Commits
Miklos Szeredi committed 07fbef9a6e1
fix up iter on short count in fuse_direct_io() commit f658adeea45e430a24c7a157c3d5448925ac2038 upstream. fuse_direct_io() can end up advancing the iterator by more than the amount of data read or written. This case is handled by the generic code if going through ->direct_IO(), but not in the FOPEN_DIRECT_IO case. Fix by reverting the extra bytes from the iterator in case of error or a short count. To test: install lxcfs, then the following testcase int fd = open("/var/lib/lxcfs/proc/uptime", O_RDONLY); sendfile(1, fd, NULL, 16777216); sendfile(1, fd, NULL, 16777216); will spew WARN_ON() in iov_iter_pipe(). Reported-by: Peter Geis <pgwipeout@gmail.com> Reported-by: Al Viro <viro@zeniv.linux.org.uk> Fixes: 3c3db095b68c ("fuse: use iov_iter based generic splice helpers") Cc: <stable@vger.kernel.org> # v5.1 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>