From patchwork Fri Nov 5 20:48:07 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 12605909 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1D969C433EF for ; Fri, 5 Nov 2021 20:48:10 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C669D60E94 for ; Fri, 5 Nov 2021 20:48:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org C669D60E94 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 738789400F8; Fri, 5 Nov 2021 16:48:09 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6E8B29400EF; Fri, 5 Nov 2021 16:48:09 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5D7579400F8; Fri, 5 Nov 2021 16:48:09 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0119.hostedemail.com [216.40.44.119]) by kanga.kvack.org (Postfix) with ESMTP id 4FEF79400EF for ; Fri, 5 Nov 2021 16:48:09 -0400 (EDT) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 174718249980 for ; Fri, 5 Nov 2021 20:48:09 +0000 (UTC) X-FDA: 78776063898.28.ECD78D4 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf06.hostedemail.com (Postfix) with ESMTP id BE888801A8BF for ; Fri, 5 Nov 2021 20:48:08 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id CC3A760FBF; Fri, 5 Nov 2021 20:48:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1636145288; bh=8zNn0MTxAyxMFfsR2o/RpV1VmQ5LkBRO4BH3td/iDdk=; h=Date:From:To:Subject:In-Reply-To:From; b=IYW5oQV4FQVoInok6fvQeiuXjqjkirgW+Jrb7HTCHRTkFb/9uuLPabxOX44McEj3z ObtdTdzn7mMUHRHtulxIC3XqrQ0AyO+YPggEHlkZXwtFx/en3RG4YLddPz3uQlw66v RFByHfdgSbvM93BiYZKMoY9YKRAng3XyRZpdiPn0= Date: Fri, 05 Nov 2021 13:48:07 -0700 From: Andrew Morton To: akpm@linux-foundation.org, linux-mm@kvack.org, mm-commits@vger.kernel.org, sj@kernel.org, torvalds@linux-foundation.org, xhao@linux.alibaba.com Subject: [patch 255/262] mm/damon/dbgfs: add adaptive_targets list check before enable monitor_on Message-ID: <20211105204807.WLs3d5z72%akpm@linux-foundation.org> In-Reply-To: <20211105133408.cccbb98b71a77d5e8430aba1@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: BE888801A8BF X-Stat-Signature: mw9basssfqxe9y5izk7sfo8k1uy8ji89 Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=IYW5oQV4; dmarc=none; spf=pass (imf06.hostedemail.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org X-HE-Tag: 1636145288-12279 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Xin Hao Subject: mm/damon/dbgfs: add adaptive_targets list check before enable monitor_on When the ctx->adaptive_targets list is empty, I did some test on monitor_on interface like this. # cat /sys/kernel/debug/damon/target_ids # # echo on > /sys/kernel/debug/damon/monitor_on # damon: kdamond (5390) starts Though the ctx->adaptive_targets list is empty, but the kthread_run still be called, and the kdamond.x thread still be created, this is meaningless. So there adds a judgment in 'dbgfs_monitor_on_write', if the ctx->adaptive_targets list is empty, return -EINVAL. Link: https://lkml.kernel.org/r/0a60a6e8ec9d71989e0848a4dc3311996ca3b5d4.1634720326.git.xhao@linux.alibaba.com Signed-off-by: Xin Hao Reviewed-by: SeongJae Park Signed-off-by: Andrew Morton --- include/linux/damon.h | 1 + mm/damon/core.c | 5 +++++ mm/damon/dbgfs.c | 15 ++++++++++++--- 3 files changed, 18 insertions(+), 3 deletions(-) --- a/include/linux/damon.h~mm-damon-dbgfs-add-adaptive_targets-list-check-before-enable-monitor_on +++ a/include/linux/damon.h @@ -440,6 +440,7 @@ void damon_destroy_scheme(struct damos * struct damon_target *damon_new_target(unsigned long id); void damon_add_target(struct damon_ctx *ctx, struct damon_target *t); +bool damon_targets_empty(struct damon_ctx *ctx); void damon_free_target(struct damon_target *t); void damon_destroy_target(struct damon_target *t); unsigned int damon_nr_regions(struct damon_target *t); --- a/mm/damon/core.c~mm-damon-dbgfs-add-adaptive_targets-list-check-before-enable-monitor_on +++ a/mm/damon/core.c @@ -180,6 +180,11 @@ void damon_add_target(struct damon_ctx * list_add_tail(&t->list, &ctx->adaptive_targets); } +bool damon_targets_empty(struct damon_ctx *ctx) +{ + return list_empty(&ctx->adaptive_targets); +} + static void damon_del_target(struct damon_target *t) { list_del(&t->list); --- a/mm/damon/dbgfs.c~mm-damon-dbgfs-add-adaptive_targets-list-check-before-enable-monitor_on +++ a/mm/damon/dbgfs.c @@ -878,12 +878,21 @@ static ssize_t dbgfs_monitor_on_write(st return -EINVAL; } - if (!strncmp(kbuf, "on", count)) + if (!strncmp(kbuf, "on", count)) { + int i; + + for (i = 0; i < dbgfs_nr_ctxs; i++) { + if (damon_targets_empty(dbgfs_ctxs[i])) { + kfree(kbuf); + return -EINVAL; + } + } ret = damon_start(dbgfs_ctxs, dbgfs_nr_ctxs); - else if (!strncmp(kbuf, "off", count)) + } else if (!strncmp(kbuf, "off", count)) { ret = damon_stop(dbgfs_ctxs, dbgfs_nr_ctxs); - else + } else { ret = -EINVAL; + } if (!ret) ret = count;