Re: [PATCH mm 4/4] kasan: simplify kasan_complete_mode_report_info for tag-based modes

[Marco Elver <elver@google.com>]

On Thu, 21 Dec 2023 at 19:35, <andrey.konovalov@linux.dev> wrote:
>
> From: Andrey Konovalov <andreyknvl@google.com>
>
> memcpy the alloc/free tracks when collecting the information about a bad
> access instead of copying fields one by one.
>
> Fixes: 5d4c6ac94694 ("kasan: record and report more information")
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

Reviewed-by: Marco Elver <elver@google.com>

> ---
>  mm/kasan/report_tags.c | 23 ++++-------------------
>  1 file changed, 4 insertions(+), 19 deletions(-)
>
> diff --git a/mm/kasan/report_tags.c b/mm/kasan/report_tags.c
> index 688b9d70b04a..d15f8f580e2c 100644
> --- a/mm/kasan/report_tags.c
> +++ b/mm/kasan/report_tags.c
> @@ -27,15 +27,6 @@ static const char *get_common_bug_type(struct kasan_report_info *info)
>         return "invalid-access";
>  }
>
> -#ifdef CONFIG_KASAN_EXTRA_INFO
> -static void kasan_complete_extra_report_info(struct kasan_track *track,
> -                                        struct kasan_stack_ring_entry *entry)
> -{
> -       track->cpu = entry->track.cpu;
> -       track->timestamp = entry->track.timestamp;
> -}
> -#endif /* CONFIG_KASAN_EXTRA_INFO */
> -
>  void kasan_complete_mode_report_info(struct kasan_report_info *info)
>  {
>         unsigned long flags;
> @@ -80,11 +71,8 @@ void kasan_complete_mode_report_info(struct kasan_report_info *info)
>                         if (free_found)
>                                 break;
>
> -                       info->free_track.pid = entry->track.pid;
> -                       info->free_track.stack = entry->track.stack;
> -#ifdef CONFIG_KASAN_EXTRA_INFO
> -                       kasan_complete_extra_report_info(&info->free_track, entry);
> -#endif /* CONFIG_KASAN_EXTRA_INFO */
> +                       memcpy(&info->free_track, &entry->track,
> +                              sizeof(info->free_track));

Not sure why the line break is necessary.

>                         free_found = true;
>
>                         /*
> @@ -98,11 +86,8 @@ void kasan_complete_mode_report_info(struct kasan_report_info *info)
>                         if (alloc_found)
>                                 break;
>
> -                       info->alloc_track.pid = entry->track.pid;
> -                       info->alloc_track.stack = entry->track.stack;
> -#ifdef CONFIG_KASAN_EXTRA_INFO
> -                       kasan_complete_extra_report_info(&info->alloc_track, entry);
> -#endif /* CONFIG_KASAN_EXTRA_INFO */
> +                       memcpy(&info->alloc_track, &entry->track,
> +                              sizeof(info->alloc_track));
>                         alloc_found = true;
>
>                         /*
> --
> 2.25.1
>