On Thu, Oct 29, 2020 at 11:05 AM 'Fangrui Song' via Clang Built Linux
<clang-built-linux@xxxxxxxxxxxxxxxx> wrote:
>
> Commit 393f203f5fd5 ("x86_64: kasan: add interceptors for
> memset/memmove/memcpy functions") added .weak directives to
> arch/x86/lib/mem*_64.S instead of changing the existing SYM_FUNC_START_*
> macros. This can lead to the assembly snippet `.weak memcpy ... .globl
> memcpy` which will produce a STB_WEAK memcpy with GNU as but STB_GLOBAL
> memcpy with LLVM's integrated assembler before LLVM 12. LLVM 12 (since
> https://reviews.llvm.org/D90108) will error on such an overridden symbol
> binding.
>
> Use the appropriate SYM_FUNC_START_WEAK instead.
>
> Fixes: 393f203f5fd5 ("x86_64: kasan: add interceptors for memset/memmove/memcpy functions")
> Reported-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx>
> Signed-off-by: Fangrui Song <maskray@xxxxxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx>
> ---
> arch/x86/lib/memcpy_64.S | 4 +---
> arch/x86/lib/memmove_64.S | 4 +---
> arch/x86/lib/memset_64.S | 4 +---
> 3 files changed, 3 insertions(+), 9 deletions(-)
Thank you for fixing this! I tested the patch with gcc 9.3 and clang
12, both with and without Clang's integrated assembler, and the kernel
builds and boots with all compilers again.
Tested-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx>
Sami
