Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751828AbdFAQJQ (ORCPT ); Thu, 1 Jun 2017 12:09:16 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:33573 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752229AbdFAPpI (ORCPT ); Thu, 1 Jun 2017 11:45:08 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Michael Ellerman" , "Ravi Bangoria" Date: Thu, 01 Jun 2017 16:43:16 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 126/212] powerpc/xmon: Fix data-breakpoint In-Reply-To: X-SA-Exim-Connect-IP: 82.70.136.246 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1451 Lines: 43 3.16.44-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Ravi Bangoria commit c21a493a2b44650707d06741601894329486f2ad upstream. Currently xmon data-breakpoint feature is broken. Whenever there is a watchpoint match occurs, hw_breakpoint_handler will be called by do_break via notifier chains mechanism. If watchpoint is registered by xmon, hw_breakpoint_handler won't find any associated perf_event and returns immediately with NOTIFY_STOP. Similarly, do_break also returns without notifying to xmon. Solve this by returning NOTIFY_DONE when hw_breakpoint_handler does not find any perf_event associated with matched watchpoint, rather than NOTIFY_STOP, which tells the core code to continue calling the other breakpoint handlers including the xmon one. Signed-off-by: Ravi Bangoria Signed-off-by: Michael Ellerman [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings --- arch/powerpc/kernel/hw_breakpoint.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/arch/powerpc/kernel/hw_breakpoint.c +++ b/arch/powerpc/kernel/hw_breakpoint.c @@ -227,8 +227,10 @@ int __kprobes hw_breakpoint_handler(stru rcu_read_lock(); bp = __get_cpu_var(bp_per_reg); - if (!bp) + if (!bp) { + rc = NOTIFY_DONE; goto out; + } info = counter_arch_bp(bp); /*