[tip:perf/core] tracing: Add proper check for irq_depth routines

From: tip-bot for Jiri Olsa
Date: Wed Oct 20 2010 - 00:59:34 EST


Commit-ID: a9d61173dc1cb63e660ae89e874e51ba4fd2f991
Gitweb: http://git.kernel.org/tip/a9d61173dc1cb63e660ae89e874e51ba4fd2f991
Author: Jiri Olsa <jolsa@xxxxxxxxxx>
AuthorDate: Fri, 24 Sep 2010 17:41:02 +0200
Committer: Steven Rostedt <rostedt@xxxxxxxxxxx>
CommitDate: Mon, 18 Oct 2010 10:53:25 -0400

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@xxxxxxxxxx>
LKML-Reference: <20100924154102.GB1818@xxxxxxxxxxxxxxxxxxxx>

[ Fixed some grammar in the comments ]

Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
kernel/trace/trace_functions_graph.c | 24 ++++++++++++++++++++----
1 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index ef49e93..4c58ccc 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.
*/
--
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