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[23.128.96.18]) by mx.google.com with ESMTP id oq12si835493ejb.443.2020.05.13.17.54.55; Wed, 13 May 2020 17:55:18 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=fWXbc6mj; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731478AbgENAvY (ORCPT + 99 others); Wed, 13 May 2020 20:51:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:56952 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729581AbgENAvY (ORCPT ); Wed, 13 May 2020 20:51:24 -0400 Received: from mail-wr1-f46.google.com (mail-wr1-f46.google.com [209.85.221.46]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E87832065D for ; Thu, 14 May 2020 00:51:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589417484; bh=49N3tnGzYfynuhivy6pFC5ffxFQNIVTg7hv5pYpj+EU=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=fWXbc6mjAB1ZwEMpb9Dfq5aEYcQArbyd4kz4PqVvgC88emogqx0HkKzDLJzMgbQYU dGt/opfj6F+eQBifN41GKWvB2O3/ojuqCJ8Wy8NzT5XqSpVzQmVnT8Vv6aXsQISyPG wBcvZex31mYm/tQ9mLGmvBedhAASxNKVlCuHBCuI= Received: by mail-wr1-f46.google.com with SMTP id 50so1684758wrc.11 for ; Wed, 13 May 2020 17:51:23 -0700 (PDT) X-Gm-Message-State: AOAM530vrVjprKJtBtp+O8IkYKHpjayBQk04MBglySzigexjXuImTsH6 zbQY9XHxZvzhRZC25V01t9JAIPWiI0uiNynz1YKpVA== X-Received: by 2002:adf:a298:: with SMTP id s24mr2213634wra.184.1589417482134; Wed, 13 May 2020 17:51:22 -0700 (PDT) MIME-Version: 1.0 References: <20200505134354.774943181@linutronix.de> <20200505134904.457578656@linutronix.de> <874ksm7n5d.fsf@nanos.tec.linutronix.de> <87o8qu5n5l.fsf@nanos.tec.linutronix.de> <875zd15c98.fsf@nanos.tec.linutronix.de> In-Reply-To: <875zd15c98.fsf@nanos.tec.linutronix.de> From: Andy Lutomirski Date: Wed, 13 May 2020 17:51:10 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [patch V6 part 3 12/29] x86/entry/common: Provide idtentry_enter/exit() To: Thomas Gleixner Cc: Andy Lutomirski , LKML , X86 ML , "Paul E. McKenney" , Alexandre Chartre , Frederic Weisbecker , Paolo Bonzini , Sean Christopherson , Masami Hiramatsu , Petr Mladek , Steven Rostedt , Joel Fernandes , Boris Ostrovsky , Juergen Gross , Brian Gerst , Mathieu Desnoyers , Josh Poimboeuf , Will Deacon Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 12, 2020 at 9:50 AM Thomas Gleixner wrote: > > Thomas Gleixner writes: > > Andy Lutomirski writes: > >> WARN_ON_ONCE(!on_thread_stack() && (regs->flags & X86_FLAGS_IF) && > >> preempt_count() == 0); > >> > >> IOW, the actual condition we want is that, if the idtenter_entry/exit > >> code might schedule or if a cond_local_irq_enable() path might > >> schedule, we had better be on the correct stack. > >> > >> Sorry for causing confusion. > > > > Nothing to be sorry about. I could have thought about it myself :) > > Let me try again. > > Move it into the actual preemption condition. Most natural place. Nice! This way the logic is clear and the warning will fire even if no actual preemption occurs. Acked-by: Andy Lutomirski