Re: [PATCH] trace: skip hwasan

[Will Deacon]

On Sat, Feb 16, 2019 at 11:34:34PM -0500, Qian Cai wrote:
> Enabling function tracer with CONFIG_KASAN_SW_TAGS=y (hwasan) tracer
> causes the whole system frozen on ThunderX2 systems with 256 CPUs,
> because there is a burst of too much pointer access, and then KASAN will
> dereference each byte of the shadow address for the tag checking which
> will kill all the CPUs.
> 
> Signed-off-by: Qian Cai <cai@xxxxxx>
> ---
>  kernel/trace/Makefile | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
> index c2b2148bb1d2..fdd547a68385 100644
> --- a/kernel/trace/Makefile
> +++ b/kernel/trace/Makefile
> @@ -28,6 +28,11 @@ ifdef CONFIG_GCOV_PROFILE_FTRACE
>  GCOV_PROFILE := y
>  endif
>  
> +# Too much pointer access will kill hwasan.
> +ifdef CONFIG_KASAN_SW_TAGS
> +KASAN_SANITIZE := n
> +endif

I don't maintain this file, but I think that my comments on your related
patch are relevant here as well:

https://lkml.org/lkml/2019/2/18/223

Will