From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 02254C28E83 for ; Fri, 4 Sep 2020 11:41:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D3D002074D for ; Fri, 4 Sep 2020 11:41:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729582AbgIDLlc (ORCPT ); Fri, 4 Sep 2020 07:41:32 -0400 Received: from mx01.bbu.dsd.mx.bitdefender.com ([91.199.104.161]:49556 "EHLO mx01.bbu.dsd.mx.bitdefender.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729797AbgIDLlV (ORCPT ); Fri, 4 Sep 2020 07:41:21 -0400 Received: from smtp.bitdefender.com (smtp01.buh.bitdefender.com [10.17.80.75]) by mx01.bbu.dsd.mx.bitdefender.com (Postfix) with ESMTPS id 9B813307C934; Fri, 4 Sep 2020 14:31:07 +0300 (EEST) Received: from localhost.localdomain (unknown [195.189.155.252]) by smtp.bitdefender.com (Postfix) with ESMTPSA id D31BB3072785; Fri, 4 Sep 2020 14:31:06 +0300 (EEST) From: =?UTF-8?q?Adalbert=20Laz=C4=83r?= To: linux-mm@kvack.org Cc: linux-api@vger.kernel.org, Andrew Morton , Alexander Graf , Stefan Hajnoczi , Jerome Glisse , Paolo Bonzini , =?UTF-8?q?Mihai=20Don=C8=9Bu?= , Mircea Cirjaliu , Andy Lutomirski , Arnd Bergmann , Sargun Dhillon , Aleksa Sarai , Oleg Nesterov , Jann Horn , Kees Cook , Matthew Wilcox , Christian Brauner , =?UTF-8?q?Adalbert=20Laz=C4=83r?= Subject: [RESEND RFC PATCH 3/5] mm/mmu_notifier: remove lockdep map, allow mmu notifier to be used in nested scenarios Date: Fri, 4 Sep 2020 14:31:14 +0300 Message-Id: <20200904113116.20648-4-alazar@bitdefender.com> In-Reply-To: <20200904113116.20648-1-alazar@bitdefender.com> References: <20200904113116.20648-1-alazar@bitdefender.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-api-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org From: Mircea Cirjaliu The combination of remote mapping + KVM causes nested range invalidations, which reports lockdep warnings. Signed-off-by: Mircea Cirjaliu Signed-off-by: Adalbert Lazăr --- include/linux/mmu_notifier.h | 5 +---- mm/mmu_notifier.c | 19 ------------------- 2 files changed, 1 insertion(+), 23 deletions(-) diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h index 736f6918335e..81ea457d41be 100644 --- a/include/linux/mmu_notifier.h +++ b/include/linux/mmu_notifier.h @@ -440,12 +440,10 @@ mmu_notifier_invalidate_range_start(struct mmu_notifier_range *range) { might_sleep(); - lock_map_acquire(&__mmu_notifier_invalidate_range_start_map); if (mm_has_notifiers(range->mm)) { range->flags |= MMU_NOTIFIER_RANGE_BLOCKABLE; __mmu_notifier_invalidate_range_start(range); } - lock_map_release(&__mmu_notifier_invalidate_range_start_map); } static inline int @@ -453,12 +451,11 @@ mmu_notifier_invalidate_range_start_nonblock(struct mmu_notifier_range *range) { int ret = 0; - lock_map_acquire(&__mmu_notifier_invalidate_range_start_map); if (mm_has_notifiers(range->mm)) { range->flags &= ~MMU_NOTIFIER_RANGE_BLOCKABLE; ret = __mmu_notifier_invalidate_range_start(range); } - lock_map_release(&__mmu_notifier_invalidate_range_start_map); + return ret; } diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c index 06852b896fa6..928751bd8630 100644 --- a/mm/mmu_notifier.c +++ b/mm/mmu_notifier.c @@ -22,12 +22,6 @@ /* global SRCU for all MMs */ DEFINE_STATIC_SRCU(srcu); -#ifdef CONFIG_LOCKDEP -struct lockdep_map __mmu_notifier_invalidate_range_start_map = { - .name = "mmu_notifier_invalidate_range_start" -}; -#endif - /* * The mmu_notifier_subscriptions structure is allocated and installed in * mm->notifier_subscriptions inside the mm_take_all_locks() protected @@ -242,8 +236,6 @@ mmu_interval_read_begin(struct mmu_interval_notifier *interval_sub) * will always clear the below sleep in some reasonable time as * subscriptions->invalidate_seq is even in the idle state. */ - lock_map_acquire(&__mmu_notifier_invalidate_range_start_map); - lock_map_release(&__mmu_notifier_invalidate_range_start_map); if (is_invalidating) wait_event(subscriptions->wq, READ_ONCE(subscriptions->invalidate_seq) != seq); @@ -572,13 +564,11 @@ void __mmu_notifier_invalidate_range_end(struct mmu_notifier_range *range, struct mmu_notifier_subscriptions *subscriptions = range->mm->notifier_subscriptions; - lock_map_acquire(&__mmu_notifier_invalidate_range_start_map); if (subscriptions->has_itree) mn_itree_inv_end(subscriptions); if (!hlist_empty(&subscriptions->list)) mn_hlist_invalidate_end(subscriptions, range, only_end); - lock_map_release(&__mmu_notifier_invalidate_range_start_map); } void __mmu_notifier_invalidate_range(struct mm_struct *mm, @@ -612,13 +602,6 @@ int __mmu_notifier_register(struct mmu_notifier *subscription, lockdep_assert_held_write(&mm->mmap_sem); BUG_ON(atomic_read(&mm->mm_users) <= 0); - if (IS_ENABLED(CONFIG_LOCKDEP)) { - fs_reclaim_acquire(GFP_KERNEL); - lock_map_acquire(&__mmu_notifier_invalidate_range_start_map); - lock_map_release(&__mmu_notifier_invalidate_range_start_map); - fs_reclaim_release(GFP_KERNEL); - } - if (!mm->notifier_subscriptions) { /* * kmalloc cannot be called under mm_take_all_locks(), but we @@ -1062,8 +1045,6 @@ void mmu_interval_notifier_remove(struct mmu_interval_notifier *interval_sub) * The possible sleep on progress in the invalidation requires the * caller not hold any locks held by invalidation callbacks. */ - lock_map_acquire(&__mmu_notifier_invalidate_range_start_map); - lock_map_release(&__mmu_notifier_invalidate_range_start_map); if (seq) wait_event(subscriptions->wq, READ_ONCE(subscriptions->invalidate_seq) != seq);