On Fri 2014-11-14 23:59:13, Steven Rostedt wrote: > From: "Steven Rostedt (Red Hat)" <[email protected]> > > When trigger_all_cpu_backtrace() is called on x86, it will trigger an > NMI on each CPU and call show_regs(). But this can lead to a hard lock > up if the NMI comes in on another printk(). > > In order to avoid this, when the NMI triggers, it switches the printk > routine for that CPU to call a NMI safe printk function that records the > printk in a per_cpu seq_buf descriptor. After all NMIs have finished > recording its data, the seq_bufs are printed in a safe context. > > Link: http://lkml.kernel.org/p/[email protected] > > Tested-by: Jiri Kosina <[email protected]> > Acked-by: Jiri Kosina <[email protected]> > Acked-by: Paul E. McKenney <[email protected]> > Signed-off-by: Steven Rostedt <[email protected]>
Reviewed-by: Petr Mladek <[email protected]> I really like that the NMI part is fast and we do not longer block many CPUs until the others are finished with priting. Best Regards, Petr -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
