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tracing: Let tracing_snapshot() be used by modules but not NMI 

Add EXPORT_SYMBOL_GPL() to let the tracing_snapshot() functions be
called from modules.

Also add a test to see if the snapshot was called from NMI context
and just warn in the tracing buffer if so, and return.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (Red Hat) 2013-03-09 00:56:08 -05:00 committed by Steven Rostedt
parent ca268da6e4
commit 1b22e382ab
1 changed files with 10 additions and 0 deletions
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10
kernel/trace/trace.c
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@ -442,6 +442,12 @@ void tracing_snapshot(void)
struct tracer *tracer = tr->current_trace;
unsigned long flags;
if (in_nmi()) {
internal_trace_puts("*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
internal_trace_puts("*** snapshot is being ignored ***\n");
return;
}
if (!tr->allocated_snapshot) {
internal_trace_puts("*** SNAPSHOT NOT ALLOCATED ***\n");
internal_trace_puts("*** stopping trace here! ***\n");
@ -460,6 +466,7 @@ void tracing_snapshot(void)
update_max_tr(tr, current, smp_processor_id());
local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(tracing_snapshot);
static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf,
struct trace_buffer *size_buf, int cpu_id);
@ -493,16 +500,19 @@ void tracing_snapshot_alloc(void)
tracing_snapshot();
}
EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
#else
void tracing_snapshot(void)
{
WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
}
EXPORT_SYMBOL_GPL(tracing_snapshot);
void tracing_snapshot_alloc(void)
{
/* Give warning */
tracing_snapshot();
}
EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
#endif /* CONFIG_TRACER_SNAPSHOT */
/**