Tetsuo Handa wrote on Wed, Mar 30, 2022 at 10:57:15AM +0900: > >> Please don't use schedule_work() if you need to use flush_scheduled_work(). > > > > In this case we don't call flush_scheduled_work -- ext4 does. > > Yes, that's why I changed recipients to ext4 people. Sorry, I hadn't noticed. 9p is the one calling schedule_work, so ultimately it really is the combinaison of the two, and not just ext4 that's wrong here. > > The problem is mixing in the two subsystems when someone (e.g. syzbot) > > opens an ext4 file and passes that fd to 9p when mounting with e.g. > > mount -t 9p -o rfdno=<no>,wfdno=<no> > > > > Frankly that's just not something I consider useful, interacting through > > 9p to a local file doesn't make sense except for testing. > > > > If that is a real problem, the simplest way out would be to just forbid > > non-socket FDs if it's something we can check. > > Do you mean that p9_fd_open() in net/9p/trans_fd.c does not need to > accept non-socket file descriptors? Yes, I can't think of any valid usage that would involve non-socket fd there. It might be useful to leave as a test vector, but if it causes problems I think it's perfectly OK to just refuse these. > Then, it's something you can check. You can use S_ISSOCK() like > e.g. netlink_getsockbyfilp() does Thanks for the example -- Dominique
