7ab0b7cb89
copy_page() and clear_page() expect page aligned destination, and use dcbz instruction to clear entire cache lines based on the assumption that the destination is cache aligned. As shown during analysis of a bug in BTRFS filesystem, a misaligned copy_page() can create bugs that are difficult to locate (see Link). Add an explicit WARNING when copy_page() or clear_page() are called with misaligned destination. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://bugzilla.kernel.org/show_bug.cgi?id=204371 Link: https://lore.kernel.org/r/c6cea38f90480268d439ca44a645647e260fff09.1565941808.git.christophe.leroy@c-s.fr
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.