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2532e6c74a
cma_init_reserved_mem() checks base and size alignment with CMA_MIN_ALIGNMENT_BYTES. However, some users might call this during early boot when pageblock_order is 0. That means if base and size does not have pageblock_order alignment, it can cause functional failures during cma activate area. So let's enforce pageblock_order to be non-zero during cma_init_reserved_mem() to catch such wrong usages. 1. This was seen with fadump on PowerPC which was calling cma_init_reserved_mem() before the pageblock_order was initialized. This is now fixed in the fadump on PowerPC itself. The details of that can be found in the patch including the userspace-visible effect of the issue [1]. 2. However it was also decided that we should add a stronger enforcement check within cma_init_reserved_mem() to catch such wrong usages [2]. Hence this patch. This is ok to be in -next and there is no "Fixes" tag required for this patch. [1]: https://lore.kernel.org/all/3ae208e48c0d9cefe53d2dc4f593388067405b7d.1729146153.git.ritesh.list@gmail.com/ [2]: https://lore.kernel.org/all/83eb128e-4f06-4725-a843-a4563f246a44@redhat.com/ Link: https://lkml.kernel.org/r/e274344b44d5f80fa54c52f530387257fe99ec65.1731505681.git.ritesh.list@gmail.com Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by: Andrew Morton <akpm@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 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.