On Thu, May 24, 2018 at 4:14 AM, Sergey Senozhatsky <sergey.senozhatsky.w...@gmail.com> wrote: >> First, we should ask what we expect from this feature. > > Yeah. Can't really comment on this, it's up to Tetsuo and Dmitry to > decide. So far I've seen slightly different requirements/expectations.
The root problem is that it's not possible to make sense out of kernel output if message takes more than 1 line (or output non-atomically with several printk's) because of intermixed output from several tasks/interrupts/etc. For example, it's not generally possible to recover crash stack trace, because one gets random mix of frames. Humans usually, but not always, can restore most of the sense. So the goal is to make this ought-to-be-simple task actually simple and not requiring human intelligence and time each time. Prefixing each line with task/cpu/interrupt context should do the trick as it will be possible to split kernel output into multiple independent streams and analyze them independently. In our context (syzbot testing) we can enable an additional config, and adopt parser to understand additional line prefix. But I don't know how prefixing lines fits into a larger picture. Does it make sense to thought out a potential extension story for this format? E.g. user specifies set of extension records that are dumped before each line, and then can unambiguously parse them? I guess some consoles/interfaces will never be extended to provide access to the extension records, so it can make sense to make them accessible in text format too (optionally).
