proc: fix coredump vs read /proc/*/stat race

[mirror_ubuntu-bionic-kernel.git] / fs / proc / array.c

diff --git a/fs/proc/array.c b/fs/proc/array.c
index 79375fc115d277f9336e8aa75b0c1846dc093fc9..d67a72dcb92c47865177c2243231572f040c3cf6 100644 (file)
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -430,8 +430,11 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
                 * safe because the task has stopped executing permanently.
                 */
                if (permitted && (task->flags & PF_DUMPCORE)) {
-                       eip = KSTK_EIP(task);
-                       esp = KSTK_ESP(task);
+                       if (try_get_task_stack(task)) {
+                               eip = KSTK_EIP(task);
+                               esp = KSTK_ESP(task);
+                               put_task_stack(task);
+                       }
                }
        }