Messages in this thread | | | Date | Thu, 20 May 2010 11:47:32 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: PREEMPT_RT (2.6.33-rt17) disabled printk-to-console after console_init |
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Please stop top posting !
On Thu, 20 May 2010, Sujit K M wrote:
> >>> Well, obviously it's unsafe if you remove safety checks. And if you > >>> care to look at the changelog of kernel/printk.c you'll find out why. > >> > >> Hmm... did a quick look and could not find anything related there. > >> Could you please give a pointer?
Gah, yes. The changelog of the commit is not really helpful. Let me explain:
The console drivers might take locks, which are converted to "sleeping locks" in preempt-rt. As a result we cannot call into those drivers from atomic contexts. And that's what the checks in the printk code prevent.
Hope that helps.
Thanks,
tglx
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