On 2/22/19 5:29 PM, Arnd Bergmann wrote: > Building an arm64 allmodconfig kernel with clang results in over 140 warnings > about overly large stack frames, the worst ones being: > > drivers/gpu/drm/panel/panel-sitronix-st7789v.c:196:12: error: stack frame size of 20224 bytes in function 'st7789v_prepare' > drivers/video/fbdev/omap2/omapfb/displays/panel-tpo-td028ttec1.c:196:12: error: stack frame size of 13120 bytes in function 'td028ttec1_panel_enable' > drivers/usb/host/max3421-hcd.c:1395:1: error: stack frame size of 10048 bytes in function 'max3421_spi_thread' > drivers/net/wan/slic_ds26522.c:209:12: error: stack frame size of 9664 bytes in function 'slic_ds26522_probe' > drivers/crypto/ccp/ccp-ops.c:2434:5: error: stack frame size of 8832 bytes in function 'ccp_run_cmd' > drivers/media/dvb-frontends/stv0367.c:1005:12: error: stack frame size of 7840 bytes in function 'stv0367ter_algo' > > None of these happen with gcc today, and almost all of these are the result > of a single known issue in llvm. Hopefully it will eventually get fixed with > the clang-9 release. > > In the meantime, the best idea I have is to turn off asan-stack for clang-8 > and earlier, so we can produce a kernel that is safe to run. > > I have posted three patches that address the frame overflow warnings that are > not addressed by turning off asan-stack, so in combination with this change, > we get much closer to a clean allmodconfig build, which in turn is necessary > to do meaningful build regression testing. > > It is still possible to turn on the CONFIG_ASAN_STACK option on all versions > of clang, and it's always enabled for gcc, but when CONFIG_COMPILE_TEST is > set, the option remains invisible, so allmodconfig and randconfig builds > (which are normally done with a forced CONFIG_COMPILE_TEST) will still result > in a mostly clean build. > > Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> > Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> > Cc: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> > Cc: Mark Brown <broonie@xxxxxxxxxx> > Cc: Qian Cai <cai@xxxxxx> > Cc: Kostya Serebryany <kcc@xxxxxxxxxx> > Cc: Andrey Konovalov <andreyknvl@xxxxxxxxxx> > Link: https://bugs.llvm.org/show_bug.cgi?id=38809 > Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> > --- Reviewed-by: Qian Cai <cai@xxxxxx>
