From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49221) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XcddA-0007ox-MF for qemu-devel@nongnu.org; Fri, 10 Oct 2014 13:05:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Xcdd4-0002w8-Ci for qemu-devel@nongnu.org; Fri, 10 Oct 2014 13:05:28 -0400 Received: from mx1.redhat.com ([209.132.183.28]:32329) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Xcdd4-0002vP-6O for qemu-devel@nongnu.org; Fri, 10 Oct 2014 13:05:22 -0400 From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Date: Fri, 10 Oct 2014 19:05:11 +0200 Message-Id: <1412960711-18636-1-git-send-email-marcandre.lureau@gmail.com> Subject: [Qemu-devel] [PATCH] qxl: keep going if reaching guest bug on empty area List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , kraxel@redhat.com Xorg server hangs when using xfig and typing a text with space: #0 qxl_wait_for_io_command (qxl=) at qxl_io.c:47 #1 0x00007f826a49a299 in qxl_download_box (surface=0x221d030, x1=231, y1=259, x2=, y2=) at qxl_surface.c:143 while (!(ram_header->int_pending & QXL_INTERRUPT_IO_CMD)) usleep (1); The QXL driver is calling QXL_IO_UPDATE_AREA with an empty area. This is a guest bug. The call is async and no ack is sent back on guest bug, so the X server will hang. The driver should be improved to avoid this situation and also to abort on QXL_INTERRUPT_ERROR. This will be a different patch series for the driver. However, it is simple enough to keep qemu running on empty areas update, which is what this patch provides. https://bugzilla.redhat.com/show_bug.cgi?id=1151363 --- hw/display/qxl.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/hw/display/qxl.c b/hw/display/qxl.c index 93b3518..b540dd6 100644 --- a/hw/display/qxl.c +++ b/hw/display/qxl.c @@ -1591,6 +1591,11 @@ async_common: qxl_set_guest_bug(d, "QXL_IO_UPDATE_AREA: invalid area (%ux%u)x(%ux%u)\n", update.left, update.top, update.right, update.bottom); + if (update.left == update.right || update.top == update.bottom) { + /* old drivers may provide empty area, keep going */ + qxl_clear_guest_bug(d); + goto cancel_async; + } break; } if (async == QXL_ASYNC) { -- 1.9.3