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aa3c291fd2
commit d71fa842d3 upstream.
ARM_LPAE_LVL_IDX() takes into account concatenated PGDs and can return
an index spanning multiple page-table pages given a sufficiently large
input address. However, when the resulting index is used to calculate
the number of remaining entries in the page, the possibility of
concatenation is ignored and we end up computing a negative upper bound:
max_entries = ARM_LPAE_PTES_PER_TABLE(data) - map_idx_start;
On the map path, this results in a negative 'mapped' value being
returned but on the unmap path we can leak child tables if they are
skipped in __arm_lpae_free_pgtable().
Introduce an arm_lpae_max_entries() helper to convert a table index into
the remaining number of entries within a single page-table page.
Cc: <stable@vger.kernel.org>
Signed-off-by: Mostafa Saleh <smostafa@google.com>
Link: https://lore.kernel.org/r/20241024162516.2005652-2-smostafa@google.com
[will: Tweaked comment and commit message]
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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 reStructuredText 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.