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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D5267C4332F for ; Wed, 29 Dec 2021 13:10:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239600AbhL2NKl (ORCPT ); Wed, 29 Dec 2021 08:10:41 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45142 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239363AbhL2NKg (ORCPT ); Wed, 29 Dec 2021 08:10:36 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CD32EC061574 for ; Wed, 29 Dec 2021 05:10:35 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 88DA1B81903 for ; Wed, 29 Dec 2021 13:10:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EC33AC36AE7; Wed, 29 Dec 2021 13:10:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1640783433; bh=VQ2B0wuDXmafjk9e5koIOksR1NIA/USY11VBWynEVR8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ISW9lcpSNaDv/3bwMyPO1VeTwaF+UMTxb6hwMRvRmELcy4CerL62kExmERH12vaP1 m1IxgP3ZCiLxmQ3DLNRhYe3Dtf4pQcZhS2boyvENsX2Xr+2dDaMiRbzwtaUZ38BhdM gBiJ/FjQ4/CoME6iX5CU7zVg2PeYNCig3CnNfJ7k1tFBMp7D9iMl+e5SA2fzeBJeOE MnW7XzTwQU2nTv40sAIQtSlmG9BzzS0y9jTF/WxkbdEKvMp9wjGD2i2yXqflZMt33H wMhHs77LYPeVx4ONh2pwINhUJ+34FPaSws6noxeeM6V4nYvw3WXDZFEzXCoNwxx4K0 fwThJsPGpMW2g== From: SeongJae Park To: akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, SeongJae Park Subject: [PATCH 4/4] mm/damon: Hide kernel pointer from tracepoint event Date: Wed, 29 Dec 2021 13:10:16 +0000 Message-Id: <20211229131016.23641-5-sj@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20211229131016.23641-1-sj@kernel.org> References: <20211229131016.23641-1-sj@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org DAMON's virtual address spaces monitoring primitive uses 'struct pid *' of the target process as its monitoring target id. The kernel address is exposed as-is to the user space via the DAMON tracepoint, 'damon_aggregated'. Though primarily only privileged users are allowed to access that, it would be better to avoid unnecessarily exposing kernel pointers so. Because the trace result is only required to be able to distinguish each target, we aren't need to use the pointer as-is. This commit makes the tracepoint to use the index of the target in the context's targets list as its id in the tracepoint, to hide the kernel space address. Signed-off-by: SeongJae Park --- include/trace/events/damon.h | 8 ++++---- mm/damon/core.c | 4 +++- 2 files changed, 7 insertions(+), 5 deletions(-) diff --git a/include/trace/events/damon.h b/include/trace/events/damon.h index 99ffa601e351..c79f1d4c39af 100644 --- a/include/trace/events/damon.h +++ b/include/trace/events/damon.h @@ -11,10 +11,10 @@ TRACE_EVENT(damon_aggregated, - TP_PROTO(struct damon_target *t, struct damon_region *r, - unsigned int nr_regions), + TP_PROTO(struct damon_target *t, unsigned int target_id, + struct damon_region *r, unsigned int nr_regions), - TP_ARGS(t, r, nr_regions), + TP_ARGS(t, target_id, r, nr_regions), TP_STRUCT__entry( __field(unsigned long, target_id) @@ -26,7 +26,7 @@ TRACE_EVENT(damon_aggregated, ), TP_fast_assign( - __entry->target_id = t->id; + __entry->target_id = target_id; __entry->nr_regions = nr_regions; __entry->start = r->ar.start; __entry->end = r->ar.end; diff --git a/mm/damon/core.c b/mm/damon/core.c index 6482d510dcbe..1dd153c31c9e 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -514,15 +514,17 @@ static bool kdamond_aggregate_interval_passed(struct damon_ctx *ctx) static void kdamond_reset_aggregated(struct damon_ctx *c) { struct damon_target *t; + unsigned int ti = 0; /* target's index */ damon_for_each_target(t, c) { struct damon_region *r; damon_for_each_region(r, t) { - trace_damon_aggregated(t, r, damon_nr_regions(t)); + trace_damon_aggregated(t, ti, r, damon_nr_regions(t)); r->last_nr_accesses = r->nr_accesses; r->nr_accesses = 0; } + ti++; } } -- 2.17.1