Re: [Qemu-devel] [PATCH for-2.9] sheepdog: Fix crash in co_read_response()

[Peter Maydell]

On 11 April 2017 at 15:08, Kevin Wolf <address@hidden> wrote:
> This fixes a regression introduced in commit 9d456654.
>
> aio_co_wake() can only be used to reenter a coroutine that was already
> previously entered, otherwise co->ctx is uninitialised and we access
> garbage. Using it immediately after qemu_coroutine_create() like in
> co_read_response() is wrong and causes segfaults.
>
> Replace the call with aio_co_enter(), which gets an explicit AioContext
> parameter and works even for new coroutines.
>
> Signed-off-by: Kevin Wolf <address@hidden>
> Tested-by: Kashyap Chamarthy <address@hidden>
> ---
>  block/sheepdog.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/block/sheepdog.c b/block/sheepdog.c
> index 1b71fc8..142eb4f 100644
> --- a/block/sheepdog.c
> +++ b/block/sheepdog.c
> @@ -942,7 +942,7 @@ static void co_read_response(void *opaque)
>          s->co_recv = qemu_coroutine_create(aio_read_response, opaque);
>      }
>
> -    aio_co_wake(s->co_recv);
> +    aio_co_enter(s->aio_context, s->co_recv);
>  }
>
>  static void co_write_request(void *opaque)
> --
> 1.8.3.1
>

Applied, thanks.

-- PMM