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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 5E9FBC2B9F4 for ; Tue, 22 Jun 2021 17:25:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3A74A61075 for ; Tue, 22 Jun 2021 17:25:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230330AbhFVR1S (ORCPT ); Tue, 22 Jun 2021 13:27:18 -0400 Received: from vulcan.natalenko.name ([104.207.131.136]:59534 "EHLO vulcan.natalenko.name" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230338AbhFVR1S (ORCPT ); Tue, 22 Jun 2021 13:27:18 -0400 Received: from spock.localnet (unknown [151.237.229.131]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by vulcan.natalenko.name (Postfix) with ESMTPSA id 6DAC2AF15A7; Tue, 22 Jun 2021 19:24:58 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=natalenko.name; s=dkim-20170712; t=1624382698; h=from:from: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; bh=I6C/9aHxf9JuxozRE08JBbfiMFOix1Z/vELCSKvQaeU=; b=mfDz2+ubFc1YGm5Q0b/GlcuCeKNgrIqR+hF2WTnf+YraDAkSBH77f2WLs8lqFLvMmsoa+3 1I1WZX0BcFEh0g7SU3Vi3mlz2puTPJi4fQ/7afE6srW9MRAcXxpwzYvzfI2xNBZn8tlv1r LKBwpsjLKUJADBPziqgLI6I4PBdG61M= From: Oleksandr Natalenko To: Greg KH Cc: stable@vger.kernel.org, Johannes Weiner , Peter Zijlstra Subject: Re: Backport d583d360a6 into 5.12 stable Date: Tue, 22 Jun 2021 19:24:56 +0200 Message-ID: <5661831.TEGnOE2T3c@spock> In-Reply-To: References: <11282373.oIR2C0Pl9h@spock> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org Hello. On =C3=BAter=C3=BD 22. =C4=8Dervna 2021 18:47:59 CEST Greg KH wrote: > On Tue, Jun 22, 2021 at 06:30:46PM +0200, Oleksandr Natalenko wrote: > > I'd like to nominate d583d360a6 ("psi: Fix psi state corruption when > > schedule() races with cgroup move") for 5.12 stable tree. > >=20 > > Recently, I've hit this: > >=20 > > ``` > > kernel: psi: inconsistent task state! task=3D2667:clementine cpu=3D21 > > psi_flags=3D0 clear=3D1 set=3D0 > > ``` > >=20 > > and after that PSI IO went crazy high. That seems to match the symptoms > > described in the commit message. >=20 > But this says it fixes 4117cebf1a9f ("psi: Optimize task switch inside > shared cgroups") which did not show up until 5.13-rc1, so how are you > hitting this issue? I'm not positive 4117cebf1a9f was a root cause of the race. To me it looks= =20 like 4117cebf1a9f just made an older issue more likely to be hit. Peter, Johannes, am I correct saying that it is still possible to hit a=20 corruption described in d583d360a6 on 5.12? > Did you try this patch on 5.12.y and see that it solved your problem? Yes, I've built the kernel with this patch, and so far it runs fine. It can= =20 take a while until the condition is hit though since it seems to be very=20 unlikely on 5.12. =2D-=20 Oleksandr Natalenko (post-factum)