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

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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
1 changed files with 30 additions and 13 deletions
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43
sys/kern/kern_shutdown.c
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@ -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>
@ -276,6 +277,28 @@ sys_reboot(struct thread *td, struct reboot_args *uap)
return (error);
}
static void
shutdown_nice_task_fn(void *arg, int pending __unused)
{
int howto;
howto = (uintptr_t)arg;
/* Send a signal to init(8) and have it shutdown the world. */
PROC_LOCK(initproc);
if (howto & RB_POWEROFF)
kern_psignal(initproc, SIGUSR2);
else if (howto & RB_POWERCYCLE)
kern_psignal(initproc, SIGWINCH);
else if (howto & RB_HALT)
kern_psignal(initproc, SIGUSR1);
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
*/
@ -283,20 +306,14 @@ void
shutdown_nice(int howto)
{
if (initproc != NULL) {
/* Send a signal to init(8) and have it shutdown the world. */
PROC_LOCK(initproc);
if (howto & RB_POWEROFF)
kern_psignal(initproc, SIGUSR2);
else if (howto & RB_POWERCYCLE)
kern_psignal(initproc, SIGWINCH);
else if (howto & RB_HALT)
kern_psignal(initproc, SIGUSR1);
else
kern_psignal(initproc, SIGINT);
PROC_UNLOCK(initproc);
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);
}
}