On Wed, Sep 05, 2012 at 02:01:36PM -0500, Anthony Liguori wrote:
> Commit c3767ed0eb5d0bb25fe409ae5dec06e3411ff1b6 introduced a possible SEGV
> when
> using a socket chardev with server=on because it assumes that all TCP sockets
> are in client mode.
>
> This patch adds a check to only reconnect when in client mode.
>
> Cc: Lei Li <li...@linux.vnet.ibm.com>
> Reported-by: Michael Roth <mdr...@linux.vnet.ibm.com>
> Signed-off-by: Anthony Liguori <aligu...@us.ibm.com>
> ---
> qemu-char.c | 4 +++-
> 1 files changed, 3 insertions(+), 1 deletions(-)
>
> diff --git a/qemu-char.c b/qemu-char.c
> index 398baf1..767da93 100644
> --- a/qemu-char.c
> +++ b/qemu-char.c
> @@ -2148,10 +2148,12 @@ static int tcp_chr_write(CharDriverState *chr, const
> uint8_t *buf, int len)
> TCPCharDriver *s = chr->opaque;
> if (s->connected) {
> return send_all(s->fd, buf, len);
> - } else {
> + } else if (s->listen_fd == -1) {
> /* (Re-)connect for unconnected writing */
> tcp_chr_connect(chr);
> return 0;
> + } else {
> + return len;
> }
> }
Hi Anthony,
I just came around this patch when I was trying to fix this
bug: https://bugzilla.redhat.com/show_bug.cgi?id=853408
qemu segfaults when trying to write to a serial socket which
is *not* a server socket and has been closed by the other end.
Unfortunately your patch above does not fix it. Only a
complete revert of c3767ed0eb5d0 fixes it.
I don't understand the purpose of c3767ed0eb5d0 at all. It
seems to set the s->connected flag and carries on regardless,
happily calling write (-1, ...), which is completely broken.
The other end closed the socket. There's no one listening on the
other end, and setting the s->connected flag will not help that.
Rich.
--
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