diff options
| -rw-r--r-- | kernel/pid.c | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/kernel/pid.c b/kernel/pid.c index de0bf2f8d18b..c1d940fbd314 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -678,7 +678,26 @@ static struct file *__pidfd_fget(struct task_struct *task, int fd) up_read(&task->signal->exec_update_lock); - return file ?: ERR_PTR(-EBADF); + if (!file) { + /* + * It is possible that the target thread is exiting; it can be + * either: + * 1. before exit_signals(), which gives a real fd + * 2. before exit_files() takes the task_lock() gives a real fd + * 3. after exit_files() releases task_lock(), ->files is NULL; + * this has PF_EXITING, since it was set in exit_signals(), + * __pidfd_fget() returns EBADF. + * In case 3 we get EBADF, but that really means ESRCH, since + * the task is currently exiting and has freed its files + * struct, so we fix it up. + */ + if (task->flags & PF_EXITING) + file = ERR_PTR(-ESRCH); + else + file = ERR_PTR(-EBADF); + } + + return file; } static int pidfd_getfd(struct pid *pid, int fd) |