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>

diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index ef49e9370b25e8b525edbc150c9350010dd19cd6..4c58ccc6427cf25409b7e7d76432824f3bea07cc 100644 (file)
--- 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.
         */