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 linux@armlinux.org.uk Suggested-by: Arnd Bergmann arnd@kernel.org Signed-off-by: Will Deacon will@kernel.org Tested-by: Nathan Chancellor natechancellor@gmail.com Reviewed-by: Nick Desaulniers ndesaulniers@google.com Reviewed-by: Nathan Chancellor natechancellor@gmail.com Acked-by: Linus Torvalds torvalds@linux-foundation.org Cc: stable@vger.kernel.org # 4.19.y and 5.4.y only Cc: Theodore Ts'o tytso@mit.edu Cc: Florian Weimer fweimer@redhat.com Cc: Peter Zijlstra peterz@infradead.org Cc: Nick Desaulniers ndesaulniers@google.com Link: https://lore.kernel.org/r/20210105154726.GD1551@shell.armlinux.org.uk Link: https://lore.kernel.org/r/20210112224832.10980-1-will@kernel.org Signed-off-by: Catalin Marinas catalin.marinas@arm.com [will: backport to 4.19.y/5.4.y] Signed-off-by: Will Deacon will@kernel.org --- 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 14be09537109..a80d6de3c8ad 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -12,6 +12,12 @@

#if GCC_VERSION < 40600 # 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/20210107111841.GN1551@shell.armlinux.org.uk + */ +# error Sorry, your version of GCC is too old - please use 5.1 or newer. #endif

/*