mm/debug_vm_pgtable: fix corrupted page flag
In page table entry modifying tests, set_xxx_at() are used to populate the page table entries. On ARM64, PG_arch_1 (PG_dcache_clean) flag is set to the target page flag if execution permission is given. The logic exits since commit 4f04d8f0 ("arm64: MMU definitions"). The page flag is kept when the page is free'd to buddy's free area list. However, it will trigger page checking failure when it's pulled from the buddy's free area list, as the following warning messages indicate. BUG: Bad page state in process memhog pfn:08000 page:0000000015c0a628 refcount:0 mapcount:0 \ mapping:0000000000000000 index:0x1 pfn:0x8000 flags: 0x7ffff8000000800(arch_1|node=0|zone=0|lastcpupid=0xfffff) raw: 07ffff8000000800 dead000000000100 dead000000000122 0000000000000000 raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: PAGE_FLAGS_CHECK_AT_PREP flag(s) set This fixes the issue by clearing PG_arch_1 through flush_dcache_page() after set_xxx_at() is called. For architectures other than ARM64, the unexpected overhead of cache flushing is acceptable. Link: https://lkml.kernel.org/r/20210809092631.1888748-13-gshan@redhat.com Fixes: a5c3b9ff ("mm/debug_vm_pgtable: add tests validating advanced arch page table helpers") Signed-off-by:Gavin Shan <gshan@redhat.com> Reviewed-by:
Anshuman Khandual <anshuman.khandual@arm.com> Tested-by: Christophe Leroy <christophe.leroy@csgroup.eu> [powerpc 8xx] Tested-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com> [s390] Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chunyu Hu <chuhu@redhat.com> Cc: Qian Cai <cai@lca.pw> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will@kernel.org> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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