15 messages in org.freebsd.freebsd-hackersnullfs and named pipes.| From | Sent On | Attachments |
|---|---|---|
| Josef Karthauser | Feb 4, 2007 2:57 am | |
| Eric Anderson | Feb 6, 2007 4:48 pm | |
| Josef Karthauser | Feb 7, 2007 10:47 am | |
| Jeremie Le Hen | Feb 15, 2007 2:21 pm | |
| Josef Karthauser | Feb 15, 2007 3:22 pm | |
| Kostik Belousov | Feb 15, 2007 3:31 pm | |
| Josef Karthauser | Feb 15, 2007 4:34 pm | |
| Julian Elischer | Feb 15, 2007 6:11 pm | |
| Jeremie Le Hen | Feb 16, 2007 10:30 am | |
| Robert Watson | Feb 16, 2007 12:54 pm | |
| Kostik Belousov | Feb 16, 2007 2:36 pm | |
| Josef Karthauser | Feb 18, 2007 10:41 pm | |
| Robert Watson | Feb 19, 2007 2:01 pm | |
| Robert Watson | Feb 19, 2007 2:08 pm | |
| Robert Watson | Feb 19, 2007 2:28 pm |
| Subject: | nullfs and named pipes. | |
|---|---|---|
| From: | Robert Watson (rwat...@FreeBSD.org) | |
| Date: | Feb 19, 2007 2:08:17 pm | |
| List: | org.freebsd.freebsd-hackers | |
On Mon, 19 Feb 2007, Robert Watson wrote:
On Sun, 18 Feb 2007, Josef Karthauser wrote:
Well, the worry would be that you would be replacing a clean error on failure with an occasional panic, the normal symptom of a race condition.
I think I'm alright with the VFIFO case above, but I'm quite uncomfortable with the VSOCK case. In particular, I suspect that if the socket is closed, v_un will be reset in the lower layer, but continue to be a stale pointer in the upper layer, leading to accessing free'd or re-allocated kernel memory resulting in much badness. I've noticed tested this, but you might give it a try and see what happens.
Bad typing day. Should read "not tested this". In any case, you get the idea: the problem here is a potential coherency issue on contents of v_un between the two file system layers.
Robert N M Watson Computer Laboratory University of Cambridge