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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 92E87CD98C7 for ; Wed, 10 Jun 2026 01:14:36 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id BC11F6B00B3; Tue, 9 Jun 2026 21:14:32 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AA6426B00B2; Tue, 9 Jun 2026 21:14:32 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8AAE26B00B4; Tue, 9 Jun 2026 21:14:32 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 5D1DE6B00B2 for ; Tue, 9 Jun 2026 21:14:32 -0400 (EDT) Received: from smtpin08.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay02.hostedemail.com (Postfix) with ESMTP id F3D9D12085D for ; Wed, 10 Jun 2026 01:14:31 +0000 (UTC) X-FDA: 84862232742.08.937A4FD Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf25.hostedemail.com (Postfix) with ESMTP id 3E0EBA000D for ; Wed, 10 Jun 2026 01:14:30 +0000 (UTC) Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=RlHD8R2t; spf=pass (imf25.hostedemail.com: domain of sj@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=sj@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1781054070; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=Pb0n/eJX1vGIeSAU0z6olfpVOoRIiAMjbL+eNzYDAJ0=; b=8kIRTdBOrpIuhv6YIzXyNft/Z/mayv8n4Y1FX/MZgG3SeDnilye0WKcuJOv3Nz02uJsshy 7KzK86kd0QVnjkBRwQrAyjOCj2lvvPvFiOUa2zepf+fr2tbgo03Was21Se3FU/xqfT7+Kf o3rEChALSi7d/XiTMQvRDoA2C/lZ44E= ARC-Authentication-Results: i=1; imf25.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=RlHD8R2t; spf=pass (imf25.hostedemail.com: domain of sj@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=sj@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1781054070; b=i5r135XFo8FA0oQ3bCDogv6T8EIELkY8zMCU1XSDfsM8MD9UAHp/yr9sqP3j0VAzdT4buJ ZqMAEorHbiuM6bRnyCeXio5Xj0P+mM5iNAOoXbcemv0ewHqO9VrZg/VtnjkY4TBJb7xX4z MikDzwe17NJO9v6XrzkearfrOB24aIo= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 2F77E407E8; Wed, 10 Jun 2026 01:14:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9B4101F00899; Wed, 10 Jun 2026 01:14:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781054069; bh=Pb0n/eJX1vGIeSAU0z6olfpVOoRIiAMjbL+eNzYDAJ0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=RlHD8R2tmPn4c+ph6TQwiYaWFXdVRwLlvgGWj9DDOSP38PEXQP4YCZ85EF+s9T0fc kxU1mYxcmac/7lxca5ZVA92AiS8souEpHcb712bJVI6f+5/nqJaz8hSWt9rwsbOcRz xUfOlrMOaV5V8wOjJz7+hmaoHNP4gmAB3DMZGgaAsfqhSPCdbqL5x1JHEOXRhdQqvQ E3iy0LwpVWW8L5pa+YPy5yBFjW6FlhDh04HTskfayNOuRwGcFhUCvqd2k6bsgoE6rQ Bqd577ewXcupCac58o/T5bSVr1sh/pyNl3khldS7tKGQx/BZzYXvs272lgyHWPbA/P 3HqYRVid37o2A== From: SeongJae Park To: Cc: SeongJae Park , "# 6 . 14 . x" , Andrew Morton , damon@lists.linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [RFC PATCH v3 1/4] samples/damon/wsse: handle damon_start() failure Date: Tue, 9 Jun 2026 18:14:14 -0700 Message-ID: <20260610011420.3018-2-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260610011420.3018-1-sj@kernel.org> References: <20260610011420.3018-1-sj@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 3E0EBA000D X-Stat-Signature: 85iwbibn4rujqc1xtrou8ai31jze1pj5 X-Rspam-User: X-Rspamd-Server: rspam12 X-HE-Tag: 1781054070-974361 X-HE-Meta: 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 f1GYJlNr J1AXhk1OntV6BOBHjSMRtItI0yMuamlNYxYcIM+YB719h1WNaESU0XkL+yczfXoVany6stpg0Lmr2QU4oVL1Ky0tftbwwKJ9W+9W7jsWxjUauG4iO2f/XyUh2Ib59aogkzlC6DA3dAyiSISD2lwQ2czlgseaT3EyB2Og7xw6J8vDFXICBR+qp8r8RB/iMI2uetPek9YiPvF1zrGNCKD1KjScTcGmvpVfvOG8d4VlSZFt+b82aS3uHWDYKmddYJlWujAJXHSxeBubjhmZBN6ORFA+xfQ== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: damon_sample_wsse_start() callers assume it will clean up resources when it fails. And the function does the cleanup for context buildup failures. However, it is not doing the cleanup for damon_start() failure. As a result, when damon_start() fails, it leaks the memory for DAMON context. Free the context in case of the failure to fix the issues. Note that the issue can reliably be reproduced because the module calls damon_start() in the exclusive mode. For example, $ sudo damo start $ echo $$ | sudo tee /sys/module/damon_sample_wsse/parameters/target_pid $ echo Y | sudo tee /sys/module/damon_sample_wsse/parameters/enabled $ sudo cat /proc/allocinfo | grep damon_new_ctx Because the first command is running another DAMON instance, the third command fails the damon_start() call because the new DAMON instance cannot exclusively run. And without this fix, by repeating the third and the fourth commands above, we can show the memory consumption is only increasing due to the leaks. It requires the sudo permission though. The issue was discovered [1] by Sashiko. [1] https://lore.kernel.org/20260609145814.70163-1-sj@kernel.org Fixes: b757c6cfc696 ("samples/damon/wsse: start and stop DAMON as the user requests") Cc: # 6.14.x Signed-off-by: SeongJae Park --- samples/damon/wsse.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/samples/damon/wsse.c b/samples/damon/wsse.c index 799ad44439434..bbd9392ab5b36 100644 --- a/samples/damon/wsse.c +++ b/samples/damon/wsse.c @@ -87,8 +87,10 @@ static int damon_sample_wsse_start(void) target->pid = target_pidp; err = damon_start(&ctx, 1, true); - if (err) + if (err) { + damon_destroy_ctx(ctx); return err; + } repeat_call_control.data = ctx; return damon_call(ctx, &repeat_call_control); } -- 2.47.3