If a page fault occurs while copying the first byte, this function resets one byte before dst. As a consequence, an address could be modified and leaded to kernel crashes if case the modified address was accessed later. Fixes: b58294ead14c ("maccess: allow architectures to provide kernel probing directly") Signed-off-by: Alban Crequy <albancrequy@linux.microsoft.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Tested-by: Francis Laniel <flaniel@linux.microsoft.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: <stable@vger.kernel.org> [5.8] Link: https://lore.kernel.org/bpf/20221110085614.111213-2-albancrequy@linux.microsoft.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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