Hi Yanjun, On Fri, Jan 19, 2024 at 03:44:35PM +0800, Zhu Yanjun wrote: > > 在 2024/1/19 4:36, kernel test robot 写道: > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master > > head: 2863b714f3ad0a9686f2de1b779228ad8c7a8052 > > commit: e3fe8d28c67bf6c291e920c6d04fa22afa14e6e4 [13015/13783] virtio_net: Fix "‘%d’ directive writing between 1 and 11 bytes into a region of size 10" warnings > > config: x86_64-sof-customedconfig-avs-defconfig (https://download.01.org/0day-ci/archive/20240119/202401190425.IGYMqCJW-lkp@xxxxxxxxx/config) > > compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0 > > I can reproduce this problem in my local host. > > It seems that this problem is related with gcc-7. In the same test > environment, with gcc-7, this problem will occur. With gcc later than > version 9, this problem will not occur. > > And with u16, the range of %u should be [0, 65535]. Not the following: > " > drivers/net/virtio_net.c:4141:27: note: directive argument in the range > [0, 2147483647] > sprintf(vi->sq[i].name, "output.%u", i); " > > And the size of name is 16. That is, the name string can contain 15 bytes > characters. > When the variable i is set to the maximum 65535, the string should be > "output.65535". The size of the string is 12 + 1 = 13 bytes. > The size of the name is greater than the maximum string "output.65535". > > In short, from the above, this problem results from gcc-7. It is a problem > with gcc-7. Based on my tests with gcc-9, gcc-13, this problem is fixed in > later gcc versions. > And the warning is a false warning to this commit. Thanks for the detailed analysis. We will configure the bot to ignore this specific "format-overflow" error under gcc-7 to avoid more false reports. Best Regards, Yujie > > Best Regards > Zhu Yanjun > > > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240119/202401190425.IGYMqCJW-lkp@xxxxxxxxx/reproduce) > > > > If you fix the issue in a separate patch/commit (i.e. not just a new version of > > the same patch/commit), kindly add following tags > > | Reported-by: kernel test robot <lkp@xxxxxxxxx> > > | Closes: https://lore.kernel.org/oe-kbuild-all/202401190425.IGYMqCJW-lkp@xxxxxxxxx/ > > > > All errors (new ones prefixed by >>): > > > > drivers/net/virtio_net.c: In function 'init_vqs': > > drivers/net/virtio_net.c:4339:36: error: 'sprintf' may write a terminating nul past the end of the destination [-Werror=format-overflow=] > > sprintf(vi->rq[i].name, "input.%u", i); > > ^ > > drivers/net/virtio_net.c:4339:3: note: 'sprintf' output between 8 and 17 bytes into a destination of size 16 > > sprintf(vi->rq[i].name, "input.%u", i); > > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > > drivers/net/virtio_net.c:4340:35: error: '%u' directive writing between 1 and 10 bytes into a region of size 9 [-Werror=format-overflow=] > > sprintf(vi->sq[i].name, "output.%u", i); > > ^~ > > drivers/net/virtio_net.c:4340:27: note: directive argument in the range [0, 2147483647] > > sprintf(vi->sq[i].name, "output.%u", i); > > ^~~~~~~~~~~ > > drivers/net/virtio_net.c:4340:3: note: 'sprintf' output between 9 and 18 bytes into a destination of size 16 > > sprintf(vi->sq[i].name, "output.%u", i); > > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > cc1: all warnings being treated as errors >
