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 <brianrob@linux.microsoft.com>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220805220645.95855-1-brianrob@linux.microsoft.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/jitdump.c b/tools/perf/util/jitdump.c
index a232557..4e66322 100644 (file)
--- 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;