From: Dave Hansen Date: Thu, 7 Aug 2014 17:58:41 +0000 (-0700) Subject: x86/mm: Fix RCU splat from new TLB tracepoints X-Git-Tag: v3.17-rc2~5^2~4 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=7c7f1547b627092737493f0781780af85cc9b1a4;p=linux.git x86/mm: Fix RCU splat from new TLB tracepoints Dave Jones reported seeing a bug from one of my TLB tracepoints: http://lkml.kernel.org/r/20140806181801.GA4605@redhat.com According to Paul McKenney, the right way to fix this is adding an _rcuidle suffix to the tracepoint. http://lkml.kernel.org/r/20140807065055.GA5821@linux.vnet.ibm.com This patch does just that. Reported-by: Dave Jones , Signed-off-by: Dave Hansen Reviewed-by: Paul E. McKenney Cc: Dave Hansen Cc: Linus Torvalds Link: http://lkml.kernel.org/r/20140807175841.5C92D878@viggo.jf.intel.com Signed-off-by: Ingo Molnar --- diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index 1fe33987de02..98b7976d44af 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -49,7 +49,13 @@ void leave_mm(int cpu) if (cpumask_test_cpu(cpu, mm_cpumask(active_mm))) { cpumask_clear_cpu(cpu, mm_cpumask(active_mm)); load_cr3(swapper_pg_dir); - trace_tlb_flush(TLB_FLUSH_ON_TASK_SWITCH, TLB_FLUSH_ALL); + /* + * This gets called in the idle path where RCU + * functions differently. Tracing normally + * uses RCU, so we have to call the tracepoint + * specially here. + */ + trace_tlb_flush_rcuidle(TLB_FLUSH_ON_TASK_SWITCH, TLB_FLUSH_ALL); } } EXPORT_SYMBOL_GPL(leave_mm);