406fae6c79
commit 2c7f497ac274a14330208b18f6f734000868ebf9 upstream. In SHOW(), the variable 'n' is of type 'size_t.' While there is a conditional check to verify that 'n' is not equal to zero before executing the 'do_div' macro, concerns arise regarding potential division by zero error in 64-bit environments. The concern arises when 'n' is 64 bits in size, greater than zero, and the lower 32 bits of it are zeros. In such cases, the conditional check passes because 'n' is non-zero, but the 'do_div' macro casts 'n' to 'uint32_t,' effectively truncating it to its lower 32 bits. Consequently, the 'n' value becomes zero. To fix this potential division by zero error and ensure precise division handling, this commit replaces the 'do_div' macro with div64_u64(). div64_u64() is designed to work with 64-bit operands, guaranteeing that division is performed correctly. This change enhances the robustness of the code, ensuring that division operations yield accurate results in all scenarios, eliminating the possibility of division by zero, and improving compatibility across different 64-bit environments. Found by Linux Verification Center (linuxtesting.org) with SVACE. Signed-off-by: Rand Deeb <rand.sec96@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Coly Li <colyli@suse.de> Link: https://lore.kernel.org/r/20231120052503.6122-5-colyli@suse.de Signed-off-by: Jens Axboe <axboe@kernel.dk> 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.