1 files changed, 13 insertions, 3 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index c9e3f650f23c..08e3eccf9a12 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2706,9 +2706,16 @@ static int do_io_accounting(struct task_struct *task, char *buffer, int whole)
 {
         struct task_io_accounting acct = task->ioac;
         unsigned long flags;
+        int result;
 
-        if (!ptrace_may_access(task, PTRACE_MODE_READ))
-                return -EACCES;
+        result = mutex_lock_killable(&task->signal->cred_guard_mutex);
+        if (result)
+                return result;
+
+        if (!ptrace_may_access(task, PTRACE_MODE_READ)) {
+                result = -EACCES;
+                goto out_unlock;
+        }
 
         if (whole && lock_task_sighand(task, &flags)) {
                 struct task_struct *t = task;
@@ -2719,7 +2726,7 @@ static int do_io_accounting(struct task_struct *task, char *buffer, int whole)
 
                 unlock_task_sighand(task, &flags);
         }
-        return sprintf(buffer,
+        result = sprintf(buffer,
                         "rchar: %llu\n"
                         "wchar: %llu\n"
                         "syscr: %llu\n"
@@ -2734,6 +2741,9 @@ static int do_io_accounting(struct task_struct *task, char *buffer, int whole)
                         (unsigned long long)acct.read_bytes,
                         (unsigned long long)acct.write_bytes,
                         (unsigned long long)acct.cancelled_write_bytes);
+out_unlock:
+        mutex_unlock(&task->signal->cred_guard_mutex);
+        return result;
 }
 
 static int proc_tid_io_accounting(struct task_struct *task, char *buffer)