From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756826AbcCCEXH (ORCPT ); Wed, 2 Mar 2016 23:23:07 -0500 Received: from mx1.redhat.com ([209.132.183.28]:53469 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756613AbcCCEXE (ORCPT ); Wed, 2 Mar 2016 23:23:04 -0500 Date: Thu, 3 Mar 2016 09:53:00 +0530 From: Pratyush Anand To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, linux-rt-users , Thomas Gleixner , Carsten Emde , Sebastian Andrzej Siewior , John Kacur , Paul Gortmaker , stable-rt@vger.kernel.org, Yang Shi Subject: Re: [PATCH RT 07/17] arm64: replace read_lock to rcu lock in call_step_hook Message-ID: <20160303042300.GA32034@dhcppc3> References: <20160302154433.638594715@goodmis.org> <20160302154500.885242090@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160302154500.885242090@goodmis.org> User-Agent: Mutt/1.5.24 (2015-08-30) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Thu, 03 Mar 2016 04:23:03 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Steven, On 02/03/2016:10:44:40 AM, Steven Rostedt wrote: > 3.14.61-rt64-rc1 stable review patch. > If anyone has any objections, please let me know. > > ------------------ > > From: Yang Shi > > BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:917 > in_atomic(): 1, irqs_disabled(): 128, pid: 383, name: sh > Preemption disabled at:[] kgdb_cpu_enter+0x158/0x6b8 > > CPU: 3 PID: 383 Comm: sh Tainted: G W 4.1.13-rt13 #2 > Hardware name: Freescale Layerscape 2085a RDB Board (DT) > Call trace: > [] dump_backtrace+0x0/0x128 > [] show_stack+0x24/0x30 > [] dump_stack+0x80/0xa0 > [] ___might_sleep+0x18c/0x1a0 > [] __rt_spin_lock+0x2c/0x40 > [] rt_read_lock+0x40/0x58 > [] single_step_handler+0x38/0xd8 > [] do_debug_exception+0x58/0xb8 > Exception stack(0xffff80834a1e7c80 to 0xffff80834a1e7da0) > 7c80: ffffff9c ffffffff 92c23ba0 0000ffff 4a1e7e40 ffff8083 001bfcc4 ffff8000 > 7ca0: f2000400 00000000 00000000 00000000 4a1e7d80 ffff8083 0049501c ffff8000 > 7cc0: 00005402 00000000 00aaa210 ffff8000 4a1e7ea0 ffff8083 000833f4 ffff8000 > 7ce0: ffffff9c ffffffff 92c23ba0 0000ffff 4a1e7ea0 ffff8083 001bfcc0 ffff8000 > 7d00: 4a0fc400 ffff8083 00005402 00000000 4a1e7d40 ffff8083 00490324 ffff8000 > 7d20: ffffff9c 00000000 92c23ba0 0000ffff 000a0000 00000000 00000000 00000000 > 7d40: 00000008 00000000 00080000 00000000 92c23b8b 0000ffff 92c23b8e 0000ffff > 7d60: 00000038 00000000 00001cb2 00000000 00000005 00000000 92d7b498 0000ffff > 7d80: 01010101 01010101 92be9000 0000ffff 00000000 00000000 00000030 00000000 > [] el1_dbg+0x18/0x6c > > This issue is similar with 62c6c61("arm64: replace read_lock to rcu lock in > call_break_hook"), but comes to single_step_handler. > > This also solves kgdbts boot test silent hang issue on 4.4 -rt kernel. > > Cc: stable-rt@vger.kernel.org > Signed-off-by: Yang Shi > Signed-off-by: Sebastian Andrzej Siewior > Signed-off-by: Steven Rostedt > --- > arch/arm64/kernel/debug-monitors.c | 21 ++++++++++++--------- > 1 file changed, 12 insertions(+), 9 deletions(-) > > diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c > index 636ba8b6240b..f66d668ffce9 100644 > --- a/arch/arm64/kernel/debug-monitors.c > +++ b/arch/arm64/kernel/debug-monitors.c > @@ -190,19 +190,22 @@ static void clear_regs_spsr_ss(struct pt_regs *regs) > /* EL1 Single Step Handler hooks */ > static LIST_HEAD(step_hook); > DEFINE_RWLOCK(step_hook_lock); > +static DEFINE_RWLOCK(step_hook_lock); I think, this got wrong during backporting, no? Should have been -DEFINE_RWLOCK(step_hook_lock); > +static DEFINE_SPINLOCK(step_hook_lock); ~Pratyush