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 A802AC4332F for ; Mon, 12 Dec 2022 13:15:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232549AbiLLNPa (ORCPT ); Mon, 12 Dec 2022 08:15:30 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39898 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232542AbiLLNPD (ORCPT ); Mon, 12 Dec 2022 08:15:03 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5FC79E55 for ; Mon, 12 Dec 2022 05:14:47 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id ED97761049 for ; Mon, 12 Dec 2022 13:14:46 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A214AC433D2; Mon, 12 Dec 2022 13:14:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1670850886; bh=rPkpmpKSrPDhSzBs+9f3s6K33CJm9kp4omR2ltRWXAo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Fzhd9KVvNgO0vH4Q4IDZyHqYu/N7m4N3UiQAaEKoh4x3tyaftCBw3N8xfeMNEofs2 ShARmkJmVTbfERBQYO3CIJULYnR4xgbXNwv9V/q4UIkXOeNhvz70PES0wXroScwsxB OGXPXlGttHSxhZzOl8uH3LMcrGIfK7hAl5R28y/8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jann Horn , Yang Shi , David Hildenbrand , John Hubbard , Peter Xu , Andrew Morton , Sasha Levin Subject: [PATCH 5.10 028/106] mm/khugepaged: fix GUP-fast interaction by sending IPI Date: Mon, 12 Dec 2022 14:09:31 +0100 Message-Id: <20221212130926.084585040@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221212130924.863767275@linuxfoundation.org> References: <20221212130924.863767275@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jann Horn 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 Signed-off-by: Sasha Levin --- 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 a0c4b99d2899..f40c9534f20b 100644 --- a/include/asm-generic/tlb.h +++ b/include/asm-generic/tlb.h @@ -205,12 +205,16 @@ 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 014e8b259313..0268b549bd60 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1154,6 +1154,7 @@ 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, @@ -1538,6 +1539,7 @@ 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); @@ -1625,6 +1627,7 @@ 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 03c33c93a582..205fdbb5792a 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); -- 2.35.1