On Mon, May 06, 2019 at 06:36:45PM +0300, Andrey Ryabinin wrote: > > > On 5/6/19 6:10 PM, Greg Kroah-Hartman wrote: > > On Mon, May 06, 2019 at 05:55:54PM +0300, Andrey Ryabinin wrote: > >> > >> > >> On 5/6/19 5:32 PM, Greg Kroah-Hartman wrote: > >>> From: Andrey Ryabinin <[email protected]> > >>> > >>> commit c5caf21ab0cf884ef15b25af234f620e4a233139 upstream. > >>> > >>> In the upcoming gcc7 release, the -fsanitize=kernel-address option at > >>> first implied new -fsanitize-address-use-after-scope option. This would > >>> cause link errors on older kernels because they don't have two new > >>> functions required for use-after-scope support. Therefore, gcc7 changed > >>> default to -fno-sanitize-address-use-after-scope. > >>> > >>> Now the kernel has everything required for that feature since commit > >>> 828347f8f9a5 ("kasan: support use-after-scope detection"). So, to make it > >>> work, we just have to enable use-after-scope in CFLAGS. > >>> > >>> Link: > >>> http://lkml.kernel.org/r/[email protected] > >>> Signed-off-by: Andrey Ryabinin <[email protected]> > >>> Acked-by: Dmitry Vyukov <[email protected]> > >>> Cc: Alexander Potapenko <[email protected]> > >>> Cc: Andrey Konovalov <[email protected]> > >>> Signed-off-by: Andrew Morton <[email protected]> > >>> Signed-off-by: Linus Torvalds <[email protected]> > >>> Signed-off-by: Andrey Konovalov <[email protected]> > >>> Signed-off-by: Greg Kroah-Hartman <[email protected]> > >>> > >>> --- > >>> scripts/Makefile.kasan | 2 ++ > >>> 1 file changed, 2 insertions(+) > >>> > >>> --- a/scripts/Makefile.kasan > >>> +++ b/scripts/Makefile.kasan > >>> @@ -29,6 +29,8 @@ else > >>> endif > >>> endif > >>> > >>> +CFLAGS_KASAN += $(call cc-option, -fsanitize-address-use-after-scope) > >>> + > >>> CFLAGS_KASAN_NOSANITIZE := -fno-builtin > >>> > >>> endif > >>> > >>> > >> > >> This shouldn't be in the -stable. > > > > Why not? Does no one use gcc7 with this kernel and kasan? > > > > You don't need this patch to use kasan on this kernel with gcc7. > This patch only enables detection of use-after-scope bugs. This feature > appeared to be useless, > hence it disabled recently by commit 7771bdbbfd3d ("kasan: remove use after > scope bugs detection.")
Ah, didn't notice that, nice! Ok, I'll go drop this, thanks for letting me know. > The link errors mentioned in changelog was the problem only for some period > of time in the development branch of GCC 7. > The released GCC7 version doesn't have this problem. Also good to know, thanks! greg k-h
