<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - BadAccess errors in ShmAttach due to thread races with XNextRequest() usage in cairo-xlib-surface-shm.c" href="https://bugs.freedesktop.org/show_bug.cgi?id=98883#c18">Comment # 18</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - BadAccess errors in ShmAttach due to thread races with XNextRequest() usage in cairo-xlib-surface-shm.c" href="https://bugs.freedesktop.org/show_bug.cgi?id=98883">bug 98883</a> from <a class="email" href="mailto:daniel.van.vugt@canonical.com" title="Daniel van Vugt <daniel.van.vugt@canonical.com>"> Daniel van Vugt</a> <pre>> XShmAttach returns True to indicate it successfully queued the request. > It does not fail to queue the request. > > If the server fails to process the request successfully, then it sends an > error response. > > It would be helpful to understand why you are expecting an error response. Essentially we have the Xorg server process having its privileges demoted and re-promoted. If the XShmAttach request comes in while it is demoted then it can't complete the request and returns BadAccess to the client. The client initiated the request from _cairo_xlib_shm_pool_create but has since (asynchronously) moved on to other code. So it crashes in an unpredictable location when the BadAccess eventually comes in from the server. I am happy with your explanation that "XShmAttach returns True to indicate it successfully queued the request". However I don't believe the same applies to _cairo_xlib_shm_pool_create, so I think any final fix would have to happen in that function still.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> </ul> </body> </html>