perf report: Handle vDSO symbols properly

We were not looking up vDSO symbols properly, because they
are in the kallsyms but are user-mode entries.

Pass negative addresses to the kernel dso object, this
way we resolve them properly:

     0.05%  [kernel]: vread_tsc

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: John Kacur <jkacur@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/Documentation/perf_counter/builtin-report.c b/Documentation/perf_counter/builtin-report.c
index a8d390596d8d39bd469c366dff82c9583e1ecaad..0f88d9ebb34a3c304252d9d2c52c51ea4e896946 100644 (file)
--- a/Documentation/perf_counter/builtin-report.c
+++ b/Documentation/perf_counter/builtin-report.c
@@ -728,6 +728,8 @@ more:
                        event->ip.pid,
                        (void *)(long)ip);
 
+               dprintf(" ... thread: %s:%d\n", thread->comm, thread->pid);
+
                if (thread == NULL) {
                        fprintf(stderr, "problem processing %d event, skipping it.\n",
                                event->header.type);
@@ -740,6 +742,8 @@ more:
 
                        dso = kernel_dso;
 
+                       dprintf(" ...... dso: %s\n", dso->name);
+
                } else if (event->header.misc & PERF_EVENT_MISC_USER) {
 
                        show = SHOW_USER;
@@ -749,11 +753,22 @@ more:
                        if (map != NULL) {
                                dso = map->dso;
                                ip -= map->start + map->pgoff;
+                       } else {
+                               /*
+                                * If this is outside of all known maps,
+                                * and is a negative address, try to look it
+                                * up in the kernel dso, as it might be a
+                                * vsyscall (which executes in user-mode):
+                                */
+                               if ((long long)ip < 0)
+                                       dso = kernel_dso;
                        }
+                       dprintf(" ...... dso: %s\n", dso ? dso->name : "<not found>");
 
                } else {
                        show = SHOW_HV;
                        level = 'H';
+                       dprintf(" ...... dso: [hypervisor]\n");
                }
 
                if (show & show_mask) {