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perf namespace: Protect reading thread's namespace 

It seems that the current code lacks holding the namespace lock in
thread__namespaces().  Otherwise it can see inconsistent results.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Hari Bathini <hbathini@linux.vnet.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Krister Johansen <kjlx@templeofstupid.com>
Link: http://lkml.kernel.org/r/20190522053250.207156-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Namhyung Kim 2019-05-22 14:32:48 +09:00 committed by Arnaldo Carvalho de Melo
parent 9903c64f0f
commit 6584140ba9
1 changed files with 13 additions and 2 deletions
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15
tools/perf/util/thread.c
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@ -133,7 +133,7 @@ void thread__put(struct thread *thread)
} }
} }
struct namespaces *thread__namespaces(const struct thread *thread) static struct namespaces *__thread__namespaces(const struct thread *thread)
{ {
if (list_empty(&thread->namespaces_list)) if (list_empty(&thread->namespaces_list))
return NULL; return NULL;
@ -141,10 +141,21 @@ struct namespaces *thread__namespaces(const struct thread *thread)
return list_first_entry(&thread->namespaces_list, struct namespaces, list); return list_first_entry(&thread->namespaces_list, struct namespaces, list);
} }
struct namespaces *thread__namespaces(const struct thread *thread)
{
struct namespaces *ns;
down_read((struct rw_semaphore *)&thread->namespaces_lock);
ns = __thread__namespaces(thread);
up_read((struct rw_semaphore *)&thread->namespaces_lock);
return ns;
}
static int __thread__set_namespaces(struct thread *thread, u64 timestamp, static int __thread__set_namespaces(struct thread *thread, u64 timestamp,
struct namespaces_event *event) struct namespaces_event *event)
{ {
struct namespaces *new, *curr = thread__namespaces(thread); struct namespaces *new, *curr = __thread__namespaces(thread);
new = namespaces__new(event); new = namespaces__new(event);
if (!new) if (!new)