On Mon, Sep 28, 2020 at 12:03 AM 'Marco Elver' via Clang Built Linux <clang-built-linux@xxxxxxxxxxxxxxxx> wrote: > > On Sun, 27 Sep 2020 at 22:14, kernel test robot <lkp@xxxxxxxxx> wrote: > > > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master > > head: 20dc779fdefc40bf7dd9736cea01704f29228fae > > commit: 2ce416ba162877d5cf267ac35548ea45eba84150 [11080/11173] ubsan: introduce CONFIG_UBSAN_LOCAL_BOUNDS for Clang > > config: powerpc-randconfig-r004-20200927 (attached as .config) ^ randconfig > > compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 6d374cf78c8a80a0bbfc7ce9bc80b3f183f44c80) > > reproduce (this is a W=1 build): > > wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross > > chmod +x ~/bin/make.cross > > # install powerpc cross compiling tool for clang build > > # apt-get install binutils-powerpc-linux-gnu > > # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=2ce416ba162877d5cf267ac35548ea45eba84150 > > git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git > > git fetch --no-tags linux-next master > > git checkout 2ce416ba162877d5cf267ac35548ea45eba84150 > > # save the attached .config to linux build tree > > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc > > > > If you fix the issue, kindly add following tag as appropriate > > Reported-by: kernel test robot <lkp@xxxxxxxxx> > > > > All warnings (new ones prefixed by >>): > > > > >> drivers/media/common/saa7146/saa7146_hlp.c:648:5: warning: stack frame size of 1072 bytes in function 'saa7146_enable_overlay' [-Wframe-larger-than=] > > int saa7146_enable_overlay(struct saa7146_fh *fh) > > ^ > > 1 warning generated. > > This warning must have existed before, because the UBSAN patch didn't > add any features, it just guarded them with extra Kconfig options. Likely. > > Also, this is with Clang 12, which is very much in development and > quite unstable. I wrote a tool that can help debug these: https://github.com/ClangBuiltLinux/frame-larger-than The compiler is quite unhelpful in the warning; but recompiling with debug info gives you info about stack slots and the size of those types. This is a randconfig, so always weird things get pulled in. Sometimes these are large stack allocations that should be heap allocated; sometimes it's KASAN enabled via randconfig. I noticed that KASAN+clang has pretty poor stack slot reuse, which triggers these often: https://github.com/ClangBuiltLinux/linux/issues/39 I didn't check this config to see if KASAN was set or not, but I wouldn't chalk it up to "clang 12 being unstable." > > > vim +/saa7146_enable_overlay +648 drivers/media/common/saa7146/saa7146_hlp.c > > > > ^1da177e4c3f41 drivers/media/common/saa7146_hlp.c Linus Torvalds 2005-04-16 647 > > ^1da177e4c3f41 drivers/media/common/saa7146_hlp.c Linus Torvalds 2005-04-16 @648 int saa7146_enable_overlay(struct saa7146_fh *fh) > > ^1da177e4c3f41 drivers/media/common/saa7146_hlp.c Linus Torvalds 2005-04-16 649 { > > ^1da177e4c3f41 drivers/media/common/saa7146_hlp.c Linus Torvalds 2005-04-16 650 struct saa7146_dev *dev = fh->dev; > > ^1da177e4c3f41 drivers/media/common/saa7146_hlp.c Linus Torvalds 2005-04-16 651 struct saa7146_vv *vv = dev->vv_data; > > ^1da177e4c3f41 drivers/media/common/saa7146_hlp.c Linus Torvalds 2005-04-16 652 > > 5da545ad08a3c6 drivers/media/common/saa7146_hlp.c Hans Verkuil 2012-05-01 653 saa7146_set_window(dev, vv->ov.win.w.width, vv->ov.win.w.height, vv->ov.win.field); > > 5da545ad08a3c6 drivers/media/common/saa7146_hlp.c Hans Verkuil 2012-05-01 654 saa7146_set_position(dev, vv->ov.win.w.left, vv->ov.win.w.top, vv->ov.win.w.height, vv->ov.win.field, vv->ov_fmt->pixelformat); > > ^1da177e4c3f41 drivers/media/common/saa7146_hlp.c Linus Torvalds 2005-04-16 655 saa7146_set_output_format(dev, vv->ov_fmt->trans); > > ^1da177e4c3f41 drivers/media/common/saa7146_hlp.c Linus Torvalds 2005-04-16 656 saa7146_set_clipping_rect(fh); > > ^1da177e4c3f41 drivers/media/common/saa7146_hlp.c Linus Torvalds 2005-04-16 657 > > ^1da177e4c3f41 drivers/media/common/saa7146_hlp.c Linus Torvalds 2005-04-16 658 /* enable video dma1 */ > > ^1da177e4c3f41 drivers/media/common/saa7146_hlp.c Linus Torvalds 2005-04-16 659 saa7146_write(dev, MC1, (MASK_06 | MASK_22)); > > ^1da177e4c3f41 drivers/media/common/saa7146_hlp.c Linus Torvalds 2005-04-16 660 return 0; > > ^1da177e4c3f41 drivers/media/common/saa7146_hlp.c Linus Torvalds 2005-04-16 661 } > > ^1da177e4c3f41 drivers/media/common/saa7146_hlp.c Linus Torvalds 2005-04-16 662 > > > > :::::: The code at line 648 was first introduced by commit > > :::::: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Linux-2.6.12-rc2 > > > > :::::: TO: Linus Torvalds <torvalds@xxxxxxxxxxxxxxx> > > :::::: CC: Linus Torvalds <torvalds@xxxxxxxxxxxxxxx> > > > > --- > > 0-DAY CI Kernel Test Service, Intel Corporation > > https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx > > -- > You received this message because you are subscribed to the Google Groups "Clang Built Linux" group. > To unsubscribe from this group and stop receiving emails from it, send an email to clang-built-linux+unsubscribe@xxxxxxxxxxxxxxxx. > To view this discussion on the web visit https://groups.google.com/d/msgid/clang-built-linux/CANpmjNNcRCipPdd0C0z-dxb1nfz35bkgAY6eJwGF8sYq%3D2wOqQ%40mail.gmail.com. -- Thanks, ~Nick Desaulniers
