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d08af0a596
Commit82e5d378b0("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:82e5d378b0("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>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.