It seems to me that all of this assumes only one namespace could be relevant to any given printk. I don't think that's a safe assumption -- it might be that multiple namespaces with differing user/syslog namespaces are relevant to the same printk. What should happen then?
Stepping closer to practical containers: "syslog" namespaces
Posted Dec 7, 2012 2:22 UTC (Fri) by Beolach (subscriber, #77384)
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Possibly w/ multiple nsprintk() calls, specifying all of the relevant namespaces (1 in each call). Assuming you can identify them... but hopefully that wouldn't be difficult (if it's not possible, then maybe it is a safe assumption that the message is only relevant to one namespace).