On Thu, Feb 5, 2015 at 8:14 AM, Dave Hansen <dave@xxxxxxxx> wrote: > On 02/04/2015 05:53 PM, Sedat Dilek wrote: >> The architecture-specific switch_mm() function can be called by offline >> CPUs, but includes event tracing, which cannot be legally carried out >> on offline CPUs. This results in a lockdep-RCU splat. This commit fixes >> this splat by omitting the tracing when the CPU is offline. > ... >>>> >> > load_cr3(next->pgd); >>>> >> > - trace_tlb_flush(TLB_FLUSH_ON_TASK_SWITCH, TLB_FLUSH_ALL); >>>> >> > + if (cpu_online(smp_processor_id())) >>>> >> > + trace_tlb_flush(TLB_FLUSH_ON_TASK_SWITCH, TLB_FLUSH_ALL); > > Is this, perhaps, something that we should be doing in the generic trace > code so that all of the trace users don't have to worry about it? Also, > this patch will add overhead to the code when tracing is off. It would > be best if we could manage to make the cpu_online() check only in the > cases where the tracepoint is on. Hi Dave, thanks for your feedback. I have just seen that I again see the call-trace. Maybe you can discuss with Paul and others or offer a proposal patch. I should really do something for my recovery (influenza). Instead of laying lazy in my bed I thought to update my Linux kernels and graphics driver stack which made me happy. Regards, - Sedat - -- To unsubscribe from this list: send the line "unsubscribe linux-next" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
