From patchwork Mon Mar 29 07:58:16 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 411626 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EF634C433F4 for ; Mon, 29 Mar 2021 08:04:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 74DA86197C for ; Mon, 29 Mar 2021 08:04:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231963AbhC2IDf (ORCPT ); Mon, 29 Mar 2021 04:03:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:45862 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231996AbhC2IDM (ORCPT ); Mon, 29 Mar 2021 04:03:12 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id E8356619AA; Mon, 29 Mar 2021 08:03:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1617004992; bh=A6LnIq9Ny7Qd4Rzyprd6DSPguREoTQjKIkCsXOZZAvc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qY7d3A6nU4+xXSL+nUfuSVvdI8t75cAhkBTuv8oHb5eDEqelAULBz3frhXGzm41mR /trNcC8cB+ejIpX444ShoaIqcX2aAlL4T7rv2+/9vR+RpJQI4r6Sv85pSqkEubgbyP PVDVr2P7Cnz5oTwYIszXAixvZ1p+SMZtOJAKyPnw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Alexander Levin , Thomas Gleixner , "Peter Zijlstra (Intel)" , Linus Torvalds , Ingo Molnar , Ben Hutchings Subject: [PATCH 4.9 41/53] futex: Avoid freeing an active timer Date: Mon, 29 Mar 2021 09:58:16 +0200 Message-Id: <20210329075608.863398296@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210329075607.561619583@linuxfoundation.org> References: <20210329075607.561619583@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Thomas Gleixner commit 97181f9bd57405b879403763284537e27d46963d upstream. Alexander reported a hrtimer debug_object splat: ODEBUG: free active (active state 0) object type: hrtimer hint: hrtimer_wakeup (kernel/time/hrtimer.c:1423) debug_object_free (lib/debugobjects.c:603) destroy_hrtimer_on_stack (kernel/time/hrtimer.c:427) futex_lock_pi (kernel/futex.c:2740) do_futex (kernel/futex.c:3399) SyS_futex (kernel/futex.c:3447 kernel/futex.c:3415) do_syscall_64 (arch/x86/entry/common.c:284) entry_SYSCALL64_slow_path (arch/x86/entry/entry_64.S:249) Which was caused by commit: cfafcd117da0 ("futex: Rework futex_lock_pi() to use rt_mutex_*_proxy_lock()") ... losing the hrtimer_cancel() in the shuffle. Where previously the hrtimer_cancel() was done by rt_mutex_slowlock() we now need to do it manually. Reported-by: Alexander Levin Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Fixes: cfafcd117da0 ("futex: Rework futex_lock_pi() to use rt_mutex_*_proxy_lock()") Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1704101802370.2906@nanos Signed-off-by: Ingo Molnar Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman --- kernel/futex.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/kernel/futex.c +++ b/kernel/futex.c @@ -3018,8 +3018,10 @@ out_unlock_put_key: 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: