From: Dmitry Vyukov <dvyukov@google.com>
To: Walter Wu <walter-zh.wu@mediatek.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>,
Alexander Potapenko <glider@google.com>,
Matthias Brugger <matthias.bgg@gmail.com>,
Andrey Konovalov <andreyknvl@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Jens Axboe <axboe@kernel.dk>, Oleg Nesterov <oleg@redhat.com>,
kasan-dev <kasan-dev@googlegroups.com>,
Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
wsd_upstream <wsd_upstream@mediatek.com>,
linux-mediatek@lists.infradead.org
Subject: Re: [PATCH v2] task_work: kasan: record task_work_add() call stack
Date: Tue, 16 Mar 2021 07:34:39 +0100 [thread overview]
Message-ID: <CACT4Y+aMKH24F6DO=iKX0jDmxm4MCuJkA-OTkmgbfDm73LLKhQ@mail.gmail.com> (raw)
In-Reply-To: <20210316024410.19967-1-walter-zh.wu@mediatek.com>
On Tue, Mar 16, 2021 at 3:44 AM Walter Wu <walter-zh.wu@mediatek.com> wrote:
>
> Why record task_work_add() call stack?
> Syzbot reports many use-after-free issues for task_work, see [1].
> After see the free stack and the current auxiliary stack, we think
> they are useless, we don't know where register the work, this work
> may be the free call stack, so that we miss the root cause and
> don't solve the use-after-free.
>
> Add task_work_add() call stack into KASAN auxiliary stack in
> order to improve KASAN report. It is useful for programmers
> to solve use-after-free issues.
>
> [1]: https://groups.google.com/g/syzkaller-bugs/search?q=kasan%20use-after-free%20task_work_run
>
> Signed-off-by: Walter Wu <walter-zh.wu@mediatek.com>
> Suggested-by: Dmitry Vyukov <dvyukov@google.com>
> Cc: Andrey Konovalov <andreyknvl@google.com>
> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
> Cc: Dmitry Vyukov <dvyukov@google.com>
> Cc: Alexander Potapenko <glider@google.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Matthias Brugger <matthias.bgg@gmail.com>
> Cc: Jens Axboe <axboe@kernel.dk>
> Cc: Oleg Nesterov <oleg@redhat.com>
> ---
>
> v2: Fix kasan_record_aux_stack() calling sequence issue.
> Thanks for Dmitry's suggestion
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
> ---
> kernel/task_work.c | 3 +++
> mm/kasan/kasan.h | 2 +-
> 2 files changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/task_work.c b/kernel/task_work.c
> index 9cde961875c0..3d4852891fa8 100644
> --- a/kernel/task_work.c
> +++ b/kernel/task_work.c
> @@ -34,6 +34,9 @@ int task_work_add(struct task_struct *task, struct callback_head *work,
> {
> struct callback_head *head;
>
> + /* record the work call stack in order to print it in KASAN reports */
> + kasan_record_aux_stack(work);
> +
> do {
> head = READ_ONCE(task->task_works);
> if (unlikely(head == &work_exited))
> diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
> index 3436c6bf7c0c..e4629a971a3c 100644
> --- a/mm/kasan/kasan.h
> +++ b/mm/kasan/kasan.h
> @@ -146,7 +146,7 @@ struct kasan_alloc_meta {
> struct kasan_track alloc_track;
> #ifdef CONFIG_KASAN_GENERIC
> /*
> - * call_rcu() call stack is stored into struct kasan_alloc_meta.
> + * The auxiliary stack is stored into struct kasan_alloc_meta.
> * The free stack is stored into struct kasan_free_meta.
> */
> depot_stack_handle_t aux_stack[2];
> --
> 2.18.0
>
> --
> You received this message because you are subscribed to the Google Groups "kasan-dev" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to kasan-dev+unsubscribe@googlegroups.com.
> To view this discussion on the web visit https://groups.google.com/d/msgid/kasan-dev/20210316024410.19967-1-walter-zh.wu%40mediatek.com.
next prev parent reply other threads:[~2021-03-16 6:34 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-16 2:44 [PATCH v2] task_work: kasan: record task_work_add() call stack Walter Wu
2021-03-16 6:34 ` Dmitry Vyukov [this message]
2021-03-16 14:33 ` Jens Axboe
2021-03-16 17:54 ` Oleg Nesterov
2021-03-18 0:30 ` Andrey Konovalov
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