From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8C10150E590; Fri, 18 Sep 2026 15:54:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789746864; cv=none; b=M1uLcoGXjJW2BjdSs4MW9bG0dOW2IvmRCu5Hs5nzaz2ghLq6yXLHTm8hKgIqawRc35YPeBj0bQkXAKusmhvd7p/584Vm9I5ai1XE8tkyUpoQpPsOERArh2yu+WvP3crK/Bb9NP+1hzLvbbVLlfX+qBCorPOcYvN0wtwukU0Azj8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789746864; c=relaxed/simple; bh=tq2aFE8qk8W08Dpe6HtCknDX8FIgl5aKryUBa5d/yBk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=f/D/Km2mYRH+HBLZSBPtsKmTDsnlHCyoyKBEvMXQ1bopNear9v6O5Gadb4PsLEN5R2GraNSyyA1YZCC9ruvEFKwTSnu1pU7yLfKbd2qDf7Pw4K+3NRJEXS1MpTcaq7vRGabwpmWPj2JEE+JVQSIDeRQ2wu5TzWVkqjyhMy8IRZo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Bm98SgwP; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Bm98SgwP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1600E1F00898; Fri, 18 Sep 2026 15:54:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789746863; bh=/tQprN3z/v5xGa72y/P3ii6p47RjByq0SxNA7vQBM6s=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Bm98SgwPfK3uLO2/YXScjJtjeowXcQvwbMslqUfZrApbWZ6VN5ucR8gy5K61M5qU3 k0xqYY0bXdMcklfFUUR46h1BEYiy7zGD9fD5mvxsRRZyCEL8sZkSIIX/JFoJ+qtANN VoV/vtUZ3LCDXL7G8ozkS8SCs2ds/Rxp5IJuhQnLIlDOaVQ1a4AjsVShpdtyjunaI+ VsrojhwOG8oGF2JN7EK36C7z61yac49pnnVRHjtfVYpGclWJBXdEFSv+81484mrQVC qSJa5LLNqFlVNSfimdux85VpHIJsu+AXuZgt4ge9I43doOPkMpxCAZGF2vRfUGcXxT JCk8JJNfIVllw== From: Sasha Levin To: Brett A C Sheffield , Greg Kroah-Hartman Cc: Sasha Levin , stable@vger.kernel.org, patches@lists.linux.dev, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, linux@roeck-us.net, shuah@kernel.org, patches@kernelci.org, lkft-triage@lists.linaro.org, pavel@nabladev.com, jonathanh@nvidia.com, f.fainelli@gmail.com, sudipm.mukherjee@gmail.com, rwarsow@gmx.de, conor@kernel.org, hargar@microsoft.com, broonie@kernel.org, achill@achill.org, sr@sladewatkins.com, Peter Schneider Subject: Re: [PATCH 6.12 0000/1102] 6.12.111-rc1 review Date: Fri, 18 Sep 2026 11:54:07 -0400 Message-ID: <20260918151140.2101477305-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <1e80f4b3-3919-4568-aabd-f0172581831d@googlemail.com> References: <20260917151539.408551884@linuxfoundation.org> <0dc35fd5-ee4c-4140-b154-78a49981ddb7@googlemail.com> <1e80f4b3-3919-4568-aabd-f0172581831d@googlemail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Fri, Sep 18, 2026 at 07:49:48AM +0200, Peter Schneider wrote: > So I have bisected this warning, and the first bad commit is > > [af5775004c9c02f37be06d2035a056b6abb1cb6c] sched/fair: Fix EEVDF entity > placement bug causing scheduling lag Thank you - a second bisect on top of a reverted tree is real work, and it was the right call. Dropped from the 6.12 queue: 6d71a9c61604 ("sched/fair: Fix EEVDF entity placement bug causing scheduling lag") > Trying to revert this from 6.12.111-rc1 however resulted in some > conflicts I was unable to resolve. There are other dependencies like: Right, which is why the three patches stacked on top of it came out at the same time: 6e3c0a4e1ad1 ("sched/fair: Fix lag clamp") 51b0e68cfa0a ("sched/eevdf: Fix rb augmented with multi fields") 9a8bc9bb4c3f ("sched/eevdf: Fix augmented max_slice") Some background on why this only bites 6.12: the WARN_ON_ONCE(!load) you hit needs 4423af84b297 ("sched/fair: optimize the PLACE_LAG when se->vlag is zero") and c70fc32f4443 ("sched/fair: Adhere to place_entity() constraints", which is a Fixes: for exactly this commit) to be shut up, and 6.12 has neither. More to the point, upstream has since reverted 6d71a9c61604 outright - 101f3498b4bd ("sched/fair: Revert 6d71a9c61604 ...") from January, which concludes the original commit "was wrong!" because avg_vruntime() already accounts for cfs_rq->curr when it is on_rq. 6.12 only ever picked it up as a dependency of the eevdf fixes above, so carrying placement math that mainline has disowned is not something we want here. -- Thanks, Sasha