Commit-ID: 7c7f1547b627092737493f0781780af85cc9b1a4
Gitweb: http://git.kernel.org/tip/7c7f1547b627092737493f0781780af85cc9b1a4
Author: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
AuthorDate: Thu, 7 Aug 2014 10:58:41 -0700
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Fri, 8 Aug 2014 10:35:00 +0200
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@xxxxxxxxxx
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@xxxxxxxxxxxxxxxxxx
This patch does just that.
Reported-by: Dave Jones <davej@xxxxxxxxxx>,
Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Reviewed-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Dave Hansen <dave@xxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20140807175841.5C92D878@xxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/mm/tlb.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 1fe3398..98b7976 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);
--
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