From patchwork Sat Mar 26 17:28:47 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sasha Levin X-Patchwork-Id: 64503 Delivered-To: patch@linaro.org Received: by 10.112.199.169 with SMTP id jl9csp709628lbc; Sat, 26 Mar 2016 10:30:42 -0700 (PDT) X-Received: by 10.66.90.163 with SMTP id bx3mr30102782pab.59.1459013408274; Sat, 26 Mar 2016 10:30:08 -0700 (PDT) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id f63si2362197pfj.137.2016.03.26.10.30.07; Sat, 26 Mar 2016 10:30:08 -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 S1753620AbcCZRaE (ORCPT + 3 others); Sat, 26 Mar 2016 13:30:04 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:23247 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753972AbcCZR3u (ORCPT ); Sat, 26 Mar 2016 13:29:50 -0400 Received: from userv0021.oracle.com (userv0021.oracle.com [156.151.31.71]) by aserp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id u2QHTYZm030978 (version=TLSv1 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Sat, 26 Mar 2016 17:29:35 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by userv0021.oracle.com (8.13.8/8.13.8) with ESMTP id u2QHTYAp011250 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Sat, 26 Mar 2016 17:29:34 GMT Received: from abhmp0014.oracle.com (abhmp0014.oracle.com [141.146.116.20]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id u2QHTXSf031360; Sat, 26 Mar 2016 17:29:34 GMT Received: from localhost.localdomain (/73.159.178.34) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Sat, 26 Mar 2016 10:29:33 -0700 From: Sasha Levin To: stable@vger.kernel.org, stable-commits@vger.kernel.org Cc: Yang Shi , Catalin Marinas , He Kuang , Sasha Levin Subject: [added to the 4.1 stable tree] arm64: replace read_lock to rcu lock in call_step_hook Date: Sat, 26 Mar 2016 13:28:47 -0400 Message-Id: <1459013330-15318-43-git-send-email-sasha.levin@oracle.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1459013330-15318-1-git-send-email-sasha.levin@oracle.com> References: <1459013330-15318-1-git-send-email-sasha.levin@oracle.com> X-Source-IP: userv0021.oracle.com [156.151.31.71] Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Yang Shi This patch has been added to the 4.1 stable tree. If you have any objections, please let us know. -- 2.5.0 -- 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 =============== [ 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 Signed-off-by: Sasha Levin --- arch/arm64/kernel/debug-monitors.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) 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; }