From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 0DF06296BCA; Mon, 11 Aug 2025 16:51:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754931072; cv=none; b=sJjZmk9sJT7hQ+VyqEy7H/D9oYeEizRQrdKLEfYo/nnUwGWxDekcsd797KvXRh0FtqtYTW08eon1pHy/r4aecFOPRcEjz0bDfd3f+l7c1Qigu2wYBrXtqdThmVyy3FPWKD7rPePjdOm3xbtXpN0ayCqiRWWLMwAAGu5mcMqwUo0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754931072; c=relaxed/simple; bh=ELJRrye4XmgHiNxU4wdyLCtAW++9gjCj4DicN+IUdHI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=LqgOgqR98mH74PBdEdjJ6rmJD7bqOs7UBuPMOTjF+xTNl16p7Til8mjmYTvBo8jMzbHGVZZdFpaqdF0Skcem7Ra9TjZ0MClbrG3DKcwoR/xjjG4S1arsNwWamH05PcnBaVXfqLUlTSRmL7jr4ZhHPwqU5GXqMn92Z2nunEjhtTs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XRoRTh2u; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="XRoRTh2u" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7449CC4CEED; Mon, 11 Aug 2025 16:51:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754931071; bh=ELJRrye4XmgHiNxU4wdyLCtAW++9gjCj4DicN+IUdHI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=XRoRTh2u3XlEzucP7N1P+L5fIhmGFEFZwrCD9rBJ/dc5dOsyTttK1hxfyg3otDQSJ xEMbsUy9UGhhNU2sXV4LpRBh5mTUq856ZFHK+bx8m/auXo7IcqrOCtkay2rb2pbTff aR5+7ydCpQzfkZ/aDW9u7VFYmIoNdvrncY5VsDA3LmBFXT+0ohhNJb8ug/HzxF5qDR bR2+VAthnOSQSHP/uNdahZ8x3VOj7Z8T2j6KgzvpJs6eQwMnFwr72n9n1zRTElWhyF FJLEYYojLgcevZB8BzpAxOOho1pXiV0wnNY1NcLZgzwcTRcvagRsUZd2RSOo+2v7GW WjITrjErVqbzw== Date: Mon, 11 Aug 2025 06:51:10 -1000 From: Tejun Heo To: Jake Hillion Cc: Andrea Righi , Christian Loehle , void@manifault.com, linux-kernel@vger.kernel.org, sched-ext@lists.linux.dev, changwoo@igalia.com, hodgesd@meta.com, mingo@redhat.com, peterz@infradead.org Subject: Re: [PATCH v3 3/3] sched_ext: Guarantee rq lock on scx_bpf_cpu_rq() Message-ID: References: <20250805111036.130121-1-christian.loehle@arm.com> <20250805111036.130121-4-christian.loehle@arm.com> Precedence: bulk X-Mailing-List: sched-ext@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Mon, Aug 11, 2025 at 03:35:05PM +0100, Jake Hillion wrote: > On Sun, Aug 10, 2025 at 12:52:53PM +0200, Andrea Righi wrote: > > Yeah, this is not nice, but they would be still broken though, in PATCH 1/3 > > we force schedulers to check for NULL and, if they don't, the verifier > > won't be happy, so this already breaks existing binaries. > > I ran some testing on the sched_ext for-next branch, and scx_cosmos is > breaking in cosmos_init including the latest changes. I believe it kicks > off a timer in init, which indirectly calls > `scx_bpf_cpu_rq(cpu)->curr->flags & PF_IDLE`. This should be NULL > checked, but old binaries breaking is pretty inconvenient for new users. > > As Andrea says, this is the already merged patch triggering this. Lemme revert that. I don't think we should introduce breaking changes without grace period. Thanks. -- tejun