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