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commit229e225376upstream. do_pages_move does not handle compat pointers for the page list. correctly. Add in_compat_syscall check and appropriate get_user fetch when iterating the page list. It makes the syscall in compat mode (32-bit userspace, 64-bit kernel) work the same way as the native 32-bit syscall again, restoring the behavior before my broken commit5b1b561ba7("mm: simplify compat_sys_move_pages"). More specifically, my patch moved the parsing of the 'pages' array from the main entry point into do_pages_stat(), which left the syscall working correctly for the 'stat' operation (nodes = NULL), while the 'move' operation (nodes != NULL) is now missing the conversion and interprets 'pages' as an array of 64-bit pointers instead of the intended 32-bit userspace pointers. It is possible that nobody noticed this bug because the few applications that actually call move_pages are unlikely to run in compat mode because of their large memory requirements, but this clearly fixes a user-visible regression and should have been caught by ltp. Link: https://lkml.kernel.org/r/20231003144857.752952-1-gregory.price@memverge.com Fixes:5b1b561ba7("mm: simplify compat_sys_move_pages") Signed-off-by: Gregory Price <gregory.price@memverge.com> Reported-by: Arnd Bergmann <arnd@arndb.de> Co-developed-by: Arnd Bergmann <arnd@arndb.de> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> 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.