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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5E0D9FF8861 for ; Mon, 27 Apr 2026 10:44:07 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C9E1F6B008C; Mon, 27 Apr 2026 06:44:06 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C4DD06B0092; Mon, 27 Apr 2026 06:44:06 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B63EF6B0093; Mon, 27 Apr 2026 06:44:06 -0400 (EDT) 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 A11E36B008C for ; Mon, 27 Apr 2026 06:44:06 -0400 (EDT) Received: from smtpin01.hostedemail.com (lb01b-stub [10.200.18.250]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 5B796C046E for ; Mon, 27 Apr 2026 10:44:06 +0000 (UTC) X-FDA: 84704000892.01.4D06EF5 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf23.hostedemail.com (Postfix) with ESMTP id C0789140002 for ; Mon, 27 Apr 2026 10:44:04 +0000 (UTC) Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=K8qaMwJC; spf=pass (imf23.hostedemail.com: domain of akpm@linux-foundation.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1777286644; 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-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=7TbutU5ZwoGRvmAgJqQ0DEtGQomyedCE5ty8Rp4BqQQ=; b=S189nDD7NW66Mnjl4FSCW5NgS+1hLDntk7RPkefB2GC1n15HRZix4YBjCso7i3tGM4hvuo 5GQeCjNzLR3ir8Q/m3obHSPo5f9uQV4lJxbXkraWZswN19lv7uy3V5r5IYTqkdgMAUUTom JYzQJDxEe3OFT200ZTf6+z86OEMIy3Q= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=K8qaMwJC; spf=pass (imf23.hostedemail.com: domain of akpm@linux-foundation.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1777286644; a=rsa-sha256; cv=none; b=FaJROpZ5tQKxmiaYkUN+IwEdcZn+LPj+/5WdtHif6phdN4jnYe2iHPVWEj9D6udyhUS616 m0E0WNx6OClbSLq/Ern8YFyXlVz0WhyJEG2l9txTud3DF1UrphMwcl0fV23twp/YV2uqrK dqNX7H2OvIUyraZ4TcfXFboxERE6LIg= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 05EC160138; Mon, 27 Apr 2026 10:44:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 500D9C2BCB4; Mon, 27 Apr 2026 10:44:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1777286643; bh=iTndbkVHwjqibIZVTSPWbo8ojcxJAy0mB2LeI5+NXD8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=K8qaMwJCaqiC/yQFukTnoCCKBEdcWHxwZ2CKVJKGiGXAeCJT49g4amyjQTrZv6yJl EeazLQ2ZXtADk4bUag8sm3blu2HWaiT8O/wPFYsFl6WlK17luWwBc2wQTEmq+YJV9v YPk4oUIeYEmjNT79i47KevFsVW5wSqODNbJm+d2k= Date: Mon, 27 Apr 2026 03:44:02 -0700 From: Andrew Morton To: Qi Zheng Cc: shakeel.butt@linux.dev, syzbot , Liam.Howlett@oracle.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, ljs@kernel.org, surenb@google.com, syzkaller-bugs@googlegroups.com, vbabka@kernel.org, Muchun Song Subject: Re: [syzbot] [mm?] WARNING: bad unlock balance in do_wp_page Message-Id: <20260427034402.096cb95de92bec15becc78bb@linux-foundation.org> In-Reply-To: References: <69edca15.170a0220.38e3f1.0000.GAE@google.com> <20260426034938.db29d74982a8eb8463f8cf3a@linux-foundation.org> <20260426105532.43768b24a42744f1b52fdff2@linux-foundation.org> <3591c663-a4a9-4c22-97cf-b58b2e7d8a41@linux.dev> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-Stat-Signature: mfrb9x7dgpsak4zbi4zo9zdkccptaqne X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: C0789140002 X-Rspam-User: X-HE-Tag: 1777286644-142948 X-HE-Meta: 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 tSSbrAoO 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, 27 Apr 2026 17:43:38 +0800 Qi Zheng wrote: >=20 > Alright, it seems I have successfully reproduced it: > (The reproducer is attached at the bottom of this email.) That's a lot of code. Thanks for doing that. Maybe there's something here we can put into selftests/ > >> > >>> However, in a production environment, this is practically impossible. > >> > >> Can you expand on this? > >> > >> sysbot isn't a production environment ;) > >=20 > > Rebinding only works when the hierarchy is completely empty. This is > > generally not the case in a production environment (e.g. when systemd > > is used). > >=20 > > BTW, it seems rebinding is about to be deprecated: > >=20 > > cgroup1_reconfigure > > --> pr_warn("option changes via remount are deprecated (pid=3D%d comm= =3D%s)\n", > > =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 task_tgid_nr(current), current->comm= ); > >=20 > > Also, it appears the current memcg subsystem assumes that > > cgroup_subsys_on_dfl(memory_cgrp_subsys) cannot be changed at runtime. > > (Please correct me if I missed anything.) > >=20 > > If we can get a reproducer, we can try the following fix, or simply drop > > rebinding altogether? We'll want something which is applicable to 7.1-rcX please. Removal of rebinding sounds like something we'd address in 7.2 or later. > > From 6ae41b91339625dd7bf0f819f775f26e78171a73 Mon Sep 17 00:00:00 2001 > > From: Qi Zheng > > Date: Mon, 27 Apr 2026 11:20:21 +0800 > > Subject: [PATCH] mm: memcontrol: fix rcu unbalance in > > =A0get_non_dying_memcg_end() > >=20 > > Signed-off-by: Qi Zheng > > --- > > =A0mm/memcontrol.c | 30 ++++++++++++++++++++---------- > > =A01 file changed, 20 insertions(+), 10 deletions(-) >=20 > With the above patch applied, the warnings are gone. >=20 > If no one objects, I'll submit the formal fix. Or should we actually > just remove rebinding instead? I suggest we just fix up current -rc please.