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 5E1AD3BCD28; Thu, 24 Sep 2026 16:17:57 +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=1790266678; cv=none; b=goGSAbkuq1L1gPUzVn2oS4JLBK1HDMdLEd2L0NCkf6VZJy+yq0XzXiAXRpQQezbXRt5Fcs2QZBXvXwj1QclQIdufWWwzHEbsS8rdS+Xj1BO+yett4bNqR5cO5JBiATKaShEe5MxeKCROEZgtmZ5IujB9tKYD7GySu4Zgn9gZS3I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790266678; c=relaxed/simple; bh=cbzDchNdWQM9hVa5y6UYRuOhOBDnr3hYLi9J7JOKN+I=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References; b=oF5VlNfI9U0H+UEhenVGRx7udRXKAni6reoUgJlnrhjQHzJSXFNrjn3PQNdYxZEttyS4a6OAiSUarOzt5slbz6alUZqhxKDV4W0jrYDOgQxnzRrNTIBiLBTUiVd6BNHm7cnsfh8pMss5Z1DBUtb6F41gzITHvfU3SHDguGw02Ns= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RZ9lK/qC; 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="RZ9lK/qC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D0F931F000FF; Thu, 24 Sep 2026 16:17:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790266677; bh=qYz1xOYVF9fEwCqg5xyOFO8RDNqr7m8sVlWc/qKZS8A=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=RZ9lK/qC8Ng0Br6hGQwxVoQufNdchyJa7t32RjduNTBYweSrar19Edg5j5LsvDTZd cCKUWsG95FHPtIMw9n2cr6yeEYSoYIVwMTCyaavluOSwbcRWMfEsCCvyabRAd8ilNk Arx5YIVuUGG1BRliP3h6v4OWbkMkcgBytG8enrGa2WfxtJCAjDjGpNdcwspsXrJVQ8 zjOS7LGx8wBVMZPXN0zMJ4qwTJsLufKZjoXaMSNM+HA4DSo/MMNT4TUxt8+u7hq184 qPy/XvQe3DM8ZhWQyQIaNS0iLwAfvwJZCEX8kOECdFSbvtcEVRembasxZiFbp4CedO kMWMZ0qUbAUeQ== Date: Thu, 24 Sep 2026 06:17:55 -1000 Message-ID: <9c8dd70b66bba55c87376f227d986945@kernel.org> From: Tejun Heo To: Wanwu Li Cc: David Vernet , Andrea Righi , Changwoo Min , sched-ext@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/3] tools/sched_ext: Fix three example scheduler bugs In-Reply-To: <20260924143659.268595-1-liwanwu@kylinos.cn> References: <20260924143659.268595-1-liwanwu@kylinos.cn> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Hello, Wanwu. On Thu, Sep 24, 2026 at 10:36:56PM +0800, Wanwu Li wrote: > - try_dispatch() trusts a pid popped from a cgroup's FIFO. If the > task migrated to another cgroup between enqueue and dispatch, it is > dispatched under the old cgroup's context, violating the core > "paired CPUs only run tasks from the same cgroup" invariant. 3/3 calls scx_bpf_task_cgroup() on a task from bpf_task_from_pid(). The kfunc only accepts the tasks passed to the current op, so the scheduler is disabled on its first dispatch: sched_ext: BPF scheduler "pair" enabled sched_ext: BPF scheduler "pair" disabled (runtime error) sched_ext: pair: called on a task not being operated on scx_bpf_task_cgroup+0x15b/0x160 bpf__sched_ext_ops_dispatch+0x47/0xa3 This means the patches were posted without being run at all. That's not acceptable. Please reproduce each bug and verify that the fix resolves it before posting. Thanks. -- tejun