From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 22870 invoked by alias); 20 Feb 2012 22:08:37 -0000 Received: (qmail 22857 invoked by uid 22791); 20 Feb 2012 22:08:36 -0000 X-SWARE-Spam-Status: No, hits=-2.8 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00,TW_MJ X-Spam-Check-By: sourceware.org Received: from localhost (HELO sourceware.org) (127.0.0.1) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Mon, 20 Feb 2012 22:08:24 +0000 From: "mjw at redhat dot com" To: systemtap@sourceware.org Subject: [Bug runtime/13714] panic when sampling backtrace() in timer.profile Date: Mon, 20 Feb 2012 22:08:00 -0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: systemtap X-Bugzilla-Component: runtime X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: mjw at redhat dot com X-Bugzilla-Status: ASSIGNED X-Bugzilla-Priority: P2 X-Bugzilla-Assigned-To: mjw at redhat dot com X-Bugzilla-Target-Milestone: --- X-Bugzilla-Changed-Fields: Status AssignedTo Message-ID: In-Reply-To: References: X-Bugzilla-URL: http://sourceware.org/bugzilla/ Auto-Submitted: auto-generated Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org X-SW-Source: 2012-q1/txt/msg00162.txt.bz2 http://sourceware.org/bugzilla/show_bug.cgi?id=13714 Mark Wielaard changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |ASSIGNED AssignedTo|systemtap at sourceware dot |mjw at redhat dot com |org | --- Comment #2 from Mark Wielaard 2012-02-20 22:08:21 UTC --- Found the root cause of this issue. It happens when a DW_CFA operation that defines the CFA as dwarf expression is followed by a DW_CFA operation that (re)defined the CFA as register+offset. In that case we forgot the reset the REG_STATE.cfa_is_expr flag which made compute_expr() interpret the reg/offset as expr pointer (because they share their values in a union). While adding more sanity checks to make sure we catch such issues I found what looks like bad CFI in the x86_64 kernel in common_interrupt (arch/x86/kernel/entry_64.S) which defines CFI "by hand" and has a CFI_DEF_CFA_REGISTER following a def_cfa_expression, which is invalid. -- Configure bugmail: http://sourceware.org/bugzilla/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the assignee for the bug.