mirror of
https://github.com/hardkernel/linux.git
synced 2026-06-03 17:51:57 +09:00
3cc31fa65d
iomap_is_partially_uptodate() is intended to check wither blocks within the selected range of a not-uptodate page are uptodate; if the range we care about is up to date, it's an optimization. However, the iomap implementation continues to check all blocks up to from+count, which is beyond the page, and can even be well beyond the iop->uptodate bitmap. I think the worst that will happen is that we may eventually find a zero bit and return "not partially uptodate" when it would have otherwise returned true, and skip the optimization. Still, it's clearly an invalid memory access that must be fixed. So: fix this by limiting the search to within the page as is done in the non-iomap variant, block_is_partially_uptodate(). Zorro noticed thiswhen KASAN went off for 512 byte blocks on a 64k page system: BUG: KASAN: slab-out-of-bounds in iomap_is_partially_uptodate+0x1a0/0x1e0 Read of size 8 at addr ffff800120c3a318 by task fsstress/22337 Reported-by: Zorro Lang <zlang@redhat.com> Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: Eric Sandeen <sandeen@sandeen.net> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
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.