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 12DC9C00144 for ; Mon, 1 Aug 2022 19:06:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234731AbiHATGO (ORCPT ); Mon, 1 Aug 2022 15:06:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52704 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234480AbiHATFI (ORCPT ); Mon, 1 Aug 2022 15:05:08 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C0835422DF; Mon, 1 Aug 2022 12:03:28 -0700 (PDT) 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 ams.source.kernel.org (Postfix) with ESMTPS id C119EB81615; Mon, 1 Aug 2022 19:03:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 454CBC43142; Mon, 1 Aug 2022 19:03:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1659380605; bh=+4SKTbw3nLXOlgU1lDhCJECLQjdJh357I9ceTKF9pwQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QX8r6atMPhqcjN7IJB0k1qFfzDCjtMt49El1V0xg2N7k+dAj52lsx2d/xOS+xBrbx 84kEuj+yvIiaEg2gq8AtZadjoZt7WObXroMBrpu0U9ehbqruR/HgeE4AdHn9qiS8z+ 4r+TbIlgxoBf5fAyuux7ejCf0KsVfuUk7uN6dK/rAMIV3GarIVfk8I3IwFQ+lJSxea rxyuXoeL5BOV2wkwpHTITmnMvNgvNXxBKnyMZD4hdCcylpwYP48fXru5nnOb3NY/Ul o7UEb6XhkVd8pgbXBaF+VJlD80Qct3gJyo61madl04SHp8DLfw9OjObsp+nx5DwvlZ JdzVhkg11VBDQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Peter Zijlstra , Will Deacon , Linus Torvalds , Sasha Levin , aneesh.kumar@linux.ibm.com, npiggin@gmail.com, linux-arch@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH AUTOSEL 5.4 4/6] mmu_gather: Force tlb-flush VM_PFNMAP vmas Date: Mon, 1 Aug 2022 15:03:15 -0400 Message-Id: <20220801190317.3819520-4-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220801190317.3819520-1-sashal@kernel.org> References: <20220801190317.3819520-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Peter Zijlstra [ Upstream commit b67fbebd4cf980aecbcc750e1462128bffe8ae15 ] Jann reported a race between munmap() and unmap_mapping_range(), where unmap_mapping_range() will no-op once unmap_vmas() has unlinked the VMA; however munmap() will not yet have invalidated the TLBs. Therefore unmap_mapping_range() will complete while there are still (stale) TLB entries for the specified range. Mitigate this by force flushing TLBs for VM_PFNMAP ranges. Signed-off-by: Peter Zijlstra (Intel) Acked-by: Will Deacon Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- include/asm-generic/tlb.h | 31 ++++++++++++++++--------------- 1 file changed, 16 insertions(+), 15 deletions(-) diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h index fe05a8562c52..c44f7ac97f19 100644 --- a/include/asm-generic/tlb.h +++ b/include/asm-generic/tlb.h @@ -271,6 +271,7 @@ struct mmu_gather { */ unsigned int vma_exec : 1; unsigned int vma_huge : 1; + unsigned int vma_pfn : 1; unsigned int batch_count; @@ -345,7 +346,6 @@ tlb_update_vma_flags(struct mmu_gather *tlb, struct vm_area_struct *vma) { } #else /* CONFIG_MMU_GATHER_NO_RANGE */ #ifndef tlb_flush - /* * When an architecture does not provide its own tlb_flush() implementation * but does have a reasonably efficient flush_vma_range() implementation @@ -365,6 +365,9 @@ static inline void tlb_flush(struct mmu_gather *tlb) flush_tlb_range(&vma, tlb->start, tlb->end); } } +#endif + +#endif /* CONFIG_MMU_GATHER_NO_RANGE */ static inline void tlb_update_vma_flags(struct mmu_gather *tlb, struct vm_area_struct *vma) @@ -382,17 +385,9 @@ tlb_update_vma_flags(struct mmu_gather *tlb, struct vm_area_struct *vma) */ tlb->vma_huge = !!(vma->vm_flags & VM_HUGETLB); tlb->vma_exec = !!(vma->vm_flags & VM_EXEC); + tlb->vma_pfn = !!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)); } -#else - -static inline void -tlb_update_vma_flags(struct mmu_gather *tlb, struct vm_area_struct *vma) { } - -#endif - -#endif /* CONFIG_MMU_GATHER_NO_RANGE */ - static inline void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb) { if (!tlb->end) @@ -476,12 +471,18 @@ static inline void tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vm return; /* - * Do a TLB flush and reset the range at VMA boundaries; this avoids - * the ranges growing with the unused space between consecutive VMAs, - * but also the mmu_gather::vma_* flags from tlb_start_vma() rely on - * this. + * VM_PFNMAP is more fragile because the core mm will not track the + * page mapcount -- there might not be page-frames for these PFNs after + * all. Force flush TLBs for such ranges to avoid munmap() vs + * unmap_mapping_range() races. */ - tlb_flush_mmu_tlbonly(tlb); + if (tlb->vma_pfn || !IS_ENABLED(CONFIG_MMU_GATHER_MERGE_VMAS)) { + /* + * Do a TLB flush and reset the range at VMA boundaries; this avoids + * the ranges growing with the unused space between consecutive VMAs. + */ + tlb_flush_mmu_tlbonly(tlb); + } } /* -- 2.35.1