From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932586Ab0JFJeW (ORCPT ); Wed, 6 Oct 2010 05:34:22 -0400 Received: from lennier.cc.vt.edu ([198.82.162.213]:54886 "EHLO lennier.cc.vt.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757940Ab0JFJeU (ORCPT ); Wed, 6 Oct 2010 05:34:20 -0400 X-Mailer: exmh version 2.7.2 01/07/2005 with nmh-1.2 To: Andrew Morton , Peter Zijlstra , Paul Mackerras , Ingo Molnar , Arnaldo Carvalho de Melo Cc: linux-kernel@vger.kernel.org Subject: 2.6.36-rc5-mmotm0928 BUG while trying to ptrace a process From: Valdis.Kletnieks@vt.edu Mime-Version: 1.0 Content-Type: multipart/signed; boundary="==_Exmh_1286357577_11346P"; micalg=pgp-sha1; protocol="application/pgp-signature" Content-Transfer-Encoding: 7bit Date: Wed, 06 Oct 2010 05:32:57 -0400 Message-ID: <108598.1286357577@localhost> X-Mirapoint-Received-SPF: 128.173.34.98 localhost Valdis.Kletnieks@vt.edu 2 pass X-Mirapoint-IP-Reputation: reputation=neutral-1, source=Fixed, refid=n/a, actions=MAILHURDLE SPF TAG X-Junkmail-Status: score=10/50, host=vivi.cc.vt.edu X-Junkmail-SD-Raw: score=unknown, refid=str=0001.0A020201.4CAC424A.00CB,ss=1,fgs=0, ip=0.0.0.0, so=2009-09-22 00:05:22, dmn=2009-09-10 00:05:08, mode=single engine X-Junkmail-IWF: false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --==_Exmh_1286357577_11346P Content-Type: text/plain; charset=us-ascii Dell Latitude E6500, Intel Core2 Duo P8700 CPU. Have seen this three times now while trying to attach gdb to a hung Firefox process. [20669.480674] BUG: unable to handle kernel NULL pointer dereference at 0000000000000100 [20669.480682] IP: [] __reserve_bp_slot+0x56/0x17d Here's the stack traceback: [20669.480761] Process gdb (pid: 60320, threadinfo ffff8800a0e4c000, task ffff8800c62acc80) [20669.480763] Stack: [20669.480765] ffff8801188c2eac ffffffff81a40750 0000000100000000 ffffffff81a406b0 [20669.480771] <0> ffffffff8100b469 ffff8800a0d6c400 0000000000000000 ffffffff81a406b0 [20669.480777] <0> ffffffff8100b469 0000000000000000 ffff8800a0e4dcf8 ffffffff810b83e5 [20669.480784] Call Trace: [20669.480789] [] ? ptrace_triggered+0x0/0x39 [20669.480793] [] ? ptrace_triggered+0x0/0x39 [20669.480797] [] reserve_bp_slot+0x22/0x3b [20669.480800] [] ? perf_init_event+0x0/0xc9 [20669.480804] [] register_perf_hw_breakpoint+0x11/0x36 [20669.480808] [] hw_breakpoint_event_init+0x1f/0x34 [20669.480811] [] ? ptrace_triggered+0x0/0x39 [20669.480815] [] perf_init_event+0x55/0xc9 [20669.480818] [] ? perf_init_event+0x0/0xc9 [20669.480822] [] perf_event_alloc+0x1a6/0x3ef [20669.480826] [] perf_event_create_kernel_counter+0x22/0x185 [20669.480830] [] register_user_hw_breakpoint+0xf/0x11 [20669.480834] [] ptrace_set_debugreg+0xaa/0x257 [20669.480838] [] ? sub_preempt_count+0x35/0x48 [20669.480844] [] ? _raw_spin_unlock_irqrestore+0x72/0x80 [20669.480848] [] arch_ptrace+0x126/0x214 [20669.480852] [] sys_ptrace+0x7e/0x99 [20669.480857] [] system_call_fastpath+0x16/0x1b Any thoughts? I haven't gotten any further than "the big honking commits against perf in linux-next". Probably bisectable with some effort - I've got a fairly replicable Firefox hang that seems to trigger the gdb indigestion., --==_Exmh_1286357577_11346P Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Exmh version 2.5 07/13/2001 iD8DBQFMrEJJcC3lWbTT17ARAhCQAJ9+60uLVy4Sk+iTnVY31836l9587wCdG4Sb KYerzz92WjQNZV0pUUDOMyc= =Z4bk -----END PGP SIGNATURE----- --==_Exmh_1286357577_11346P--