Messages in this thread Patch in this message | | | From | Brian Robbins <> | Subject | [PATCH v2] perf inject jit: Ignore memfd and anonymous mmap events if jitdump present | Date | Fri, 5 Aug 2022 15:06:45 -0700 |
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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> --- tools/perf/util/jitdump.c | 9 +++++++-- 1 file 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; -- 2.25.1
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