Re: [GIT PULL] tracing/NMI/printk: Use seq_buf for safe printing from NMI context

From: Linus Torvalds
Date: Wed Dec 10 2014 - 23:20:46 EST

On Mon, Dec 8, 2014 at 7:08 AM, Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> One added bonus is that this code also makes the NMI dump stack work on
> PREEMPT_RT kernels. As printk() includes sleeping locks on PREEMPT_RT,
> printk() only writes to console if the console does not use any
> rt_mutex converted spin locks. Which a lot do.

Would it perhaps be possible/reasonable to also use this to get rid of
the horrible "early_printk()" stuff, and switch to "vprintk_default"
only once the system is sufficiently up-and-running?

Hmm? Not that there are very many users of that horrible thing.

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