On Fri, Sep 13, 2024 at 01:57:04PM -0400, trondmy@xxxxxxxxxx wrote:
> If the caller supplies an iocb->ki_pos value that is close to the
> filesystem upper limit, and an iterator with a count that causes us to
> overflow that limit, then filemap_read() enters an infinite loop.
Are we guaranteed that ki_pos lies in the range [0..s_maxbytes)?
I'm not too familiar with the upper paths of the VFS and what guarantees
we can depend on. If we are guaranteed that, could somebody document
it (and indeed create kernel-doc for struct kiocb)?
>
> - iov_iter_truncate(iter, inode->i_sb->s_maxbytes);
> + iov_iter_truncate(iter, inode->i_sb->s_maxbytes - iocb->ki_pos);
> folio_batch_init(&fbatch);
>
> do {
> --
> 2.46.0
>
