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=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 430E9C433E1 for ; Thu, 16 Jul 2020 22:04:41 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 9BE0E2076D for ; Thu, 16 Jul 2020 22:04:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9BE0E2076D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=i-love.sakura.ne.jp Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 0531D6B005A; Thu, 16 Jul 2020 18:04:40 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 002C76B005C; Thu, 16 Jul 2020 18:04:39 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E5C7C8D0003; Thu, 16 Jul 2020 18:04:39 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0111.hostedemail.com [216.40.44.111]) by kanga.kvack.org (Postfix) with ESMTP id CCC8B6B005A for ; Thu, 16 Jul 2020 18:04:39 -0400 (EDT) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 60078181AC9C6 for ; Thu, 16 Jul 2020 22:04:39 +0000 (UTC) X-FDA: 77045319078.22.woman79_1315da826f05 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin22.hostedemail.com (Postfix) with ESMTP id 8A5BE18038E84 for ; Thu, 16 Jul 2020 22:04:32 +0000 (UTC) X-HE-Tag: woman79_1315da826f05 X-Filterd-Recvd-Size: 2348 Received: from www262.sakura.ne.jp (www262.sakura.ne.jp [202.181.97.72]) by imf04.hostedemail.com (Postfix) with ESMTP for ; Thu, 16 Jul 2020 22:04:31 +0000 (UTC) Received: from fsav102.sakura.ne.jp (fsav102.sakura.ne.jp [27.133.134.229]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id 06GM4Llg061458; Fri, 17 Jul 2020 07:04:21 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav102.sakura.ne.jp (F-Secure/fsigk_smtp/550/fsav102.sakura.ne.jp); Fri, 17 Jul 2020 07:04:21 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/fsav102.sakura.ne.jp) Received: from [192.168.1.9] (M106072142033.v4.enabler.ne.jp [106.72.142.33]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id 06GM4GME061441 (version=TLSv1.2 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Fri, 17 Jul 2020 07:04:21 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Subject: Re: [PATCH] mm: Warn mmput() from memory reclaim context. To: David Rientjes Cc: Andrew Morton , linux-mm References: <20200716153034.4935-1-penguin-kernel@I-love.SAKURA.ne.jp> From: Tetsuo Handa Message-ID: Date: Fri, 17 Jul 2020 07:04:13 +0900 User-Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 8A5BE18038E84 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 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: On 2020/07/17 4:45, David Rientjes wrote: > I wasn't familiar with this particular report, but it seems like the fix > is simply to do the kzalloc() before taking delayed_uprobe_lock and > freeing it if delayed_uprobe_check() already finds one for that uprobe? The fix will be to use mmput_async() ( https://lkml.kernel.org/r/20200716162931.g3delsp7qmfjup6x@wittgenstein ). We didn't call mmput() from the OOM reaper context. I think the reason is that __mmput() might do something more complicated which blocks reclaiming memory.