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References: <20231221183540.168428-1-andrey.konovalov@linux.dev> <20231221183540.168428-2-andrey.konovalov@linux.dev>
In-Reply-To: <20231221183540.168428-2-andrey.konovalov@linux.dev>
From: Marco Elver <elver@google.com>
Date: Thu, 21 Dec 2023 21:10:49 +0100
Message-ID: <CANpmjNPGBMD6XsPpdL-ix8VTuWAwV-jmBjLpC66Z5y543j0DuA@mail.gmail.com>
Subject: Re: [PATCH mm 2/4] kasan: reuse kasan_track in kasan_stack_ring_entry
To: andrey.konovalov@linux.dev
Cc: Andrew Morton <akpm@linux-foundation.org>, Juntong Deng <juntong.deng@outlook.com>, 
	Andrey Konovalov <andreyknvl@gmail.com>, Alexander Potapenko <glider@google.com>, 
	Dmitry Vyukov <dvyukov@google.com>, Andrey Ryabinin <ryabinin.a.a@gmail.com>, kasan-dev@googlegroups.com, 
	linux-mm@kvack.org, linux-kernel@vger.kernel.org, 
	Andrey Konovalov <andreyknvl@google.com>
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On Thu, 21 Dec 2023 at 19:35, <andrey.konovalov@linux.dev> wrote:
>
> From: Andrey Konovalov <andreyknvl@google.com>
>
> Avoid duplicating fields of kasan_track in kasan_stack_ring_entry:
> reuse the structure.

No functional change?

> 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/kasan.h       |  7 +------
>  mm/kasan/report_tags.c | 12 ++++++------
>  mm/kasan/tags.c        | 12 ++++++------
>  3 files changed, 13 insertions(+), 18 deletions(-)
>
> diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
> index 5e298e3ac909..9072ce4c1263 100644
> --- a/mm/kasan/kasan.h
> +++ b/mm/kasan/kasan.h
> @@ -279,13 +279,8 @@ struct kasan_free_meta {
>  struct kasan_stack_ring_entry {
>         void *ptr;
>         size_t size;
> -       u32 pid;
> -       depot_stack_handle_t stack;
> +       struct kasan_track track;
>         bool is_free;
> -#ifdef CONFIG_KASAN_EXTRA_INFO
> -       u64 cpu:20;
> -       u64 timestamp:44;
> -#endif /* CONFIG_KASAN_EXTRA_INFO */
>  };
>
>  struct kasan_stack_ring {
> diff --git a/mm/kasan/report_tags.c b/mm/kasan/report_tags.c
> index 979f284c2497..688b9d70b04a 100644
> --- a/mm/kasan/report_tags.c
> +++ b/mm/kasan/report_tags.c
> @@ -31,8 +31,8 @@ static const char *get_common_bug_type(struct kasan_report_info *info)
>  static void kasan_complete_extra_report_info(struct kasan_track *track,
>                                          struct kasan_stack_ring_entry *entry)
>  {
> -       track->cpu = entry->cpu;
> -       track->timestamp = entry->timestamp;
> +       track->cpu = entry->track.cpu;
> +       track->timestamp = entry->track.timestamp;
>  }
>  #endif /* CONFIG_KASAN_EXTRA_INFO */
>
> @@ -80,8 +80,8 @@ void kasan_complete_mode_report_info(struct kasan_report_info *info)
>                         if (free_found)
>                                 break;
>
> -                       info->free_track.pid = entry->pid;
> -                       info->free_track.stack = entry->stack;
> +                       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 */
> @@ -98,8 +98,8 @@ void kasan_complete_mode_report_info(struct kasan_report_info *info)
>                         if (alloc_found)
>                                 break;
>
> -                       info->alloc_track.pid = entry->pid;
> -                       info->alloc_track.stack = entry->stack;
> +                       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 */
> diff --git a/mm/kasan/tags.c b/mm/kasan/tags.c
> index c13b198b8302..c4d14dbf27c0 100644
> --- a/mm/kasan/tags.c
> +++ b/mm/kasan/tags.c
> @@ -100,8 +100,8 @@ static void save_extra_info(struct kasan_stack_ring_entry *entry)
>         u32 cpu = raw_smp_processor_id();
>         u64 ts_nsec = local_clock();
>
> -       entry->cpu = cpu;
> -       entry->timestamp = ts_nsec >> 3;
> +       entry->track.cpu = cpu;
> +       entry->track.timestamp = ts_nsec >> 3;
>  }
>  #endif /* CONFIG_KASAN_EXTRA_INFO */
>
> @@ -134,15 +134,15 @@ static void save_stack_info(struct kmem_cache *cache, void *object,
>         if (!try_cmpxchg(&entry->ptr, &old_ptr, STACK_RING_BUSY_PTR))
>                 goto next; /* Busy slot. */
>
> -       old_stack = entry->stack;
> +       old_stack = entry->track.stack;
>
>         entry->size = cache->object_size;
> -       entry->pid = current->pid;
> -       entry->stack = stack;
> -       entry->is_free = is_free;
> +       entry->track.pid = current->pid;
> +       entry->track.stack = stack;
>  #ifdef CONFIG_KASAN_EXTRA_INFO
>         save_extra_info(entry);
>  #endif /* CONFIG_KASAN_EXTRA_INFO */
> +       entry->is_free = is_free;
>
>         entry->ptr = object;
>
> --
> 2.25.1
>