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authorArnaldo Carvalho de Melo <acme@redhat.com>2015-03-20 17:46:53 -0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2015-03-21 14:53:36 -0300
commitf208bd8df08d0659ecd9e09e992c79aab26cddfa (patch)
tree94c8bff840892df70218232788a397c754e45249 /tools/perf/builtin-trace.c
parente6c76d620379fd65fc0310aee1785ff7b1b10236 (diff)
downloadlinux-f208bd8df08d0659ecd9e09e992c79aab26cddfa.tar.gz
perf trace: Handle legacy syscalls tracepoints
Currently the code skips the first field with the expectation that it is 'nr'. But older kernels do not have the 'nr' field: field:int nr; offset:8; size:4; signed:1; Change perf-trace to drop the field if it exists after parsing the format file. This fixes the off-by-one problem with older kernels (e.g., RHEL6). e.g, perf-trace shows this for write: 1.515 ( 0.006 ms): dd/4245 write(buf: 2</dev/pts/0>, count: 140733837536224 ) = 26 where 2 is really the fd, the huge number is really the buf address, etc. With this patch you get the more appropriate: 1.813 ( 0.003 ms): dd/6330 write(fd: 2</dev/pts/0>, buf: 0x7fff22fc81f0, count: 25) = 25 Based-on-a-patch-by: David Ahern <dsahern@gmail.com> Acked-by: David Ahern <dsahern@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-gvpdave4u2yq2jnzbcdznpvf@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/builtin-trace.c')
-rw-r--r--tools/perf/builtin-trace.c18
1 files changed, 14 insertions, 4 deletions
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 6af6bcec930e..001c6ae9a1b1 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -1135,6 +1135,8 @@ static struct syscall_fmt *syscall_fmt__find(const char *name)
struct syscall {
struct event_format *tp_format;
+ int nr_args;
+ struct format_field *args;
const char *name;
bool filtered;
bool is_exit;
@@ -1442,14 +1444,14 @@ static int syscall__set_arg_fmts(struct syscall *sc)
struct format_field *field;
int idx = 0;
- sc->arg_scnprintf = calloc(sc->tp_format->format.nr_fields - 1, sizeof(void *));
+ sc->arg_scnprintf = calloc(sc->nr_args, sizeof(void *));
if (sc->arg_scnprintf == NULL)
return -1;
if (sc->fmt)
sc->arg_parm = sc->fmt->arg_parm;
- for (field = sc->tp_format->format.fields->next; field; field = field->next) {
+ for (field = sc->args; field; field = field->next) {
if (sc->fmt && sc->fmt->arg_scnprintf[idx])
sc->arg_scnprintf[idx] = sc->fmt->arg_scnprintf[idx];
else if (field->flags & FIELD_IS_POINTER)
@@ -1515,6 +1517,14 @@ static int trace__read_syscall_info(struct trace *trace, int id)
if (sc->tp_format == NULL)
return -1;
+ sc->args = sc->tp_format->format.fields;
+ sc->nr_args = sc->tp_format->format.nr_fields;
+ /* drop nr field - not relevant here; does not exist on older kernels */
+ if (sc->args && strcmp(sc->args->name, "nr") == 0) {
+ sc->args = sc->args->next;
+ --sc->nr_args;
+ }
+
sc->is_exit = !strcmp(name, "exit_group") || !strcmp(name, "exit");
return syscall__set_arg_fmts(sc);
@@ -1537,7 +1547,7 @@ static size_t syscall__scnprintf_args(struct syscall *sc, char *bf, size_t size,
unsigned char *p;
unsigned long val;
- if (sc->tp_format != NULL) {
+ if (sc->args != NULL) {
struct format_field *field;
u8 bit = 1;
struct syscall_arg arg = {
@@ -1547,7 +1557,7 @@ static size_t syscall__scnprintf_args(struct syscall *sc, char *bf, size_t size,
.thread = thread,
};
- for (field = sc->tp_format->format.fields->next; field;
+ for (field = sc->args; field;
field = field->next, ++arg.idx, bit <<= 1) {
if (arg.mask & bit)
continue;