From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754582AbdDJQDp (ORCPT ); Mon, 10 Apr 2017 12:03:45 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:51751 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753340AbdDJQDn (ORCPT ); Mon, 10 Apr 2017 12:03:43 -0400 Date: Mon, 10 Apr 2017 18:03:36 +0200 (CEST) From: Thomas Gleixner To: alexander.levin@verizon.com cc: Peter Zijlstra , "mingo@kernel.org" , "juri.lelli@arm.com" , "rostedt@goodmis.org" , "xlpang@redhat.com" , "bigeasy@linutronix.de" , "linux-kernel@vger.kernel.org" , "mathieu.desnoyers@efficios.com" , "jdesfossez@efficios.com" , "bristot@redhat.com" , "dvhart@infradead.org" Subject: Re: [PATCH -v6 11/13] futex: Rework futex_lock_pi() to use rt_mutex_*_proxy_lock() In-Reply-To: <20170410155146.ivj3vggoacrzq624@sasha-lappy> Message-ID: References: <20170322103547.756091212@infradead.org> <20170322104152.062785528@infradead.org> <20170410155146.ivj3vggoacrzq624@sasha-lappy> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 10 Apr 2017, alexander.levin@verizon.com wrote: > On Wed, Mar 22, 2017 at 11:35:58AM +0100, Peter Zijlstra wrote: > > By changing futex_lock_pi() to use rt_mutex_*_proxy_lock() we arrive > > at a point where all wait_list modifications are done under both > > hb->lock and wait_lock. > [...] > > Hey Peter, > > I'm seeing the following, which seems to be related to this patch: > > [ 21.762875] ODEBUG: free active (active state 0) object type: hrtimer hint: hrtimer_wakeup (kernel/time/hrtimer.c:1423) > [ 21.788050] debug_object_free (lib/debugobjects.c:603) > [ 21.791105] destroy_hrtimer_on_stack (kernel/time/hrtimer.c:427) > [ 21.791746] futex_lock_pi (kernel/futex.c:2740) > [ 21.800721] do_futex (kernel/futex.c:3399) > [ 21.818395] SyS_futex (kernel/futex.c:3447 kernel/futex.c:3415) > [ 21.822260] do_syscall_64 (arch/x86/entry/common.c:284) > [ 21.827328] entry_SYSCALL64_slow_path (arch/x86/entry/entry_64.S:249) Yep, that rework dropped the hrtimer cancel. Fix below. Thanks, tglx 8<------------------------ diff --git a/kernel/futex.c b/kernel/futex.c index c3eebcdac206..7ac167683c9f 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -2736,8 +2736,10 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags, out_put_key: put_futex_key(&q.key); out: - if (to) + if (to) { + hrtimer_cancel(&to->timer); destroy_hrtimer_on_stack(&to->timer); + } return ret != -EINTR ? ret : -ERESTARTNOINTR; uaddr_faulted: