On Sat, Mar 17, 2018 at 10:25:20AM -0400, Jeff Layton wrote: > From: Jeff Layton <jlayton@xxxxxxxxxx> > > POSIX mandates that open fds and their associated file locks should be > preserved across an execve. This works, unless the process is > multithreaded at the time that execve is called. > > In that case, we'll end up unsharing the files_struct but the locks will > still have their fl_owner set to the address of the old one. Eventually, > when the other threads die and the last reference to the old > files_struct is put, any POSIX locks get torn down since it looks like > a close occurred on them. > > The result is that all of your open files will be intact with none of > the locks you held before execve. The simple answer to this is "use OFD > locks", but this is a nasty surprise and it violates the spec. > > On a successful execve, change ownership of any POSIX file_locks > associated with the old files_struct to the new one, if we ended up > swapping it out. TBH, I don't like the way you implement that. Why not simply use iterate_fd()?
