On Tue, 2022-02-08 at 13:40 -0800, Abhinav Kumar wrote: > > > I am checking what usermode sees and will get back ( I didnt see an > error do most likely it was EOF ). I didnt follow the second part. I think probably it got -ENODEV, looking at kernfs_file_read_iter(). > If the file descriptor read returns EOF, even if we consider them > separate how will it resolve this issue? > > My earlier questions were related to fixing it in devcoredump to detect > and fix it there. Are you suggesting to fix in usermode instead? How? > Yeah, no, you cannot fix it in userspace. But I just followed the rabbit hole down kernfs and all, and it looks like indeed the read would be cut short with -ENODEV, sorry. It doesn't look like there's good API for this, but it seems at least from the underlying kernfs POV it should be possible to get_device() in open and put_device() in release, so that the device sticks around while somebody has the file open? It's entirely virtual, so this should be OK? johannes
