From: Dave Hansen <[email protected]>
This is a bug fix that needs to be pushed to mainline before the
3.17 release.
Dave Jones reported seeing a bug from one of my TLB tracepoints:
http://lkml.kernel.org/r/[email protected]
According to Paul McKenney, the right way to fix this is adding
an _rcuidle suffix to the tracepoint.
http://lkml.kernel.org/r/[email protected]
This patch does just that.
Signed-off-by: Dave Hansen <[email protected]>
Reported-by: Dave Jones <[email protected]>,
Cc: [email protected]
---
b/arch/x86/mm/tlb.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff -puN arch/x86/mm/tlb.c~mm-fix-rcu-splat-from-tlb-tracepoints
arch/x86/mm/tlb.c
--- a/arch/x86/mm/tlb.c~mm-fix-rcu-splat-from-tlb-tracepoints 2014-08-07
10:55:43.312283542 -0700
+++ b/arch/x86/mm/tlb.c 2014-08-07 10:56:49.763352575 -0700
@@ -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);
_
--
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