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b98c94eed4
The arm64 copy_highpage() assumes that the destination page is newly
allocated and not MTE-tagged (PG_mte_tagged unset) and warns
accordingly. However, following commit 060913999d ("mm: migrate:
support poisoned recover from migrate folio"), folio_mc_copy() is called
before __folio_migrate_mapping(). If the latter fails (-EAGAIN), the
copy will be done again to the same destination page. Since
copy_highpage() already set the PG_mte_tagged flag, this second copy
will warn.
Replace the WARN_ON_ONCE(page already tagged) in the arm64
copy_highpage() with a comment.
Reported-by: syzbot+d1974fc28545a3e6218b@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/68dda1ae.a00a0220.102ee.0065.GAE@google.com
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: stable@vger.kernel.org # 6.12.x
Reviewed-by: Yang Shi <yang@os.amperecomputing.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
75 lines
1.8 KiB
C
75 lines
1.8 KiB
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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struct folio *src = page_folio(from);
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struct folio *dst = page_folio(to);
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unsigned int i, nr_pages;
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copy_page(kto, kfrom);
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if (kasan_hw_tags_enabled())
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page_kasan_tag_reset(to);
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if (!system_supports_mte())
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return;
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if (folio_test_hugetlb(src)) {
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if (!folio_test_hugetlb_mte_tagged(src) ||
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from != folio_page(src, 0))
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return;
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folio_try_hugetlb_mte_tagging(dst);
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/*
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* Populate tags for all subpages.
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*
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* Don't assume the first page is head page since
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* huge page copy may start from any subpage.
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*/
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nr_pages = folio_nr_pages(src);
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for (i = 0; i < nr_pages; i++) {
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kfrom = page_address(folio_page(src, i));
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kto = page_address(folio_page(dst, i));
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mte_copy_page_tags(kto, kfrom);
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}
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folio_set_hugetlb_mte_tagged(dst);
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} else if (page_mte_tagged(from)) {
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/*
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* Most of the time it's a new page that shouldn't have been
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* tagged yet. However, folio migration can end up reusing the
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* same page without untagging it. Ignore the warning if the
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* page is already tagged.
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*/
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try_page_mte_tagging(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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