On Mon, Jan 18, 2021 at 5:54 AM Will Deacon <[email protected]> wrote: > > commit dca5244d2f5b94f1809f0c02a549edf41ccd5493 upstream. > > GCC versions >= 4.9 and < 5.1 have been shown to emit memory references > beyond the stack pointer, resulting in memory corruption if an interrupt > is taken after the stack pointer has been adjusted but before the > reference has been executed. This leads to subtle, infrequent data > corruption such as the EXT4 problems reported by Russell King at the > link below. > > Life is too short for buggy compilers, so raise the minimum GCC version > required by arm64 to 5.1. > > Reported-by: Russell King <[email protected]> > Suggested-by: Arnd Bergmann <[email protected]> > Signed-off-by: Will Deacon <[email protected]> > Tested-by: Nathan Chancellor <[email protected]> > Reviewed-by: Nick Desaulniers <[email protected]> > Reviewed-by: Nathan Chancellor <[email protected]> > Acked-by: Linus Torvalds <[email protected]> > Cc: <[email protected]> # 4.4.y, 4.9.y and 4.14.y only > Cc: Theodore Ts'o <[email protected]> > Cc: Florian Weimer <[email protected]> > Cc: Peter Zijlstra <[email protected]> > Cc: Nick Desaulniers <[email protected]> > Link: https://lore.kernel.org/r/[email protected] > Link: https://lore.kernel.org/r/[email protected] > Signed-off-by: Catalin Marinas <[email protected]> > [will: backport to 4.4.y/4.9.y/4.14.y]
Merging this from stable into "Android Common Kernel" trees that were built with AOSP GCC 4.9, I expect this to break some builds. Arnd, IIRC did you mention that AOSP GCC had picked up a fix? If so, did you verify that via disassembly, or gerrit patch file? (AOSP GCC 4.9: https://android.googlesource.com/platform/prebuilts/gcc/linux-x86/aarch64/aarch64-linux-android-4.9/ master branch, roll back a few commits). It looks like AOSP GCC `#defines __android__ 1`. I'm not arguing against a backport, just trying to think through how we'll need to sort this out downstream. (Revert or patch on top that checks for __android__, if AOSP GCC does in fact have a fix.) > Signed-off-by: Will Deacon <[email protected]> > --- > include/linux/compiler-gcc.h | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h > index af8b4a879934..3cc8adede67b 100644 > --- a/include/linux/compiler-gcc.h > +++ b/include/linux/compiler-gcc.h > @@ -145,6 +145,12 @@ > > #if GCC_VERSION < 30200 > # error Sorry, your compiler is too old - please upgrade it. > +#elif defined(CONFIG_ARM64) && GCC_VERSION < 50100 > +/* > + * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63293 > + * https://lore.kernel.org/r/[email protected] > + */ > +# error Sorry, your version of GCC is too old - please use 5.1 or newer. > #endif > > #if GCC_VERSION < 30300 > -- > 2.30.0.284.gd98b1dd5eaa7-goog > -- Thanks, ~Nick Desaulniers
