fee5eaecca
Syzbot reports that in its stress test for resize ioctl, the log writing function nilfs_segctor_do_construct hits a WARN_ON in nilfs_segctor_truncate_segments(). It turned out that there is a problem with the current implementation of the resize ioctl, which changes the writable range on the device (the range of allocatable segments) at the end of the resize process. This order is necessary for file system expansion to avoid corrupting the superblock at trailing edge. However, in the case of a file system shrink, if log writes occur after truncating out-of-bounds trailing segments and before the resize is complete, segments may be allocated from the truncated space. The userspace resize tool was fine as it limits the range of allocatable segments before performing the resize, but it can run into this issue if the resize ioctl is called alone. Fix this issue by changing nilfs_sufile_resize() to update the range of allocatable segments immediately after successful truncation of segment space in case of file system shrink. Link: https://lkml.kernel.org/r/20230524094348.3784-1-konishi.ryusuke@gmail.com Fixes: 4e33f9eab07e ("nilfs2: implement resize ioctl") Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com> Reported-by: syzbot+33494cd0df2ec2931851@syzkaller.appspotmail.com Closes: https://lkml.kernel.org/r/0000000000005434c405fbbafdc5@google.com Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.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.