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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8B5E3C4708C for ; Tue, 6 Dec 2022 17:16:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235665AbiLFRQh (ORCPT ); Tue, 6 Dec 2022 12:16:37 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51718 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235314AbiLFRQc (ORCPT ); Tue, 6 Dec 2022 12:16:32 -0500 Received: from mail-wm1-x331.google.com (mail-wm1-x331.google.com [IPv6:2a00:1450:4864:20::331]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 813AB24978 for ; Tue, 6 Dec 2022 09:16:31 -0800 (PST) Received: by mail-wm1-x331.google.com with SMTP id f13-20020a1cc90d000000b003d08c4cf679so9332175wmb.5 for ; Tue, 06 Dec 2022 09:16:31 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:to:from:from:to:cc:subject:date:message-id :reply-to; bh=6TKRQpLBbl1MGS/8eSZQiqQDxHNKyQAv3DLFbOPR0iI=; b=tRzFpWsOXcSvIeeUsuNQVhH4TPPSrIPUUMR+nR1lxECdtsLXWXaBLO5SgI98f1Lw9X OjrqStjNALRUVO4RSaNbIAaiHQEH4xfu8qYaXM/XZVJisQfa5S0PakJZEJ9ncDOy5Z5I 61n8wFHOUYphUXptoubh3FaXsIcOzVqXKsgg8V9BYrZcxS8VaguIxlFPXDsTPm9bUJp3 5cFmeScd1hf8Ln9uaY81bAzabZFP2i3+vaJWL8Mz9YZJHR2iqRyD3F8+HkpBEcJty6qP iTgWIZKwdX8usydNwmJ5mSuc56OBFYCL+Q34vGgquR0+e3vLDmWcLyYLOqjdd1TkaEox E6sw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=6TKRQpLBbl1MGS/8eSZQiqQDxHNKyQAv3DLFbOPR0iI=; b=OoLAPr6Kl+5Pv+xjfomabVA6x9bTwnc9BBEmT9cwvpBwBafJSFE+NpORhRevYB9kzk EmZOLkNR1CjIeqhSSNs9XNEIQfV0o/wfrdOCVU/MDtPFeNzGc9dmtqgq9+X0hfG/nr6b vuhRrrex9tFfWkgM4q60B/Q2HtkN/jpewcVnuQLdxriGJcRDJC2aSPpsAiF4y0Sjti+l cNu8GPgWJvdGh/lOn9OX/bcdEmehvkVAcNIfQ+UkBA5T+QIqpBDhb+mGANZpxNYvBgLc y9GxAM7Ajj4LaKj3NtftcHnmle/64YhLHJhMM0gOQr1s6Tz+sPfWROZ33iB+1pqWGmyP 3bCA== X-Gm-Message-State: ANoB5pk8KrwK6basJy0yWrx868yPjKJ9uOy5Lsy2wsaa7kJKJ8onoXz6 mR0ZmS+6rKLS8eOSdDVV6iKdnvZdUBVdgyBr X-Google-Smtp-Source: AA0mqf6wPAq/GvNsXFKWyEIsNIE1jCwwperXf6xDUDusSfkAcHB4wvy/j0/hClxUtx/ywc+I9UxruQ== X-Received: by 2002:a05:600c:3543:b0:3cf:a6e8:b59b with SMTP id i3-20020a05600c354300b003cfa6e8b59bmr67154895wmq.128.1670346990049; Tue, 06 Dec 2022 09:16:30 -0800 (PST) Received: from localhost ([2a00:79e0:9d:4:d775:c942:f0bf:947f]) by smtp.gmail.com with ESMTPSA id b13-20020a05600c4e0d00b003d01b84e9b2sm9635403wmq.27.2022.12.06.09.16.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 06 Dec 2022 09:16:29 -0800 (PST) From: Jann Horn To: stable@vger.kernel.org Subject: [PATCH stable 5.10,5.15 2/3] mm/khugepaged: fix GUP-fast interaction by sending IPI Date: Tue, 6 Dec 2022 18:16:04 +0100 Message-Id: <20221206171614.1183048-3-jannh@google.com> X-Mailer: git-send-email 2.39.0.rc0.267.gcb52ba06e7-goog In-Reply-To: <20221206171614.1183048-1-jannh@google.com> References: <20221206171614.1183048-1-jannh@google.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org commit 2ba99c5e08812494bc57f319fb562f527d9bacd8 upstream. Since commit 70cbc3cc78a99 ("mm: gup: fix the fast GUP race against THP collapse"), the lockless_pages_from_mm() fastpath rechecks the pmd_t to ensure that the page table was not removed by khugepaged in between. However, lockless_pages_from_mm() still requires that the page table is not concurrently freed. Fix it by sending IPIs (if the architecture uses semi-RCU-style page table freeing) before freeing/reusing page tables. Link: https://lkml.kernel.org/r/20221129154730.2274278-2-jannh@google.com Link: https://lkml.kernel.org/r/20221128180252.1684965-2-jannh@google.com Link: https://lkml.kernel.org/r/20221125213714.4115729-2-jannh@google.com Fixes: ba76149f47d8 ("thp: khugepaged") Signed-off-by: Jann Horn Reviewed-by: Yang Shi Acked-by: David Hildenbrand Cc: John Hubbard Cc: Peter Xu Cc: Signed-off-by: Andrew Morton [manual backport: two of the three places in khugepaged that can free ptes were refactored into a common helper between 5.15 and 6.0] Signed-off-by: Jann Horn --- include/asm-generic/tlb.h | 4 ++++ mm/khugepaged.c | 3 +++ mm/mmu_gather.c | 4 +--- 3 files changed, 8 insertions(+), 3 deletions(-) diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h index 71942a1c642d..c99710b3027a 100644 --- a/include/asm-generic/tlb.h +++ b/include/asm-generic/tlb.h @@ -207,12 +207,16 @@ extern void tlb_remove_table(struct mmu_gather *tlb, void *table); #define tlb_needs_table_invalidate() (true) #endif +void tlb_remove_table_sync_one(void); + #else #ifdef tlb_needs_table_invalidate #error tlb_needs_table_invalidate() requires MMU_GATHER_RCU_TABLE_FREE #endif +static inline void tlb_remove_table_sync_one(void) { } + #endif /* CONFIG_MMU_GATHER_RCU_TABLE_FREE */ diff --git a/mm/khugepaged.c b/mm/khugepaged.c index fc02de08e912..1735123e462a 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1156,6 +1156,7 @@ static void collapse_huge_page(struct mm_struct *mm, _pmd = pmdp_collapse_flush(vma, address, pmd); spin_unlock(pmd_ptl); mmu_notifier_invalidate_range_end(&range); + tlb_remove_table_sync_one(); spin_lock(pte_ptl); isolated = __collapse_huge_page_isolate(vma, address, pte, @@ -1537,6 +1538,7 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr) /* step 4: collapse pmd */ _pmd = pmdp_collapse_flush(vma, haddr, pmd); mm_dec_nr_ptes(mm); + tlb_remove_table_sync_one(); pte_free(mm, pmd_pgtable(_pmd)); i_mmap_unlock_write(vma->vm_file->f_mapping); @@ -1623,6 +1625,7 @@ static void retract_page_tables(struct address_space *mapping, pgoff_t pgoff) /* assume page table is clear */ _pmd = pmdp_collapse_flush(vma, addr, pmd); mm_dec_nr_ptes(mm); + tlb_remove_table_sync_one(); pte_free(mm, pmd_pgtable(_pmd)); } mmap_write_unlock(mm); diff --git a/mm/mmu_gather.c b/mm/mmu_gather.c index 1b9837419bf9..8be26c7ddb47 100644 --- a/mm/mmu_gather.c +++ b/mm/mmu_gather.c @@ -139,7 +139,7 @@ static void tlb_remove_table_smp_sync(void *arg) /* Simply deliver the interrupt */ } -static void tlb_remove_table_sync_one(void) +void tlb_remove_table_sync_one(void) { /* * This isn't an RCU grace period and hence the page-tables cannot be @@ -163,8 +163,6 @@ static void tlb_remove_table_free(struct mmu_table_batch *batch) #else /* !CONFIG_MMU_GATHER_RCU_TABLE_FREE */ -static void tlb_remove_table_sync_one(void) { } - static void tlb_remove_table_free(struct mmu_table_batch *batch) { __tlb_remove_table_free(batch); -- 2.39.0.rc0.267.gcb52ba06e7-goog