On 11 July 2014 05:58, Liliang <liangx.z...@intel.com> wrote:
> From: Li Liang <liangx.z...@intel.com>
>
> This bug was introduced in the commit
> 9005b2a7589540a3733b3abdcfbccfe7746cd1a1,
> it will cause deadlock when create a vm with the parameter "-monitor pty" and
> then try to read from /dev/pts/x.
>
> Signed-off-by: Li Liang <liangx.z...@intel.com>
> ---
> qemu-char.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/qemu-char.c b/qemu-char.c
> index 55e372c..55cdded 100644
> --- a/qemu-char.c
> +++ b/qemu-char.c
> @@ -1103,9 +1103,11 @@ static gboolean pty_chr_timer(gpointer opaque)
> s->timer_tag = 0;
> if (!s->connected) {
> /* Next poll ... */
> + qemu_mutex_unlock(&chr->chr_write_lock);
> pty_chr_update_read_handler_locked(chr);
> + } else {
> + qemu_mutex_unlock(&chr->chr_write_lock);
> }
> - qemu_mutex_unlock(&chr->chr_write_lock);
> return FALSE;
> }
This is clearly not the correct fix -- it is now calling
pty_chr_update_read_handler_locked() without holding
the chr_write_lock mutex, which is not permitted.
thanks
-- PMM
