Merge tag 'perf-core-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core

Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:

User visible changes:

  - Warn if given uprobe event accesses memory on older kernel (Masami Hiramatsu)

  - 'perf record' Documentation fixes (Namhyung Kim)

  - Report unsupported events properly in 'perf stat' (Suzuki K. Poulose)

Infrastructure changes:

  - Avoid FORK after COMM when synthesizing records for pre-existing threads (Arnaldo Carvalho de Melo)

  - Reference count struct thread (Arnaldo Carvalho de Melo)

  - Don't keep the session around in 'perf sched', thread refcounting removes that need (Arnaldo Carvalho de Melo)

  - Initialize cpu set in pthread_attr_setaffinity_np() feature test (Adrian Hunter)

  - Only include tsc file for x86 (David Ahern)

  - Compare JOBS to 0 after grep (David Ahern)

  - Improve feature detection messages (Ingo Molnar)

  - Revert "perf: Remove the extra validity check on nr_pages" (Kan Liang)

  - Remove bias offset to find probe point by address (Masami Hiramatsu)

  - Fix build error on ARCH=i386/x86_64/sparc64 (Namhyung Kim)

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 23 insertions, 0 deletions

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 7c0e765fa2e3..1c570c2fa7cc 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -2199,6 +2199,27 @@ static int get_new_event_name(char *buf, size_t len, const char *base,
         return ret;
 }
 
+/* Warn if the current kernel's uprobe implementation is old */
+static void warn_uprobe_event_compat(struct probe_trace_event *tev)
+{
+        int i;
+        char *buf = synthesize_probe_trace_command(tev);
+
+        /* Old uprobe event doesn't support memory dereference */
+        if (!tev->uprobes || tev->nargs == 0 || !buf)
+                goto out;
+
+        for (i = 0; i < tev->nargs; i++)
+                if (strglobmatch(tev->args[i].value, "[$@+-]*")) {
+                        pr_warning("Please upgrade your kernel to at least "
+                                   "3.14 to have access to feature %s\n",
+                                   tev->args[i].value);
+                        break;
+                }
+out:
+        free(buf);
+}
+
 static int __add_probe_trace_events(struct perf_probe_event *pev,
                                      struct probe_trace_event *tevs,
                                      int ntevs, bool allow_suffix)
@@ -2295,6 +2316,8 @@ static int __add_probe_trace_events(struct perf_probe_event *pev,
                  */
                 allow_suffix = true;
         }
+        if (ret == -EINVAL && pev->uprobes)
+                warn_uprobe_event_compat(tev);
 
         /* Note that it is possible to skip all events because of blacklist */
         if (ret >= 0 && tev->event) {