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perf tools: Fix jump label always changing during tracing 

Intel PT decoding walks the object code to reconstruct the trace.  A
jump label change during tracing causes decoding errors.

The "Enable close-on-exec flag on perf file descriptor" patch caused
there to be always a jump label change.

It was found that using a per-cpu context instead of a per-thread
context for the probe of the close-on-exec feature, made the problem go
away.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1406035081-14301-2-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Adrian Hunter 2014-07-22 16:17:10 +03:00 committed by Arnaldo Carvalho de Melo
parent a6f6ae99f1
commit deaff8b659
1 changed files with 7 additions and 2 deletions
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9
tools/perf/util/cloexec.c
View File

@ -1,3 +1,4 @@
#include <sched.h>
#include "util.h"
#include "../perf.h"
#include "cloexec.h"
@ -14,9 +15,13 @@ static int perf_flag_probe(void)
};
int fd;
int err;
int cpu = sched_getcpu();
if (cpu < 0)
cpu = 0;
/* check cloexec flag */
fd = sys_perf_event_open(&attr, 0, -1, -1,
fd = sys_perf_event_open(&attr, -1, cpu, -1,
PERF_FLAG_FD_CLOEXEC);
err = errno;
@ -30,7 +35,7 @@ static int perf_flag_probe(void)
err, strerror(err));
/* not supported, confirm error related to PERF_FLAG_FD_CLOEXEC */
fd = sys_perf_event_open(&attr, 0, -1, -1, 0);
fd = sys_perf_event_open(&attr, -1, cpu, -1, 0);
err = errno;
if (WARN_ONCE(fd < 0,