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]) by smtp.lore.kernel.org (Postfix) with ESMTP id 51517C54EBC for ; Sun, 8 Jan 2023 23:49:36 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 92F578E0002; Sun, 8 Jan 2023 18:49:35 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 8DF9D8E0001; Sun, 8 Jan 2023 18:49:35 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7F5B28E0002; Sun, 8 Jan 2023 18:49:35 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 710028E0001 for ; Sun, 8 Jan 2023 18:49:35 -0500 (EST) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 3A73D1A0101 for ; Sun, 8 Jan 2023 23:49:35 +0000 (UTC) X-FDA: 80333276310.19.E545E9D Received: from r3-20.sinamail.sina.com.cn (r3-20.sinamail.sina.com.cn [202.108.3.20]) by imf20.hostedemail.com (Postfix) with ESMTP id 1717D1C0011 for ; Sun, 8 Jan 2023 23:49:31 +0000 (UTC) Authentication-Results: imf20.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf20.hostedemail.com: domain of hdanton@sina.com designates 202.108.3.20 as permitted sender) smtp.mailfrom=hdanton@sina.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1673221773; 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; bh=gHyhBtCUmhJjy36h3MpV8jSiNHA2u+xHrcsZB8+m8CI=; b=jMIo+tjQJeh7CSIXKmiuqDDhqRGvsaPfWrFXpb2+opx8wv1iSpWO/g/0hmtgPT+X+k+hYf KWrsmSTvo6MXPFV92BOZn9QnquaEVtGA1QlRpQid3bch4yyJIOBWYkkXQ1U3czHUbQDQ7G hUcSDFwHcIsq6iSa1I049cShzydYm2U= ARC-Authentication-Results: i=1; imf20.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf20.hostedemail.com: domain of hdanton@sina.com designates 202.108.3.20 as permitted sender) smtp.mailfrom=hdanton@sina.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1673221773; a=rsa-sha256; cv=none; b=rpoKJQs7E1R6YhcpIyezQ6wdA+ArvDaHHvLkpD1d6XbK7Ih+hHyp10EWjFd1GUkfUXxrye WRXa21GYis+ZS4DI09VXaeWa1xZYUabaSYhkkOt330R4JzcbLRWa3xPP/Xd+kIxgUg5Z/U TsinWgQz+d5K4mnt6oQuUVOkAsXY0jc= Received: from unknown (HELO localhost.localdomain)([114.249.57.238]) by sina.com (172.16.97.35) with ESMTP id 63BB55BE00037D0C; Sun, 9 Jan 2023 07:46:07 +0800 (CST) X-Sender: hdanton@sina.com X-Auth-ID: hdanton@sina.com X-SMAIL-MID: 79999315075814 From: Hillf Danton To: Munehisa Kamata Cc: hannes@cmpxchg.org, ebiggers@kernel.org, mengcc@amazon.com, surenb@google.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: another use-after-free in ep_remove_wait_queue() Date: Mon, 9 Jan 2023 07:49:17 +0800 Message-Id: <20230108234917.5322-1-hdanton@sina.com> In-Reply-To: <20230108222548.698721-1-kamatam@amazon.com> References: <20230107080702.4907-1-hdanton@sina.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 1717D1C0011 X-Rspamd-Server: rspam09 X-Rspam-User: X-Stat-Signature: f6rdp8n36xsrcs8kk7ppoepte8rpziuh X-HE-Tag: 1673221771-196047 X-HE-Meta: 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000115, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 8 Jan 2023 14:25:48 -0800 PM Munehisa Kamata wrote: > > That patch survived the repro in my original post, however, the waker > (rmdir) was getting stuck until a file descriptor of the epoll instance or > the pressure file got closed. So, if the following modified repro runs > with the patch, the waker never returns (unless the sleeper gets killed) > while holding cgroup_mutex. This doesn't seem to be what you expected to > see with the patch, does it? Even wake_up_all() does not appear to empty > the queue, but wake_up_pollfree() does. Thanks for your testing. And the debugging completes. Mind sending a patch with wake_up_pollfree() folded? Hillf