Hans Holmberg 0d92a3eaa6 null_blk: set dma alignment to logical block size
This driver assumes that bio vectors are memory aligned to the logical
block size, so set the queue limit to reflect that.

Unless we set up the limit based on the logical block size, we will go
out of page bounds in copy_to_nullb / copy_from_nullb.

Apparently this wasn't noticed so far because none of the tests generate
such buffers, but since commit 851c4c96db ("xfs: implement
XFS_IOC_DIOINFO in terms of vfs_getattr") xfstests generates unaligned
I/O, which now lead to memory corruption when using null_blk devices
with 4k block size.

Fixes: bf8d08532b ("iomap: add support for dma aligned direct-io")
Fixes: b1a000d3b8 ("block: relax direct io memory alignment")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Hans Holmberg <hans.holmberg@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-31 09:03:12 -06:00

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 reStructuredText 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.
S
Description
No description provided
Readme 5.1 GiB
Languages
C 97%
Assembly 1%
Shell 0.6%
Rust 0.5%
Python 0.4%
Other 0.3%