<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#c11">Comment # 11</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>It's been a few months so my memory is not completely clear. I do however think Uli's statement is incorrect in the final two sentences: > What the patch does is to make XShmAttach synchronous (aka "slow"). I do not > know why, but nothing in this bug report suggests that this is necessary. > The description of the patch does not say anything about this either. > XShmAttach() should not just randomly fail, so why does the patch try to > handle random failures? <a href="attachment.cgi?id=139297" name="attach_139297" title="Handle-XShmAttach-failures-v1.patch">attachment 139297</a> <a href="attachment.cgi?id=139297&action=edit" title="Handle-XShmAttach-failures-v1.patch">[details]</a> <a href='page.cgi?id=splinter.html&bug=98883&attachment=139297'>[review]</a> mentions multiple times "why" it is necessary to make it synchronous. Because it's impossible to detect errors in XShmAttach otherwise. It's possible we're using to the wrong bug here, but I believe the patch is still correct and we have no choice but to make XShmAttach slow. You can only choose between maximum performance or reliable error handling, and not have both. The reasons are detailed in <a href="attachment.cgi?id=139297" name="attach_139297" title="Handle-XShmAttach-failures-v1.patch">attachment 139297</a> <a href="attachment.cgi?id=139297&action=edit" title="Handle-XShmAttach-failures-v1.patch">[details]</a> <a href='page.cgi?id=splinter.html&bug=98883&attachment=139297'>[review]</a>.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> </ul> </body> </html>