https://github.com/torvalds/linux
Revision d08af0a59684e18a51aa4bfd24c658994ea3fc5b authored by Joao Martins on 15 July 2021, 04:27:11 UTC, committed by Linus Torvalds on 15 July 2021, 17:13:49 UTC
Commit 82e5d378b0e47 ("mm/hugetlb: refactor subpage recording")
refactored the count of subpages but missed an edge case when @vaddr is
not aligned to PAGE_SIZE e.g.  when close to vma->vm_end.  It would then
errousnly set @refs to 0 and record_subpages_vmas() wouldn't set the
@pages array element to its value, consequently causing the reported
null-deref by syzbot.

Fix it by aligning down @vaddr by PAGE_SIZE in @refs calculation.

Link: https://lkml.kernel.org/r/20210713152440.28650-1-joao.m.martins@oracle.com
Fixes: 82e5d378b0e47 ("mm/hugetlb: refactor subpage recording")
Reported-by: syzbot+a3fcd59df1b372066f5a@syzkaller.appspotmail.com
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent b3b2177
History
Tip revision: d08af0a59684e18a51aa4bfd24c658994ea3fc5b authored by Joao Martins on 15 July 2021, 04:27:11 UTC
mm/hugetlb: fix refs calculation from unaligned @vaddr
Tip revision: d08af0a
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