Merge tag 'perf-core-for-mingo-4.18-20180516' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core

Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:

- Add '-e intel_pt//u' test to the 'parse-events' 'perf test' entry,
  to help avoiding regressions in the events parser such as one
  that caused a revert in v4.17-rc (Arnaldo Carvalho de Melo)

- Fix NULL return handling in bpf__prepare_load() (YueHaibing)

- Warn about 'perf buildid-cache --purge-all' failures (Ravi Bangoria)

- Add infrastructure to help in writing eBPF C programs to be used
  with '-e name.c' type events in tools such as 'record' and 'trace',
  with headers for common constructs and an examples directory that
  will get populated as we add more such helpers and the 'perf bpf'
  branch that Jiri Olsa has been working on (Arnaldo Carvalho de Melo)

- Handle uncore event aliases in small groups properly (Kan Liang)

- Use the "_stest" symbol to identify the kernel map when loading kcore (Adrian Hunter)

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/kernel/module.c b/kernel/module.c
index ce8066b88178..c9bea7f2b43e 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3517,6 +3517,11 @@ static noinline int do_init_module(struct module *mod)
 	 * walking this with preempt disabled.  In all the failure paths, we
 	 * call synchronize_sched(), but we don't want to slow down the success
 	 * path, so use actual RCU here.
+	 * Note that module_alloc() on most architectures creates W+X page
+	 * mappings which won't be cleaned up until do_free_init() runs.  Any
+	 * code such as mark_rodata_ro() which depends on those mappings to
+	 * be cleaned up needs to sync with the queued work - ie
+	 * rcu_barrier_sched()
 	 */
 	call_rcu_sched(&freeinit->rcu, do_free_init);
 	mutex_unlock(&module_mutex);