Re: [PATCH] baum: Fix crash when Braille output is not available

[Thomas Huth <thuth@redhat.com>]

On 10/03/2021 17.08, Samuel Thibault wrote:
> When Braille output is not available, the backend properly reports being
> unable to be created, but 5f8e93c3e262 ("util/qemu-timer: Make timer_free()
> imply timer_del()") made the timer_free() call now refuse any NULL
> parameter. char_braille_finalize thus now has to be more careful with
> calling it on baum->cellCount_timer.
> 
> Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
> ---
>   chardev/baum.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/chardev/baum.c b/chardev/baum.c
> index 5deca778bc..aca5bf12fb 100644
> --- a/chardev/baum.c
> +++ b/chardev/baum.c
> @@ -631,7 +631,9 @@ static void char_braille_finalize(Object *obj)
>   {
>       BaumChardev *baum = BAUM_CHARDEV(obj);
>   
> -    timer_free(baum->cellCount_timer);
> +    if (baum->cellCount_timer) {
> +        timer_free(baum->cellCount_timer);
> +    }
>       if (baum->brlapi) {
>           brlapi__closeConnection(baum->brlapi);
>           g_free(baum->brlapi);

I just tried to debug this problem, too, and came to the same conclusion.

Reviewed-by: Thomas Huth <thuth@redhat.com>