Philip Guenther <guent...@gmail.com> wrote: > The warning is not that a single filesystem is being locked recursively by a > single > thread, but just that a single thread is holding locks on multiple > filesystems.
vfs_stall() needs to grab locks on all filesystems, to stop a variety of filesystem transactions. (Other types of transactions are blocked in other ways). sys_umount() grabs locks on all filesystems above it, to stop anyone from doing a parallel mount/unmount along the same path. This is all normal.