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Ard Biesheuvel
b9bc36704c
ARM, xtensa: highmem: avoid clobbering non-page aligned memory reservations
free_highpages() iterates over the free memblock regions in high memory, and marks each page as available for the memory management system. Until commit cddb5ddf2b76 ("arm, xtensa: simplify initialization of high memory pages") it rounded beginning of each region upwards and end of each region downwards. However, after that commit free_highmem() rounds the beginning and end of each region downwards, and we may end up freeing a page that is memblock_reserve()d, resulting in memory corruption. Restore the original rounding of the region boundaries to avoid freeing reserved pages. Fixes: cddb5ddf2b76 ("arm, xtensa: simplify initialization of high memory pages") Link: https://lore.kernel.org/r/20201029110334.4118-1-ardb@kernel.org/ Link: https://lore.kernel.org/r/20201031094345.6984-1-rppt@kernel.org Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Co-developed-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Acked-by: Max Filippov <jcmvbkbc@gmail.com>
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.
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