[PATCH] perf: fix extern struct definitions

[PATCH] perf: fix extern struct definitions

[Stephane Eranian]

Both python_scripting_ops and perl_scripting_ops have two global definitions.
One in trace-event-scripting.c and one in their respective scripting-engine
modules.

The issue is that depending on the linker order one definition or the other
is chosen. One is uninitialized (bss), while the other is initialized. If
the uninitialized version is chosen, then perf does not function properly.

This patch fixes this by adding the extern prefix to the definitions in
trace-event-scripting.c. 

Signed-off-by: Stephane Eranian <eranian@google.com>

diff --git a/tools/perf/util/trace-event-scripting.c b/tools/perf/util/trace-event-scripting.c
index 7ea983a..f7af2fc 100644
--- a/tools/perf/util/trace-event-scripting.c
+++ b/tools/perf/util/trace-event-scripting.c
@@ -97,7 +97,7 @@ void setup_python_scripting(void)
 	register_python_scripting(&python_scripting_unsupported_ops);
 }
 #else
-struct scripting_ops python_scripting_ops;
+extern struct scripting_ops python_scripting_ops;
 
 void setup_python_scripting(void)
 {
@@ -158,7 +158,7 @@ void setup_perl_scripting(void)
 	register_perl_scripting(&perl_scripting_unsupported_ops);
 }
 #else
-struct scripting_ops perl_scripting_ops;
+extern struct scripting_ops perl_scripting_ops;
 
 void setup_perl_scripting(void)
 {

Re: [PATCH] perf: fix extern struct definitions

[Arnaldo Carvalho de Melo]

Em Tue, Sep 21, 2010 at 12:45:01AM +0200, Stephane Eranian escreveu:
> Both python_scripting_ops and perl_scripting_ops have two global definitions.
> One in trace-event-scripting.c and one in their respective scripting-engine
> modules.
> 
> The issue is that depending on the linker order one definition or the other
> is chosen. One is uninitialized (bss), while the other is initialized. If
> the uninitialized version is chosen, then perf does not function properly.
> 
> This patch fixes this by adding the extern prefix to the definitions in
> trace-event-scripting.c. 
> 
> Signed-off-by: Stephane Eranian <eranian@google.com>

Thanks, applying to perf/urgent,

- Arnaldo

[tip:perf/core] perf trace scripting: Fix extern struct definitions

[tip-bot for Stephane Eranian]

Commit-ID:  0f940cb7d970f4fd569bb5f9f49774422f2ccbee
Gitweb:     http://git.kernel.org/tip/0f940cb7d970f4fd569bb5f9f49774422f2ccbee
Author:     Stephane Eranian <eranian@google.com>
AuthorDate: Tue, 21 Sep 2010 00:45:01 +0200
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Mon, 4 Oct 2010 12:24:51 -0300

perf trace scripting: Fix extern struct definitions

Both python_scripting_ops and perl_scripting_ops have two global definitions.
One in trace-event-scripting.c and one in their respective scripting-engine
modules.

The issue is that depending on the linker order one definition or the other
is chosen. One is uninitialized (bss), while the other is initialized. If
the uninitialized version is chosen, then perf does not function properly.

This patch fixes this by adding the extern prefix to the definitions in
trace-event-scripting.c.

Cc: David S. Miller <davem@davemloft.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robert Richter <robert.richter@amd.com>
LKML-Reference: <4c97e41a.078fd80a.7a8b.3cc9@mx.google.com>
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/trace-event-scripting.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/trace-event-scripting.c b/tools/perf/util/trace-event-scripting.c
index 7ea983a..f7af2fc 100644
--- a/tools/perf/util/trace-event-scripting.c
+++ b/tools/perf/util/trace-event-scripting.c
@@ -97,7 +97,7 @@ void setup_python_scripting(void)
 	register_python_scripting(&python_scripting_unsupported_ops);
 }
 #else
-struct scripting_ops python_scripting_ops;
+extern struct scripting_ops python_scripting_ops;
 
 void setup_python_scripting(void)
 {
@@ -158,7 +158,7 @@ void setup_perl_scripting(void)
 	register_perl_scripting(&perl_scripting_unsupported_ops);
 }
 #else
-struct scripting_ops perl_scripting_ops;
+extern struct scripting_ops perl_scripting_ops;
 
 void setup_perl_scripting(void)
 {