Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752460AbdFVC2I (ORCPT ); Wed, 21 Jun 2017 22:28:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:57638 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752399AbdFVC2G (ORCPT ); Wed, 21 Jun 2017 22:28:06 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F152022B44 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=luto@kernel.org MIME-Version: 1.0 In-Reply-To: <207CCA52-C1A0-4AEF-BABF-FA6552CFB71F@gmail.com> References: <207CCA52-C1A0-4AEF-BABF-FA6552CFB71F@gmail.com> From: Andy Lutomirski Date: Wed, 21 Jun 2017 19:27:44 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v3 01/11] x86/mm: Don't reenter flush_tlb_func_common() To: Nadav Amit , Ingo Molnar Cc: Andy Lutomirski , X86 ML , LKML , Borislav Petkov , Linus Torvalds , Andrew Morton , Mel Gorman , "linux-mm@kvack.org" , Rik van Riel , Dave Hansen , Arjan van de Ven , Peter Zijlstra Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1763 Lines: 53 On Wed, Jun 21, 2017 at 4:26 PM, Nadav Amit wrote: > Andy Lutomirski wrote: > >> index 2a5e851f2035..f06239c6919f 100644 >> --- a/arch/x86/mm/tlb.c >> +++ b/arch/x86/mm/tlb.c >> @@ -208,6 +208,9 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next, >> static void flush_tlb_func_common(const struct flush_tlb_info *f, >> bool local, enum tlb_flush_reason reason) >> { >> + /* This code cannot presently handle being reentered. */ >> + VM_WARN_ON(!irqs_disabled()); >> + >> if (this_cpu_read(cpu_tlbstate.state) != TLBSTATE_OK) { >> leave_mm(smp_processor_id()); >> return; >> @@ -313,8 +316,12 @@ void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start, >> info.end = TLB_FLUSH_ALL; >> } >> >> - if (mm == this_cpu_read(cpu_tlbstate.loaded_mm)) >> + if (mm == this_cpu_read(cpu_tlbstate.loaded_mm)) { > > Perhaps you want to add: > > VM_WARN_ON(irqs_disabled()); > > here > >> + local_irq_disable(); >> flush_tlb_func_local(&info, TLB_LOCAL_MM_SHOOTDOWN); >> + local_irq_enable(); >> + } >> + >> if (cpumask_any_but(mm_cpumask(mm), cpu) < nr_cpu_ids) >> flush_tlb_others(mm_cpumask(mm), &info); >> put_cpu(); >> @@ -370,8 +377,12 @@ void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch) >> >> int cpu = get_cpu(); >> >> - if (cpumask_test_cpu(cpu, &batch->cpumask)) >> + if (cpumask_test_cpu(cpu, &batch->cpumask)) { > > and here? > Will do. What I really want is lockdep_assert_irqs_disabled() or, even better, for this to be implicit when calling local_irq_disable(). Ingo? --Andy