The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From dca5244d2f5b94f1809f0c02a549edf41ccd5493 Mon Sep 17 00:00:00 2001

From: Will Deacon will@kernel.org Date: Tue, 12 Jan 2021 22:48:32 +0000 Subject: [PATCH] compiler.h: Raise minimum version of GCC to 5.1 for arm64

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 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

diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index 74c6c0486eed..555ab0fddbef 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -13,6 +13,12 @@ /* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145 */ #if GCC_VERSION < 40900 # error Sorry, your version of GCC is too old - please use 4.9 or newer. +#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

/*