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 4B222C677F1 for ; Thu, 19 Jan 2023 01:38:52 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D2D476B0078; Wed, 18 Jan 2023 20:38:51 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id CDD196B007B; Wed, 18 Jan 2023 20:38:51 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BA5096B007D; Wed, 18 Jan 2023 20:38:51 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id A7A2A6B0078 for ; Wed, 18 Jan 2023 20:38:51 -0500 (EST) Received: from smtpin01.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 8887CC02B9 for ; 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imf17.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf17.hostedemail.com: domain of byungchul.park@lge.com designates 156.147.23.51 as permitted sender) smtp.mailfrom=byungchul.park@lge.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1674092330; a=rsa-sha256; cv=none; b=OxiK9RUlL+O6s569g0Y3yyzcMMILZwFXV2Pt0laNsNcuqn/S0CCew6Ub8sWfVMMzM9mccP BbtmndSgtG/2DfLW7HAP0jAQUfO+hry57QWEWixSceP2/xgIUW4cNq8i7gm469tDLJLeUy FgQ9auixMD3FS6o92RLVtkntZsYVLo0= Received: from unknown (HELO lgemrelse7q.lge.com) (156.147.1.151) by 156.147.23.51 with ESMTP; 19 Jan 2023 10:38:46 +0900 X-Original-SENDERIP: 156.147.1.151 X-Original-MAILFROM: byungchul.park@lge.com Received: from unknown (HELO localhost.localdomain) (10.177.244.38) by 156.147.1.151 with ESMTP; 19 Jan 2023 10:38:46 +0900 X-Original-SENDERIP: 10.177.244.38 X-Original-MAILFROM: byungchul.park@lge.com From: Byungchul Park To: hdanton@sina.com Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, torvalds@linux-foundation.org, longman@redhat.com, penguin-kernel@I-love.SAKURA.ne.jp, max.byungchul.park@gmail.com Subject: Re: [PATCH RFC v7 08/23] dept: Apply sdt_might_sleep_strong() to PG_{locked,writeback} wait Date: Thu, 19 Jan 2023 10:38:34 +0900 Message-Id: <1674092314-16409-1-git-send-email-byungchul.park@lge.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <20230109113720.221-1-hdanton@sina.com> References: <20230109113720.221-1-hdanton@sina.com> X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: D411640004 X-Stat-Signature: w536zoxu3zkzd3kcxy69bbcom14745g8 X-HE-Tag: 1674092328-263123 X-HE-Meta: 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.007645, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Hillf wrote: > On 9 Jan 2023 12:33:36 +0900 Byungchul Park >> Makes Dept able to track dependencies by PG_{locked,writeback} waits. >> >> Signed-off-by: Byungchul Park >> --- > > Hey Byungchul +cc max.byungchul.park@gmail.com Hi, This email never reached to me. > Is DEPT able to get deadlock reported for the syzbot report [1]? DEPT can detect the case 100% *IF* the folio_trylock() is released within the same context since DEPT tracks folio_trylock(), folio_lock() and folio_unlock(), and it's definitely a deadlock. But as we know, because folio_trylock() can be released by another context like irq, it might be either just a severe slowdown of the context triggering folio_unlock() or a literal deadlock where the context is involved. I dunno which one is the case. In short, DEPT can detect this case too *IF* it's a literal deadlock, but it doesn't if it's just a slowdown. I'm planning to warn it even if there is a slowdown tho, not for now. Let me reproduce the following issue. I will share the result. > Hillf > > [1] https://lore.kernel.org/lkml/6383cde5-cf4b-facf-6e07-1378a485657d@I-love.SAKURA.ne.jp/ Byungchul