Most architectures currently check this in their get_wchan() implementation
(ARC doesn't hence this patch). However doing this in core code shows
the semantics better so move the check one level up (eventually remove
the boiler-plate code from arches)
Signed-off-by: Vineet Gupta <vgupta@xxxxxxxxxxxx>
# tools/perf/arch/arc/util/
---
fs/proc/array.c | 4 +++-
fs/proc/base.c | 6 ++++--
2 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/fs/proc/array.c b/fs/proc/array.c
index 65ec2029fa80..081fade5a361 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -519,8 +519,10 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
unlock_task_sighand(task, &flags);
}
- if (permitted && (!whole || num_threads < 2))
+ if (task != current && task->state != TASK_RUNNING &&
+ permitted && (!whole || num_threads < 2))
wchan = get_wchan(task);
+
if (!whole) {
min_flt = task->min_flt;
maj_flt = task->maj_flt;
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 0f707003dda5..abd7ec6324c5 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -385,13 +385,15 @@ static const struct file_operations proc_pid_cmdline_ops = {
static int proc_pid_wchan(struct seq_file *m, struct pid_namespace *ns,
struct pid *pid, struct task_struct *task)
{
- unsigned long wchan;
+ unsigned long wchan = 0;
char symname[KSYM_NAME_LEN];
if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
goto print0;
- wchan = get_wchan(task);
+ if (task != current && task->state != TASK_RUNNING)
+ wchan = get_wchan(task);
+
if (wchan && !lookup_symbol_name(wchan, symname)) {
seq_puts(m, symname);
return 0;
--
2.25.1
