On 2022/03/30 8:51, Dominique Martinet wrote: > Tetsuo Handa wrote on Wed, Mar 30, 2022 at 07:35:47AM +0900: >> This seems to be an example of >> https://lkml.kernel.org/r/49925af7-78a8-a3dd-bce6-cfc02e1a9236@xxxxxxxxxxxxxxxxxxx >> introduced by "ext4: truncate during setxattr leads to kernel panic". > > Thanks for the pointer > >> 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. > 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? Then, it's something you can check. You can use S_ISSOCK() like e.g. netlink_getsockbyfilp() does.
