Messages in this thread | | | From | David Howells <> | Subject | Re: [PATCH 1/1] exec: do not sleep in TASK_TRACED under ->cred_guard_mutex | Date | Fri, 04 Sep 2009 09:43:40 +0100 |
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Roland McGrath <roland@redhat.com> wrote:
> I certainly think it's right to hold the mutex only as long as necessary. > Clearly holding it when we stop is wrong.
As far as I can tell, we don't hold it when we stop for debugging, or stop on signal.
> I'm a bit concerned about holding it for arbitrary periods while we block > in the filesystem code. e.g., consider the scenario with a hangs-forever > NFS server or suchlike. But I'm not sure there is a reasonable way around > that one.
If you drop the sem before committing the creds, you have to recalculate the new credentials.
> The paired calls that leave the mutex locked in between should have some > clear comments calling attention to their pairing. Aside from that making > sure that subtlety is clear, I don't see any problems in the patch off hand. > But I haven't scoured the code path lately to have full confidence. > I'd like to hear David's reactions.
Looking at the patch description, I don't see how the patch it relevant to the problem. There must be something else, either a call that's now being skipped, or it's a matter of timing.
David
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