On 12/13/2018 10:53 AM, Rong Chen wrote:

On 12/09/2018 06:37 PM, Russell King - ARM Linux wrote:

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?

Hi,

I'm sorry for the trouble, It's a false warning, we will look into it.

Best Regards,
Rong Chen

Hi all,

I tested the commit on another machine and the warnings are exist.
I found " -Wno-vla" was lost after the commit, so I think it's a real problem.

-Werror=designated-init -fplugin-arg-arm_ssp_per_task_plugin-tso=1 -fplugin-arg-arm_ssp_per_task_plugin-offset=24 -fsanitize=shift -fsanitize=integer-divide-by-zero -fsanitize=unreachable -fsanitize=vla-bound -fsanitize=signed-integer-overflow -fsanitize=bounds -fsanitize=object-size -fsanitize=bool -fsanitize=enum -fsanitize=alignment -Wno-maybe-uninitialized -fsanitize-coverage=trace-pc -DMODULE -DKBUILD_BASENAME='"test_ubsan"' -DKBUILD_MODNAME='"test_ubsan"' -c -o lib/.tmp_test_ubsan.o lib/test_ubsan.c

-Werror=designated-init -Wno-vla -fsanitize=shift -fsanitize=integer-divide-by-zero -fsanitize=unreachable -fsanitize=vla-bound -fsanitize=signed-integer-overflow -fsanitize=bounds -fsanitize=object-size -fsanitize=bool -fsanitize=enum -fsanitize=alignment -Wno-maybe-uninitialized -fsanitize-coverage=trace-pc -DMODULE -DKBUILD_BASENAME='"test_ubsan"' -DKBUILD_MODNAME='"test_ubsan"' -c -o lib/.tmp_test_ubsan.o lib/test_ubsan.c

Best Regards,
Rong Chen

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 <jinb.park7@gmail.com>
:::::: CC: Linus Torvalds <torvalds@linux-foundation.org>

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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