this problem is now solved in gcc-8, which can consolidate > the stack slots for the inline function arguments. On older compilers > we can add a workaround by declaring a local variable in each function > to pass the inline function argument. > > Cc: stable@vger.kernel.org > Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81715 > Signed-off-by: Arnd Bergmann Applied.