cbab3cac94
commit 15420269b02a63ed8c1841905d8b8b2403246004 upstream.
The helpers that are used to implement copy_from_kernel_nofault() and
copy_to_kernel_nofault() cast a void* to a pointer to a wider type,
which may result in alignment faults on ARM if the compiler decides to
use double-word or multiple-word load/store instructions.
Only configurations that define CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS=y
are affected, given that commit 2423de2e6f4d ("ARM: 9115/1: mm/maccess:
fix unaligned copy_{from,to}_kernel_nofault") ensures that dst and src
are sufficiently aligned otherwise.
So use the unaligned accessors for accessing dst and src in cases where
they may be misaligned.
Cc: <stable@vger.kernel.org> # depends on 2423de2e6f4d
Fixes: 2df4c9a741a0 ("ARM: 9112/1: uaccess: add __{get,put}_kernel_nofault")
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
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.