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 41F07C433EF for ; Mon, 28 Feb 2022 00:47:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230451AbiB1Arn (ORCPT ); Sun, 27 Feb 2022 19:47:43 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44282 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229662AbiB1Arn (ORCPT ); Sun, 27 Feb 2022 19:47:43 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 22EFB527C7; Sun, 27 Feb 2022 16:47:06 -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 99D78611FC; Mon, 28 Feb 2022 00:47:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id ECF8EC340E9; Mon, 28 Feb 2022 00:47:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1646009225; bh=yvVWOgpv9Go/oYD50xfImWY4+xc4po0fnGJQJsLbLWM=; h=Date:To:From:Subject:From; b=YcDGw71fSMIZvB9P9gJokzuux86H6mRiudlLQEWN7dVjArFCjy7lGlUCFC0ROkTwi bkhwOFycIndGMWPVcuhxRpwGm1uyCU4nEugWoe6xzqmcShkFStch2MnlqjEUWB+hJx TfsY9ggktTEl6YwBwgrtd+AJzyvrfiEeI62h9zoU= Date: Sun, 27 Feb 2022 16:47:04 -0800 To: mm-commits@vger.kernel.org, stable@vger.kernel.org, mike.kravetz@oracle.com, almasrymina@google.com, aneesh.kumar@linux.ibm.com, akpm@linux-foundation.org From: Andrew Morton Subject: [merged] mm-hugetlb-fix-kernel-crash-with-hugetlb-mremap.patch removed from -mm tree Message-Id: <20220228004704.ECF8EC340E9@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm/hugetlb: fix kernel crash with hugetlb mremap has been removed from the -mm tree. Its filename was mm-hugetlb-fix-kernel-crash-with-hugetlb-mremap.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: "Aneesh Kumar K.V" Subject: mm/hugetlb: fix kernel crash with hugetlb mremap This fixes the below crash: kernel BUG at include/linux/mm.h:2373! cpu 0x5d: Vector: 700 (Program Check) at [c00000003c6e76e0] pc: c000000000581a54: pmd_to_page+0x54/0x80 lr: c00000000058d184: move_hugetlb_page_tables+0x4e4/0x5b0 sp: c00000003c6e7980 msr: 9000000000029033 current = 0xc00000003bd8d980 paca = 0xc000200fff610100 irqmask: 0x03 irq_happened: 0x01 pid = 9349, comm = hugepage-mremap kernel BUG at include/linux/mm.h:2373! [link register ] c00000000058d184 move_hugetlb_page_tables+0x4e4/0x5b0 [c00000003c6e7980] c00000000058cecc move_hugetlb_page_tables+0x22c/0x5b0 (unreliable) [c00000003c6e7a90] c00000000053b78c move_page_tables+0xdbc/0x1010 [c00000003c6e7bd0] c00000000053bc34 move_vma+0x254/0x5f0 [c00000003c6e7c90] c00000000053c790 sys_mremap+0x7c0/0x900 [c00000003c6e7db0] c00000000002c450 system_call_exception+0x160/0x2c0 the kernel can't use huge_pte_offset before it set the pte entry because a page table lookup check for huge PTE bit in the page table to differentiate between a huge pte entry and a pointer to pte page. A huge_pte_alloc won't mark the page table entry huge and hence kernel should not use huge_pte_offset after a huge_pte_alloc. Link: https://lkml.kernel.org/r/20220211063221.99293-1-aneesh.kumar@linux.ibm.com Fixes: 550a7d60bd5e ("mm, hugepages: add mremap() support for hugepage backed vma") Signed-off-by: Aneesh Kumar K.V Reviewed-by: Mike Kravetz Reviewed-by: Mina Almasry Cc: Signed-off-by: Andrew Morton --- mm/hugetlb.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) --- a/mm/hugetlb.c~mm-hugetlb-fix-kernel-crash-with-hugetlb-mremap +++ a/mm/hugetlb.c @@ -4851,14 +4851,13 @@ again: } static void move_huge_pte(struct vm_area_struct *vma, unsigned long old_addr, - unsigned long new_addr, pte_t *src_pte) + unsigned long new_addr, pte_t *src_pte, pte_t *dst_pte) { struct hstate *h = hstate_vma(vma); struct mm_struct *mm = vma->vm_mm; - pte_t *dst_pte, pte; spinlock_t *src_ptl, *dst_ptl; + pte_t pte; - dst_pte = huge_pte_offset(mm, new_addr, huge_page_size(h)); dst_ptl = huge_pte_lock(h, mm, dst_pte); src_ptl = huge_pte_lockptr(h, mm, src_pte); @@ -4917,7 +4916,7 @@ int move_hugetlb_page_tables(struct vm_a if (!dst_pte) break; - move_huge_pte(vma, old_addr, new_addr, src_pte); + move_huge_pte(vma, old_addr, new_addr, src_pte, dst_pte); } flush_tlb_range(vma, old_end - len, old_end); mmu_notifier_invalidate_range_end(&range); _ Patches currently in -mm which might be from aneesh.kumar@linux.ibm.com are selftest-vm-fix-map_fixed_noreplace-test-failure.patch