https://github.com/torvalds/linux
Revision 04f7ce3f07ce39b1a3ca03a56b238a53acc52cfd authored by Gerald Schaefer on 05 June 2021, 03:01:18 UTC, committed by Linus Torvalds on 05 June 2021, 15:58:11 UTC
In pmd/pud_advanced_tests(), the vaddr is aligned up to the next pmd/pud entry, and so it does not match the given pmdp/pudp and (aligned down) pfn any more. For s390, this results in memory corruption, because the IDTE instruction used e.g. in xxx_get_and_clear() will take the vaddr for some calculations, in combination with the given pmdp. It will then end up with a wrong table origin, ending on ...ff8, and some of those wrongly set low-order bits will also select a wrong pagetable level for the index addition. IDTE could therefore invalidate (or 0x20) something outside of the page tables, depending on the wrongly picked index, which in turn depends on the random vaddr. As result, we sometimes see "BUG task_struct (Not tainted): Padding overwritten" on s390, where one 0x5a padding value got overwritten with 0x7a. Fix this by aligning down, similar to how the pmd/pud_aligned pfns are calculated. Link: https://lkml.kernel.org/r/20210525130043.186290-2-gerald.schaefer@linux.ibm.com Fixes: a5c3b9ffb0f40 ("mm/debug_vm_pgtable: add tests validating advanced arch page table helpers") Signed-off-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: <stable@vger.kernel.org> [5.9+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 0711f0d
Tip revision: 04f7ce3f07ce39b1a3ca03a56b238a53acc52cfd authored by Gerald Schaefer on 05 June 2021, 03:01:18 UTC
mm/debug_vm_pgtable: fix alignment for pmd/pud_advanced_tests()
mm/debug_vm_pgtable: fix alignment for pmd/pud_advanced_tests()
Tip revision: 04f7ce3
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