Joanne Koong 82b60ffbb5 iomap: adjust read range correctly for non-block-aligned positions
[ Upstream commit 7aa6bc3e8766990824f66ca76c19596ce10daf3e ]

iomap_adjust_read_range() assumes that the position and length passed in
are block-aligned. This is not always the case however, as shown in the
syzbot generated case for erofs. This causes too many bytes to be
skipped for uptodate blocks, which results in returning the incorrect
position and length to read in. If all the blocks are uptodate, this
underflows length and returns a position beyond the folio.

Fix the calculation to also take into account the block offset when
calculating how many bytes can be skipped for uptodate blocks.

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Tested-by: syzbot@syzkaller.appspotmail.com
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-01-11 15:21:41 +01:00
2022-09-28 09:02:20 +02:00
2025-12-07 06:18:54 +09:00

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 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.
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