From patchwork Thu Mar 24 11:14:50 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: He Kuang X-Patchwork-Id: 64335 Delivered-To: patch@linaro.org Received: by 10.112.199.169 with SMTP id jl9csp567923lbc; Thu, 24 Mar 2016 04:15:47 -0700 (PDT) X-Received: by 10.66.140.39 with SMTP id rd7mr11775626pab.92.1458818147049; Thu, 24 Mar 2016 04:15:47 -0700 (PDT) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id 13si11635584pft.59.2016.03.24.04.15.46; Thu, 24 Mar 2016 04:15:47 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of stable-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of stable-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=stable-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755882AbcCXLPq (ORCPT + 3 others); Thu, 24 Mar 2016 07:15:46 -0400 Received: from szxga04-in.huawei.com ([58.251.152.52]:61790 "EHLO szxga04-in.huawei.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1754769AbcCXLPp (ORCPT ); Thu, 24 Mar 2016 07:15:45 -0400 Received: from 172.24.1.46 (EHLO lggeml428-hub.china.huawei.com) ([172.24.1.46]) by szxrg04-dlp.huawei.com (MOS 4.4.6-GA FastPath queued) with ESMTP id AVM19842; Thu, 24 Mar 2016 19:12:13 +0800 (CST) Received: from euler.hulk-profiling (10.107.193.250) by lggeml428-hub.china.huawei.com (10.72.61.80) with Microsoft SMTP Server id 14.3.235.1; Thu, 24 Mar 2016 19:15:22 +0800 From: He Kuang To: CC: , , Subject: [PATCH 2/5] arm64: replace read_lock to rcu lock in call_step_hook Date: Thu, 24 Mar 2016 11:14:50 +0000 Message-ID: <1458818093-7419-3-git-send-email-hekuang@huawei.com> X-Mailer: git-send-email 1.8.3.4 In-Reply-To: <1458818093-7419-1-git-send-email-hekuang@huawei.com> References: <1458818093-7419-1-git-send-email-hekuang@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.107.193.250] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020203.56F3CC55.0262, ss=1, re=0.000, recu=0.000, reip=0.000, cl=1, cld=1, fgs=0, ip=0.0.0.0, so=2014-11-16 11:51:01, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: c15aa8055bdfa8641e9571f086f02728 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Yang Shi [ Upstream commit cf0a25436f05753aca5151891aea4fd130556e2a ] 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. Signed-off-by: Yang Shi Acked-by: Will Deacon Signed-off-by: Catalin Marinas Signed-off-by: He Kuang --- arch/arm64/kernel/debug-monitors.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) -- 1.8.5.2 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c index 70654d84..0d1d675 100644 --- a/arch/arm64/kernel/debug-monitors.c +++ b/arch/arm64/kernel/debug-monitors.c @@ -184,20 +184,21 @@ static void clear_regs_spsr_ss(struct pt_regs *regs) /* EL1 Single Step Handler hooks */ static LIST_HEAD(step_hook); -static DEFINE_RWLOCK(step_hook_lock); +static DEFINE_SPINLOCK(step_hook_lock); void register_step_hook(struct step_hook *hook) { - write_lock(&step_hook_lock); - list_add(&hook->node, &step_hook); - write_unlock(&step_hook_lock); + spin_lock(&step_hook_lock); + list_add_rcu(&hook->node, &step_hook); + spin_unlock(&step_hook_lock); } void unregister_step_hook(struct step_hook *hook) { - write_lock(&step_hook_lock); - list_del(&hook->node); - write_unlock(&step_hook_lock); + spin_lock(&step_hook_lock); + list_del_rcu(&hook->node); + spin_unlock(&step_hook_lock); + synchronize_rcu(); } /* @@ -211,15 +212,15 @@ static int call_step_hook(struct pt_regs *regs, unsigned int esr) struct step_hook *hook; int retval = DBG_HOOK_ERROR; - read_lock(&step_hook_lock); + rcu_read_lock(); - list_for_each_entry(hook, &step_hook, node) { + list_for_each_entry_rcu(hook, &step_hook, node) { retval = hook->fn(regs, esr); if (retval == DBG_HOOK_HANDLED) break; } - read_unlock(&step_hook_lock); + rcu_read_unlock(); return retval; }