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 4D589C433EF for ; Wed, 30 Mar 2022 21:44:56 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B577B6B0072; Wed, 30 Mar 2022 17:44:55 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id ADFF36B0073; Wed, 30 Mar 2022 17:44:55 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 980518D0001; Wed, 30 Mar 2022 17:44:55 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0140.hostedemail.com [216.40.44.140]) by kanga.kvack.org (Postfix) with ESMTP id 847066B0072 for ; Wed, 30 Mar 2022 17:44:55 -0400 (EDT) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 40E8F8249980 for ; Wed, 30 Mar 2022 21:44:55 +0000 (UTC) X-FDA: 79302382950.23.CB842B2 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf09.hostedemail.com (Postfix) with ESMTP id AECC114000B for ; Wed, 30 Mar 2022 21:44:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=FsXi28gMtdis5Jj9MbJiJRd8qiKWr77s/dYvW4iZVqk=; b=q35vE6HTTuQyDeuJqYmhWGFFwg Phr1RusYnMeu0U+3q9/lKXn6Rae9tnFweCN8ukLPPeBZNLB8y2ueWKJdzkf2jnbxwoWmWS1yxLaun BhIYgMyqbTzimrYjQlwERtWN3rjkD8a14giTqDBsM5kcDZT3++w03cBQR+rK3a1/58HsyLohMPZh6 eeLv7S5od/pXrK2dG3ppEaxtLrirSAmW2jq03JyVZP3vzt8KI+k3AWqd9A/QzING4Rq9pvtJZTGCg duM7Wmy+uGcrwa35k/DOBFddN20jCmK33+giroIxzUnhd+o9YDrCQZI5fNGN+9pOsJX2gjc/Krmj+ GANjxN6Q==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nZg7W-001bGh-4j; Wed, 30 Mar 2022 21:44:50 +0000 Date: Wed, 30 Mar 2022 22:44:50 +0100 From: Matthew Wilcox To: Hugh Dickins Cc: Johannes Weiner , Muchun Song , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: WARNING: mm/workingset.c:567 shadow_lru_isolate Message-ID: References: <55db706b-9bce-b820-7d88-6392374cd4fc@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <55db706b-9bce-b820-7d88-6392374cd4fc@google.com> X-Rspamd-Server: rspam09 X-Rspam-User: X-Stat-Signature: rsqtrysstubf38m7wx3ys8fpiyhp8ogh Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=q35vE6HT; dmarc=none; spf=none (imf09.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org X-Rspamd-Queue-Id: AECC114000B X-HE-Tag: 1648676694-437006 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 Mon, Mar 28, 2022 at 09:24:00PM -0700, Hugh Dickins wrote: > I'm not familiar with workingset.c, I'll make no guesses, over to you! I haven't been able to reproduce it, but I applied Feynman's Problem Solving Algorithm, and I think this will do the trick: diff --git a/lib/xarray.c b/lib/xarray.c index b95e92598b9c..d3b168f619b1 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -1079,6 +1079,7 @@ void xas_split(struct xa_state *xas, void *entry, unsigned int order) xa_mk_node(child)); if (xa_is_value(curr)) values--; + xas_update(xas, child); } else { unsigned int canon = offset - xas->xa_sibs; @@ -1093,6 +1094,7 @@ void xas_split(struct xa_state *xas, void *entry, unsigned int order) } while (offset-- > xas->xa_offset); node->nr_values += values; + xas_update(xas, node); } EXPORT_SYMBOL_GPL(xas_split); #endif (the key insight is that the update function should have removed the node from the list; the WARN_ON really means "this node should not be on the list", so there's somewhere that we're forgetting to call xas_update(), or somewhere that we're forgetting to call mapping_set_update(). I didn't find any of the latter, but I did find one of the former)