Re: [PATCH RFC v3 09/36] kmsan: add KMSAN bits to struct page and struct task_struct

[Marco Elver <elver@google.com>]

On Fri, 22 Nov 2019 at 12:26, <glider@google.com> wrote:
>
> Each struct page now contains pointers to two struct pages holding KMSAN
> metadata (shadow and origins) for the original struct page.
>
> Each task_struct contains a struct kmsan_task_state used to track the
> metadata of function parameters and return values for that task.
>
> Signed-off-by: Alexander Potapenko <glider@google.com>
> Cc: Jens Axboe <axboe@kernel.dk>
> Cc: Andy Lutomirski <luto@kernel.org>
> Cc: Vegard Nossum <vegard.nossum@oracle.com>
> Cc: Dmitry Vyukov <dvyukov@google.com>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: linux-mm@kvack.org
> ---
>
> Change-Id: Ie329527e558dd60307fb88b2da151f7f4db951ac
> ---
>  include/linux/mm_types.h | 9 +++++++++
>  include/linux/sched.h    | 5 +++++
>  2 files changed, 14 insertions(+)
>
> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
> index 2222fa795284..c87c5416a802 100644
> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -216,6 +216,15 @@ struct page {
>                                            not kmapped, ie. highmem) */
>  #endif /* WANT_PAGE_VIRTUAL */
>
> +#ifdef CONFIG_KMSAN
> +       /*
> +        * Bits in struct page are scarce, so the LSB in *shadow is used to
> +        * indicate whether the page should be ignored by KMSAN or not.
> +        */
> +       struct page *shadow;
> +       struct page *origin;
> +#endif
> +
>  #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
>         int _last_cpupid;
>  #endif
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index 72b20f33c56e..ba705f66f78c 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -15,6 +15,7 @@
>  #include <linux/sem.h>
>  #include <linux/shm.h>
>  #include <linux/kcov.h>
> +#include <linux/kmsan.h>

This file does not exist at this point in the series, and the build
would fail for all configs. This can cause problems for 'git bisect'
users etc.

I would just merge this patch with patch 10.

Thanks,
-- Marco


>  #include <linux/mutex.h>
>  #include <linux/plist.h>
>  #include <linux/hrtimer.h>
> @@ -1173,6 +1174,10 @@ struct task_struct {
>         unsigned int                    kasan_depth;
>  #endif
>
> +#ifdef CONFIG_KMSAN
> +       struct kmsan_task_state         kmsan;
> +#endif
> +
>  #ifdef CONFIG_FUNCTION_GRAPH_TRACER
>         /* Index of current stored address in ret_stack: */
>         int                             curr_ret_stack;
> --
> 2.24.0.432.g9d3f5f5b63-goog
>