perf maps: Lookup maps in both intitial mountns and inner mountns.

If a process is in a mountns and has symbols in /tmp/perf-<pid>.map,
look first in the namespace using the tgid for the pidns that the
process might be in.  If the map isn't found there, try looking in the
mountns where perf is running, and use the tgid that's appropriate for
perf's pid namespace.  If all else fails, use the original pid.

This allows us to locate a symbol map file in the mount namespace, if it
was generated there.  However, we also try the tool's /tmp in case it's
there instead.

Signed-off-by: Krister Johansen <kjlx@templeofstupid.com>
Tested-by: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas-Mich Richter <tmricht@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1499305693-1599-3-git-send-email-kjlx@templeofstupid.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 19 insertions, 4 deletions

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index 5dc60ca5a294..bdaa0a4edc17 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -146,11 +146,13 @@ void map__init(struct map *map, enum map_type type,
 }
 
 struct map *map__new(struct machine *machine, u64 start, u64 len,
-		     u64 pgoff, u32 pid, u32 d_maj, u32 d_min, u64 ino,
+		     u64 pgoff, u32 d_maj, u32 d_min, u64 ino,
 		     u64 ino_gen, u32 prot, u32 flags, char *filename,
 		     enum map_type type, struct thread *thread)
 {
 	struct map *map = malloc(sizeof(*map));
+	struct nsinfo *nsi = NULL;
+	struct nsinfo *nnsi;
 
 	if (map != NULL) {
 		char newfilename[PATH_MAX];
@@ -168,9 +170,11 @@ struct map *map__new(struct machine *machine, u64 start, u64 len,
 		map->ino_generation = ino_gen;
 		map->prot = prot;
 		map->flags = flags;
+		nsi = nsinfo__get(thread->nsinfo);
 
-		if ((anon || no_dso) && type == MAP__FUNCTION) {
-			snprintf(newfilename, sizeof(newfilename), "/tmp/perf-%d.map", pid);
+		if ((anon || no_dso) && nsi && type == MAP__FUNCTION) {
+			snprintf(newfilename, sizeof(newfilename),
+				 "/tmp/perf-%d.map", nsi->pid);
 			filename = newfilename;
 		}
 
@@ -180,6 +184,16 @@ struct map *map__new(struct machine *machine, u64 start, u64 len,
 		}
 
 		if (vdso) {
+			/* The vdso maps are always on the host and not the
+			 * container.  Ensure that we don't use setns to look
+			 * them up.
+			 */
+			nnsi = nsinfo__copy(nsi);
+			if (nnsi) {
+				nsinfo__put(nsi);
+				nnsi->need_setns = false;
+				nsi = nnsi;
+			}
 			pgoff = 0;
 			dso = machine__findnew_vdso(machine, thread);
 		} else
@@ -201,11 +215,12 @@ struct map *map__new(struct machine *machine, u64 start, u64 len,
 			if (type != MAP__FUNCTION)
 				dso__set_loaded(dso, map->type);
 		}
-		dso->nsinfo = nsinfo__get(thread->nsinfo);
+		dso->nsinfo = nsi;
 		dso__put(dso);
 	}
 	return map;
 out_delete:
+	nsinfo__put(nsi);
 	free(map);
 	return NULL;
 }