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Ryan Roberts
d6705bcc5f
[ Upstream commit4795d205d7] kmsan_free_page() is called by the page allocator's free_pages_prepare() during page freeing. Its job is to poison all the memory covered by the page. It can be called with an order-0 page, a compound high-order page or a non-compound high-order page. But page_size() only works for order-0 and compound pages. For a non-compound high-order page it will incorrectly return PAGE_SIZE. The implication is that the tail pages of a high-order non-compound page do not get poisoned at free, so any invalid access while they are free could go unnoticed. It looks like the pages will be poisoned again at allocation time, so that would bookend the window. Fix this by using the order parameter to calculate the size. Link: https://lkml.kernel.org/r/20260104134348.3544298-1-ryan.roberts@arm.com Fixes:b073d7f8ae("mm: kmsan: maintain KMSAN metadata for page operations") Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> Reviewed-by: Alexander Potapenko <glider@google.com> Tested-by: Alexander Potapenko <glider@google.com> Cc: Dmitriy Vyukov <dvyukov@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Marco Elver <elver@google.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> [ Adjust context ] Signed-off-by: Sasha Levin <sashal@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 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.