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

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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; struct tracer *tracer = tr->current_trace;
unsigned long flags; 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) { if (!tr->allocated_snapshot) {
internal_trace_puts("*** SNAPSHOT NOT ALLOCATED ***\n"); internal_trace_puts("*** SNAPSHOT NOT ALLOCATED ***\n");
internal_trace_puts("*** stopping trace here! ***\n"); internal_trace_puts("*** stopping trace here! ***\n");
@@ -460,6 +466,7 @@ void tracing_snapshot(void)
update_max_tr(tr, current, smp_processor_id()); update_max_tr(tr, current, smp_processor_id());
local_irq_restore(flags); local_irq_restore(flags);
} }
EXPORT_SYMBOL_GPL(tracing_snapshot);
static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf, static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf,
struct trace_buffer *size_buf, int cpu_id); struct trace_buffer *size_buf, int cpu_id);
@@ -493,16 +500,19 @@ void tracing_snapshot_alloc(void)
tracing_snapshot(); tracing_snapshot();
} }
EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
#else #else
void tracing_snapshot(void) void tracing_snapshot(void)
{ {
WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used"); WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
} }
EXPORT_SYMBOL_GPL(tracing_snapshot);
void tracing_snapshot_alloc(void) void tracing_snapshot_alloc(void)
{ {
/* Give warning */ /* Give warning */
tracing_snapshot(); tracing_snapshot();
} }
EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
#endif /* CONFIG_TRACER_SNAPSHOT */ #endif /* CONFIG_TRACER_SNAPSHOT */
/** /**