From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sun, 9 Dec 2018 10:37:40 +0000 From: Russell King - ARM Linux Subject: Re: [PATCH v3] ARM: smp: add support for per-task stack canaries Message-ID: <20181209103740.GB30658@n2100.armlinux.org.uk> References: <20181206083257.9596-1-ard.biesheuvel@linaro.org> <201812091807.4emRkZ7L%fengguang.wu@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201812091807.4emRkZ7L%fengguang.wu@intel.com> Sender: Russell King - ARM Linux To: kbuild test robot Cc: Ard Biesheuvel , kbuild-all@01.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Kees Cook , Emese Revfy , Arnd Bergmann , Laura Abbott , kernel-hardening@lists.openwall.com List-ID: On Sun, Dec 09, 2018 at 06:28:11PM +0800, kbuild test robot wrote: > Hi Ard, > > I love your patch! Perhaps something to improve: Hi, This looks to me like a false warning - how can a patch touching arch code affect the result of lib/test_ubsan.c? Please can you double- check this result? Thanks. > > [auto build test WARNING on arm/for-next] > [also build test WARNING on v4.20-rc5] > [if your patch is applied to the wrong git tree, please drop us a note to help improve the system] > > url: https://github.com/0day-ci/linux/commits/Ard-Biesheuvel/ARM-smp-add-support-for-per-task-stack-canaries/20181209-033321 > base: git://git.armlinux.org.uk/~rmk/linux-arm.git for-next > config: arm-allmodconfig (attached as .config) > compiler: arm-linux-gnueabi-gcc (Debian 7.2.0-11) 7.2.0 > reproduce: > wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross > chmod +x ~/bin/make.cross > # save the attached .config to linux build tree > GCC_VERSION=7.2.0 make.cross ARCH=arm > > All warnings (new ones prefixed by >>): > > lib/test_ubsan.c: In function 'test_ubsan_vla_bound_not_positive': > >> lib/test_ubsan.c:48:2: warning: ISO C90 forbids variable length array 'buf' [-Wvla] > char buf[size]; > ^~~~ > lib/test_ubsan.c: In function 'test_ubsan_out_of_bounds': > >> lib/test_ubsan.c:64:2: warning: ISO C90 forbids variable length array 'arr' [-Wvla] > volatile int arr[i]; > ^~~~~~~~ > > vim +/buf +48 lib/test_ubsan.c > > 854686f4 Jinbum Park 2018-04-10 44 > 854686f4 Jinbum Park 2018-04-10 45 static void test_ubsan_vla_bound_not_positive(void) > 854686f4 Jinbum Park 2018-04-10 46 { > 854686f4 Jinbum Park 2018-04-10 47 volatile int size = -1; > 854686f4 Jinbum Park 2018-04-10 @48 char buf[size]; > 854686f4 Jinbum Park 2018-04-10 49 > 854686f4 Jinbum Park 2018-04-10 50 (void)buf; > 854686f4 Jinbum Park 2018-04-10 51 } > 854686f4 Jinbum Park 2018-04-10 52 > 854686f4 Jinbum Park 2018-04-10 53 static void test_ubsan_shift_out_of_bounds(void) > 854686f4 Jinbum Park 2018-04-10 54 { > 854686f4 Jinbum Park 2018-04-10 55 volatile int val = -1; > 854686f4 Jinbum Park 2018-04-10 56 int val2 = 10; > 854686f4 Jinbum Park 2018-04-10 57 > 854686f4 Jinbum Park 2018-04-10 58 val2 <<= val; > 854686f4 Jinbum Park 2018-04-10 59 } > 854686f4 Jinbum Park 2018-04-10 60 > 854686f4 Jinbum Park 2018-04-10 61 static void test_ubsan_out_of_bounds(void) > 854686f4 Jinbum Park 2018-04-10 62 { > 854686f4 Jinbum Park 2018-04-10 63 volatile int i = 4, j = 5; > 854686f4 Jinbum Park 2018-04-10 @64 volatile int arr[i]; > 854686f4 Jinbum Park 2018-04-10 65 > 854686f4 Jinbum Park 2018-04-10 66 arr[j] = i; > 854686f4 Jinbum Park 2018-04-10 67 } > 854686f4 Jinbum Park 2018-04-10 68 > > :::::: The code at line 48 was first introduced by commit > :::::: 854686f4edf483db1e0d26d972bdb8fb65c8bfaa lib: add testing module for UBSAN > > :::::: TO: Jinbum Park > :::::: CC: Linus Torvalds > > --- > 0-DAY kernel test infrastructure Open Source Technology Center > https://lists.01.org/pipermail/kbuild-all Intel Corporation -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up According to speedtest.net: 11.9Mbps down 500kbps up