From mboxrd@z Thu Jan 1 00:00:00 1970 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=-3.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_HIGH,URIBL_BLOCKED, 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 ACEBFC433F5 for ; Mon, 3 Sep 2018 14:52:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 65B742086D for ; Mon, 3 Sep 2018 14:52:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="CCDl43y7" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 65B742086D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727447AbeICTNP (ORCPT ); Mon, 3 Sep 2018 15:13:15 -0400 Received: from mail.kernel.org ([198.145.29.99]:43494 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725949AbeICTNO (ORCPT ); Mon, 3 Sep 2018 15:13:14 -0400 Received: from jouet.infradead.org (unknown [179.97.41.186]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E93CE20869; Mon, 3 Sep 2018 14:52:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1535986363; bh=pALdNEIFLknNrngQgyn1PFMaxYL7zQd3f2N+BJkwLjc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CCDl43y7SSxYQ7gK1JXx8xBUHJJiuoJ92qrIsCl/ai1Q0w0uRGRPfOydlGOfAvtwe FZkhcsKkRWzuWb7cDQrMPb9hZnJnc3V5sLPrnDcblmYI0AmV746cPB8m5d4zjoKpTM ZfSIoXU+eKXpNC0lxs/WY24ZFbYI65FoTy5vpHQM= From: Arnaldo Carvalho de Melo To: Ingo Molnar Cc: Clark Williams , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Jiri Olsa , Alexander Shishkin , David Ahern , Namhyung Kim , Peter Zijlstra , Arnaldo Carvalho de Melo Subject: [PATCH 03/13] perf/hw_breakpoint: Modify breakpoint even if the new attr has disabled set Date: Mon, 3 Sep 2018 11:52:14 -0300 Message-Id: <20180903145224.12318-4-acme@kernel.org> X-Mailer: git-send-email 2.14.4 In-Reply-To: <20180903145224.12318-1-acme@kernel.org> References: <20180903145224.12318-1-acme@kernel.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jiri Olsa We need to change the breakpoint even if the attr with new fields has disabled set to true. Current code prevents following user code to change the breakpoint address: ptrace(PTRACE_POKEUSER, child, offsetof(struct user, u_debugreg[0]), addr_1) ptrace(PTRACE_POKEUSER, child, offsetof(struct user, u_debugreg[0]), addr_2) ptrace(PTRACE_POKEUSER, child, offsetof(struct user, u_debugreg[7]), dr7) The first PTRACE_POKEUSER creates the breakpoint with attr.disabled set to true: ptrace_set_breakpoint_addr(nr = 0) struct perf_event *bp = t->ptrace_bps[nr]; ptrace_register_breakpoint(..., disabled = true) ptrace_fill_bp_fields(..., disabled) register_user_hw_breakpoint So the second PTRACE_POKEUSER will be omitted: ptrace_set_breakpoint_addr(nr = 0) struct perf_event *bp = t->ptrace_bps[nr]; struct perf_event_attr attr = bp->attr; modify_user_hw_breakpoint(bp, &attr) if (!attr->disabled) modify_user_hw_breakpoint_check Reported-by: Milind Chabbi Signed-off-by: Jiri Olsa Acked-by: Frederic Weisbecker Acked-by: Oleg Nesterov Tested-by: Arnaldo Carvalho de Melo Cc: Alexander Shishkin Cc: David Ahern Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20180827091228.2878-3-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- kernel/events/hw_breakpoint.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c index b3814fce5ecb..fb229d9c7f3c 100644 --- a/kernel/events/hw_breakpoint.c +++ b/kernel/events/hw_breakpoint.c @@ -509,6 +509,8 @@ modify_user_hw_breakpoint_check(struct perf_event *bp, struct perf_event_attr *a */ int modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *attr) { + int err; + /* * modify_user_hw_breakpoint can be invoked with IRQs disabled and hence it * will not be possible to raise IPIs that invoke __perf_event_disable. @@ -520,11 +522,11 @@ int modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *att else perf_event_disable(bp); - if (!attr->disabled) { - int err = modify_user_hw_breakpoint_check(bp, attr, false); + err = modify_user_hw_breakpoint_check(bp, attr, false); + if (err) + return err; - if (err) - return err; + if (!attr->disabled) { perf_event_enable(bp); bp->attr.disabled = 0; } -- 2.14.4