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58b656177d
commite74a684680upstream. During page migration, the copy_highpage function is used to copy the page data to the target page. If the source page is a userspace page with MTE tags, the KASAN tag of the target page must have the match-all tag in order to avoid tag check faults during subsequent accesses to the page by the kernel. However, the target page may have been allocated in a number of ways, some of which will use the KASAN allocator and will therefore end up setting the KASAN tag to a non-match-all tag. Therefore, update the target page's KASAN tag to match the source page. We ended up unintentionally fixing this issue as a result of a bad merge conflict resolution between commite059853d14("arm64: mte: Fix/clarify the PG_mte_tagged semantics") and commit20794545c1("arm64: kasan: Revert "arm64: mte: reset the page tag in page->flags""), which preserved a tag reset for PG_mte_tagged pages which was considered to be unnecessary at the time. Because SW tags KASAN uses separate tag storage, update the code to only reset the tags when HW tags KASAN is enabled. Signed-off-by: Peter Collingbourne <pcc@google.com> Link: https://linux-review.googlesource.com/id/If303d8a709438d3ff5af5fd85706505830f52e0c Reported-by: "Kuan-Ying Lee (李冠穎)" <Kuan-Ying.Lee@mediatek.com> Cc: <stable@vger.kernel.org> # 6.1 Fixes:20794545c1("arm64: kasan: Revert "arm64: mte: reset the page tag in page->flags"") Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Link: https://lore.kernel.org/r/20230215050911.1433132-1-pcc@google.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
39 lines
901 B
C
39 lines
901 B
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Based on arch/arm/mm/copypage.c
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*
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* Copyright (C) 2002 Deep Blue Solutions Ltd, All Rights Reserved.
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* Copyright (C) 2012 ARM Ltd.
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*/
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#include <linux/bitops.h>
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#include <linux/mm.h>
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#include <asm/page.h>
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#include <asm/cacheflush.h>
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#include <asm/cpufeature.h>
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#include <asm/mte.h>
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void copy_highpage(struct page *to, struct page *from)
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{
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void *kto = page_address(to);
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void *kfrom = page_address(from);
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copy_page(kto, kfrom);
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if (system_supports_mte() && page_mte_tagged(from)) {
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if (kasan_hw_tags_enabled())
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page_kasan_tag_reset(to);
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mte_copy_page_tags(kto, kfrom);
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set_page_mte_tagged(to);
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}
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}
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EXPORT_SYMBOL(copy_highpage);
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void copy_user_highpage(struct page *to, struct page *from,
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unsigned long vaddr, struct vm_area_struct *vma)
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{
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copy_highpage(to, from);
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flush_dcache_page(to);
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}
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EXPORT_SYMBOL_GPL(copy_user_highpage);
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