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A dead loop can be triggered in f2fs_fiemap() using the test case as below: ... fd = open(); fallocate(fd, 0, 0, 4294967296); ioctl(fd, FS_IOC_FIEMAP, fiemap_buf); ... It's caused by an overflow in __get_data_block(): ... bh->b_size = map.m_len << inode->i_blkbits; ... map.m_len is an unsigned int, and bh->b_size is a size_t which is 64 bits on 64 bits archtecture, type conversion from an unsigned int to a size_t will result in an overflow. In the above-mentioned case, bh->b_size will be zero, and f2fs_fiemap() will call get_data_block() at block 0 again an again. Fix this by adding a force conversion before left shift. Signed-off-by: Wei Fang <fangwei1@huawei.com> Acked-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.