Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754775Ab0GBWSL (ORCPT ); Fri, 2 Jul 2010 18:18:11 -0400 Received: from mail-qy0-f174.google.com ([209.85.216.174]:41333 "EHLO mail-qy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752582Ab0GBWSJ (ORCPT ); Fri, 2 Jul 2010 18:18:09 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:content-type; b=xkp5P/6Jb4E4KoyRI05ZRmQtmoKINrrmSroXxXW86uAaPbbAmBmqxgLaSyZ1Ib9vfL aNMwda1WmHegiIlhJjfVJLbNDQEjxBHM3iQOE/R/TVjEpFk7dQizohzLnwjkv02pGf7r y/2HavT9DW4zCNAExVcZ4BExUo0JT6IvWCUrg= MIME-Version: 1.0 Date: Fri, 2 Jul 2010 16:18:05 -0600 Message-ID: Subject: 2.6.34 rex64 sysret instruction setup not preserving flags (r11 contents and eflags do not match) From: Jeffrey Merkey To: linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 785 Lines: 18 On an AMD64 based system executing int 1 exceptions across a rex64 sysret, if the debugger sets the trap flag, r11 which holds the eflags values for the sysret return from syscall, the flags do not appear to get set resutling in the int exception nesting by calling sysret over and over again until the kernel stack runs off the end. Looks like the resume did not get set on this instruction. sysret on AMD requires the flags be saved into r11 and what I am seeing is the flags not matching what has been set in the pt_regs struct. Jeff -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/