Do not send signals to init directly from shutdown_nice(9), do it from

the task context.

shutdown_nice() is used from the fast interrupt handlers, mostly for
console drivers, where we cannot lock blockable locks.  Schedule the
task in the fast queue to send the signal from the proper context.

Reviewed by:	imp
Discussed with:	bde
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
This commit is contained in:
Konstantin Belousov 2018-03-22 20:47:25 +00:00
parent 54f30ad961
commit c398200721

View File

@ -72,6 +72,7 @@ __FBSDID("$FreeBSD$");
#include <sys/smp.h>
#include <sys/sysctl.h>
#include <sys/sysproto.h>
#include <sys/taskqueue.h>
#include <sys/vnode.h>
#include <sys/watchdog.h>
@ -276,14 +277,12 @@ sys_reboot(struct thread *td, struct reboot_args *uap)
return (error);
}
/*
* Called by events that want to shut down.. e.g <CTL><ALT><DEL> on a PC
*/
void
shutdown_nice(int howto)
static void
shutdown_nice_task_fn(void *arg, int pending __unused)
{
int howto;
if (initproc != NULL) {
howto = (uintptr_t)arg;
/* Send a signal to init(8) and have it shutdown the world. */
PROC_LOCK(initproc);
if (howto & RB_POWEROFF)
@ -295,8 +294,26 @@ shutdown_nice(int howto)
else
kern_psignal(initproc, SIGINT);
PROC_UNLOCK(initproc);
}
static struct task shutdown_nice_task = TASK_INITIALIZER(0,
&shutdown_nice_task_fn, NULL);
/*
* Called by events that want to shut down.. e.g <CTL><ALT><DEL> on a PC
*/
void
shutdown_nice(int howto)
{
if (initproc != NULL && !SCHEDULER_STOPPED()) {
shutdown_nice_task.ta_context = (void *)(uintptr_t)howto;
taskqueue_enqueue(taskqueue_fast, &shutdown_nice_task);
} else {
/* No init(8) running, so simply reboot. */
/*
* No init(8) running, or scheduler would not allow it
* to run, so simply reboot.
*/
kern_reboot(howto | RB_NOSYNC);
}
}