On Tue, 30 Jun 2015 22:18:03 +0800
Fengguang Wu <[email protected]> wrote:
> Hi Rostedt,
>
> FYI, this merge changes kernel crash to some more obvious kernel BUG
> message. If it's still not helpful, I can try bisect the old crash
> or split up the merge and bisect into them.
>
> git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
>
This has been a bug for some time. Does this fix it?
-- Steve
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index f060716b02ae..74bde81601a9 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -444,6 +444,7 @@ enum {
TRACE_CONTROL_BIT,
+ TRACE_BRANCH_BIT,
/*
* Abuse of the trace_recursion.
* As we need a way to maintain state if we are tracing the function
diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
index a87b43f49eb4..720ed604882e 100644
--- a/kernel/trace/trace_branch.c
+++ b/kernel/trace/trace_branch.c
@@ -49,7 +49,11 @@ probe_likely_condition(struct ftrace_branch_data *f, int
val, int expect)
if (unlikely(!tr))
return;
+ if (current->trace_recursion & TRACE_BRANCH_BIT)
+ return;
+
local_irq_save(flags);
+ current->trace_recursion |= TRACE_BRANCH_BIT;
cpu = raw_smp_processor_id();
data = per_cpu_ptr(tr->trace_buffer.data, cpu);
if (atomic_inc_return(&data->disabled) != 1)
@@ -82,6 +86,7 @@ probe_likely_condition(struct ftrace_branch_data *f, int val,
int expect)
out:
atomic_dec(&data->disabled);
+ current->trace_recursion &= ~TRACE_BRANCH_BIT;
local_irq_restore(flags);
}
--
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