tracing: Add proper check for irq_depth routines

The check_irq_entry and check_irq_return could be called
from graph event context. In such case there's no graph
private data allocated. Adding checks to handle this case.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
LKML-Reference: <20100924154102.GB1818@jolsa.brq.redhat.com>

[ Fixed some grammar in the comments ]

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 20 insertions, 4 deletions

diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index ef49e9370b2..4c58ccc6427 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -888,12 +888,20 @@ check_irq_entry(struct trace_iterator *iter, u32 flags,
                 unsigned long addr, int depth)
 {
         int cpu = iter->cpu;
+        int *depth_irq;
         struct fgraph_data *data = iter->private;
-        int *depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
 
-        if (flags & TRACE_GRAPH_PRINT_IRQS)
+        /*
+         * If we are either displaying irqs, or we got called as
+         * a graph event and private data does not exist,
+         * then we bypass the irq check.
+         */
+        if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
+            (!data))
                 return 0;
 
+        depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
+
         /*
          * We are inside the irq code
          */
@@ -926,12 +934,20 @@ static int
 check_irq_return(struct trace_iterator *iter, u32 flags, int depth)
 {
         int cpu = iter->cpu;
+        int *depth_irq;
         struct fgraph_data *data = iter->private;
-        int *depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
 
-        if (flags & TRACE_GRAPH_PRINT_IRQS)
+        /*
+         * If we are either displaying irqs, or we got called as
+         * a graph event and private data does not exist,
+         * then we bypass the irq check.
+         */
+        if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
+            (!data))
                 return 0;
 
+        depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
+
         /*
          * We are not inside the irq code.
          */