perf inject jit: Ignore memfd and anonymous mmap events if jitdump present

Some processes store jitted code in memfd mappings to avoid having rwx
mappings.  These processes map the code with a writeable mapping and a
read-execute mapping.  They write the code using the writeable mapping
and then unmap the writeable mapping.  All subsequent execution is
through the read-execute mapping.

perf inject --jit ignores //anon* mappings for each process where a
jitdump is present because it expects to inject mmap events for each
jitted code range, and said jitted code ranges will overlap with the
//anon* mappings.

Ignore /memfd: and [anon:* mappings so that jitted code contained in
/memfd: and [anon:* mappings is treated the same way as jitted code
contained in //anon* mappings.

Signed-off-by: Brian Robbins <[email protected]>
Acked-by: Ian Rogers <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

1 files changed, 7 insertions, 2 deletions

diff --git a/tools/perf/util/jitdump.c b/tools/perf/util/jitdump.c
index a23255773c60..4e6632203704 100644
--- a/tools/perf/util/jitdump.c
+++ b/tools/perf/util/jitdump.c
@@ -845,8 +845,13 @@ jit_process(struct perf_session *session,
 	if (jit_detect(filename, pid, nsi)) {
 		nsinfo__put(nsi);
 
-		// Strip //anon* mmaps if we processed a jitdump for this pid
-		if (jit_has_pid(machine, pid) && (strncmp(filename, "//anon", 6) == 0))
+		/*
+		 * Strip //anon*, [anon:* and /memfd:* mmaps if we processed a jitdump for this pid
+		 */
+		if (jit_has_pid(machine, pid) &&
+			((strncmp(filename, "//anon", 6) == 0) ||
+			 (strncmp(filename, "[anon:", 6) == 0) ||
+			 (strncmp(filename, "/memfd:", 7) == 0)))
 			return 1;
 
 		return 0;