kernel: add a kernel_wait helper

Add a helper that waits for a pid and stores the status in the passed in kernel pointer. Use it to fix the usage of kernel_wait4 in call_usermodehelper_exec_sync that only happens to work due to the implicit set_fs(KERNEL_DS) for kernel threads.

Christoph Hellwig committed 6 years ago

Commit 8043fc11 parent f48ff833 files · +21 −25Browse files

Showing the changes to include/linux (1 of 3 files). Show all

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include/linux/sched/task.h+1−0

@@ -88,6 +88,7 @@ struct task_struct *fork_idle(int); · 87 unmodified lines
88	struct mm_struct *copy_init_mm(void);	88	struct mm_struct *copy_init_mm(void);
89	extern pid_t kernel_thread(int (fn)(void ), void *arg, unsigned long flags);	89	extern pid_t kernel_thread(int (fn)(void ), void *arg, unsigned long flags);
90	extern long kernel_wait4(pid_t, int __user , int, struct rusage );	90	extern long kernel_wait4(pid_t, int __user , int, struct rusage );
		91	int kernel_wait(pid_t pid, int *stat);
91		92
92	extern void free_task(struct task_struct *tsk);	93	extern void free_task(struct task_struct *tsk);
93		94