On Tue, Jan 19, 2021 at 02:15:43PM -0800, Nick Desaulniers wrote:
On Mon, Jan 18, 2021 at 5:54 AM Will Deacon will@kernel.org 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 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 # 4.4.y, 4.9.y and 4.14.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 4.4.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/aa... master branch, roll back a few commits). It looks like AOSP GCC `#defines __android__ 1`.
It seems like this is the source for that toolchain?
https://android.googlesource.com/toolchain/gcc
If so, it looks like that patch was picked up in this commit.
https://android.googlesource.com/toolchain/gcc/+/5ae0308a147ec3f6502fd321860...
Cheers, Nathan