[patch] perf/trace properly use u64 to hold event_id

[patch] perf/trace properly use u64 to hold event_id

[Vince Weaver]

The 64-bit attr.config value for perf trace events was being copied into
an "int" before doing a comparison, meaning the top 32 bits were
being truncated.

As far as I can tell this didn't cause any errors, but it did mean
it was possible to create valid aliases for all the tracepoint ids
which I don't think was intended.  (For example, 0xffffffff00000018
and 0x18 both enable the same tracepoint).

Signed-off-by: Vince Weaver <vincent.weaver@maine.edu>

diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index 78e27e3..280c3db0 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -173,7 +173,7 @@ static int perf_trace_event_init(struct ftrace_event_call *tp_event,
 int perf_trace_init(struct perf_event *p_event)
 {
 	struct ftrace_event_call *tp_event;
-	int event_id = p_event->attr.config;
+	u64 event_id = p_event->attr.config;
 	int ret = -EINVAL;
 
 	mutex_lock(&event_mutex);

Re: [patch] perf/trace properly use u64 to hold event_id

[Peter Zijlstra]

On Fri, Nov 15, 2013 at 12:39:45PM -0500, Vince Weaver wrote:
> 
> The 64-bit attr.config value for perf trace events was being copied into
> an "int" before doing a comparison, meaning the top 32 bits were
> being truncated.
> 
> As far as I can tell this didn't cause any errors, but it did mean
> it was possible to create valid aliases for all the tracepoint ids
> which I don't think was intended.  (For example, 0xffffffff00000018
> and 0x18 both enable the same tracepoint).
> 
> Signed-off-by: Vince Weaver <vincent.weaver@maine.edu>

Thanks!

[tip:perf/urgent] perf/trace: Properly use u64 to hold event_id

[tip-bot for Vince Weaver]

Commit-ID:  0022cedd4a7d8a87841351e2b018bb6794cf2e67
Gitweb:     http://git.kernel.org/tip/0022cedd4a7d8a87841351e2b018bb6794cf2e67
Author:     Vince Weaver <vincent.weaver@maine.edu>
AuthorDate: Fri, 15 Nov 2013 12:39:45 -0500
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 19 Nov 2013 16:57:44 +0100

perf/trace: Properly use u64 to hold event_id

The 64-bit attr.config value for perf trace events was being copied into
an "int" before doing a comparison, meaning the top 32 bits were
being truncated.

As far as I can tell this didn't cause any errors, but it did mean
it was possible to create valid aliases for all the tracepoint ids
which I don't think was intended.  (For example, 0xffffffff00000018
and 0x18 both enable the same tracepoint).

Signed-off-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1311151236100.11932@vincent-weaver-1.um.maine.edu
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/trace/trace_event_perf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index 630889f..e854f42 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -179,7 +179,7 @@ static int perf_trace_event_init(struct ftrace_event_call *tp_event,
 int perf_trace_init(struct perf_event *p_event)
 {
 	struct ftrace_event_call *tp_event;
-	int event_id = p_event->attr.config;
+	u64 event_id = p_event->attr.config;
 	int ret = -EINVAL;
 
 	mutex_lock(&event_mutex);