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=-8.8 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=ham 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 632B2C433E2 for ; Wed, 9 Sep 2020 22:13:52 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C4B9F20C09 for ; Wed, 9 Sep 2020 22:13:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C4B9F20C09 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 4520D6B0037; Wed, 9 Sep 2020 18:13:51 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3DA4D6B006C; Wed, 9 Sep 2020 18:13:51 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2F0096B006E; Wed, 9 Sep 2020 18:13:51 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0073.hostedemail.com [216.40.44.73]) by kanga.kvack.org (Postfix) with ESMTP id 146146B0037 for ; Wed, 9 Sep 2020 18:13:51 -0400 (EDT) Received: from smtpin02.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id CE088180AD817 for ; Wed, 9 Sep 2020 22:13:50 +0000 (UTC) X-FDA: 77244926220.02.sleep26_34004d5270e0 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin02.hostedemail.com (Postfix) with ESMTP id A9DCE100BF44A for ; Wed, 9 Sep 2020 22:13:50 +0000 (UTC) X-HE-Tag: sleep26_34004d5270e0 X-Filterd-Recvd-Size: 2616 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf44.hostedemail.com (Postfix) with ESMTP for ; Wed, 9 Sep 2020 22:13:50 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id B20C3ACDF; Wed, 9 Sep 2020 22:14:04 +0000 (UTC) Subject: Re: [PATCH v2] mm/vmscan: fix infinite loop in drop_slab_node To: Matthew Wilcox , Chris Down Cc: zangchunxin@bytedance.com, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Muchun Song References: <20200909152047.27905-1-zangchunxin@bytedance.com> <16906d44-9e3c-76a1-f1a9-ced61e865467@suse.cz> <20200909214724.GA1577471@chrisdown.name> <20200909215209.GP6583@casper.infradead.org> From: Vlastimil Babka Message-ID: <4e022a8c-68da-a322-4101-926a0bb9d44b@suse.cz> Date: Thu, 10 Sep 2020 00:13:48 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <20200909215209.GP6583@casper.infradead.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: A9DCE100BF44A X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam02 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 9/9/20 11:52 PM, Matthew Wilcox wrote: > On Wed, Sep 09, 2020 at 10:47:24PM +0100, Chris Down wrote: >> Vlastimil Babka writes: >> > - Exit also on other signals such as SIGABRT, SIGTERM? If I write to drop_caches >> > and think it's too long, I would prefer to kill it by ctrl-c and not just kill >> >> Oh dear, fatal_signal_pending() doesn't consider cases with no more >> userspace instructions due to SIG_DFL on TERM/INT etc, that seems misleading >> :-( I had (naively) believed it internally checks the same set as >> TASK_KILLABLE. >> >> Chuxin, Muchun, can you please make it work using TASK_KILLABLE in a similar >> way to how schedule_timeout_killable and friends do it instead, so that >> other signals will be caught? > > You're mistaken. Ah actually it was me who thought fatal_signal_pending() was only for SIGKILL, OOM and whatnot. Sorry for the noise. > if (sig_fatal(p, sig) && > !(signal->flags & SIGNAL_GROUP_EXIT) && > !sigismember(&t->real_blocked, sig) && > (sig == SIGKILL || !p->ptrace)) { > ... > sigaddset(&t->pending.signal, SIGKILL); > > static inline int __fatal_signal_pending(struct task_struct *p) > { > return unlikely(sigismember(&p->pending.signal, SIGKILL)); > } >