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 D51A0C00145 for ; Mon, 12 Dec 2022 13:38:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232815AbiLLNii (ORCPT ); Mon, 12 Dec 2022 08:38:38 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35862 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232827AbiLLNhv (ORCPT ); Mon, 12 Dec 2022 08:37:51 -0500 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1484513F25 for ; Mon, 12 Dec 2022 05:37:31 -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 sin.source.kernel.org (Postfix) with ESMTPS id 64983CE0F7E for ; Mon, 12 Dec 2022 13:37:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 32142C433EF; Mon, 12 Dec 2022 13:37:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1670852247; bh=ebBjRuCjkG8VKsteYvp5syNs1Pd16Jch+udZidqdh/0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lMhZEVoQypAALDY0F1FswpYwPoakwWy5FjQPop46GqnavocXDa0oMDK7zWrPt+iKu MJUaTDcRaQvieZQS6Ct+Ja13bhECUWANNtWAaRDMNUdwf4ZkCVzlmLCYtCRbm1EB5G OEs4BfAJm+s/O3wGRH+8XCCN3jqHZjPZ6e2JN/Ek= 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 6.0 043/157] mm/khugepaged: fix GUP-fast interaction by sending IPI Date: Mon, 12 Dec 2022 14:16:31 +0100 Message-Id: <20221212130936.272916620@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221212130934.337225088@linuxfoundation.org> References: <20221212130934.337225088@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 [backported, no changes necessary] Signed-off-by: Jann Horn Signed-off-by: Sasha Levin --- include/asm-generic/tlb.h | 4 ++++ mm/khugepaged.c | 2 ++ mm/mmu_gather.c | 4 +--- 3 files changed, 7 insertions(+), 3 deletions(-) diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h index 492dce43236e..cab7cfebf40b 100644 --- a/include/asm-generic/tlb.h +++ b/include/asm-generic/tlb.h @@ -222,12 +222,16 @@ 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 28d8459d7aae..1155d356d3ac 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1093,6 +1093,7 @@ 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, @@ -1391,6 +1392,7 @@ static void collapse_and_free_pmd(struct mm_struct *mm, struct vm_area_struct *v lockdep_assert_held_write(&vma->anon_vma->root->rwsem); pmd = pmdp_collapse_flush(vma, addr, pmdp); + tlb_remove_table_sync_one(); mm_dec_nr_ptes(mm); page_table_check_pte_clear_range(mm, addr, pmd); pte_free(mm, pmd_pgtable(pmd)); diff --git a/mm/mmu_gather.c b/mm/mmu_gather.c index a71924bd38c0..ba7d26a291dd 100644 --- a/mm/mmu_gather.c +++ b/mm/mmu_gather.c @@ -152,7 +152,7 @@ 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 @@ -176,8 +176,6 @@ 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