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fcbad8293d
The current xt_time driver suffers from the y2038 overflow on 32-bit architectures, when the time of day calculations break. Also, on both 32-bit and 64-bit architectures, there is a problem with info->date_start/stop, which is part of the user ABI and overflows in in 2106. Fix the first issue by using time64_t and explicit calls to div_u64() and div_u64_rem(), and document the seconds issue. The explicit 64-bit division is unfortunately slower on 32-bit architectures, but doing it as unsigned lets us use the optimized division-through-multiplication path in most configurations. This should be fine, as the code already does not allow any negative time of day values. Using u32 seconds values consistently would probably also work and be a little more efficient, but that doesn't feel right as it would propagate the y2106 overflow to more place rather than fewer. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.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.