git: a03a5ac3ba76 - stable/13 - Add stop_all_proc_block(9)

The branch stable/13 has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=a03a5ac3ba761032ec50faf87d52198747562b65

commit a03a5ac3ba761032ec50faf87d52198747562b65
Author:     Konstantin Belousov <kib@FreeBSD.org>
AuthorDate: 2022-04-23 22:55:04 +0000
Commit:     Konstantin Belousov <kib@FreeBSD.org>
CommitDate: 2022-06-24 14:45:45 +0000

    Add stop_all_proc_block(9)
    
    (cherry picked from commit 2e7595ef2f53f6debec3c3d89bb9e0cd10394ed3)
---
 sys/kern/kern_proc.c | 19 +++++++++++++++++++
 sys/sys/proc.h       |  2 ++
 2 files changed, 21 insertions(+)

diff --git a/sys/kern/kern_proc.c b/sys/kern/kern_proc.c
index 063fe2eb1fe2..5faa5641c566 100644
--- a/sys/kern/kern_proc.c
+++ b/sys/kern/kern_proc.c
@@ -3319,6 +3319,21 @@ static SYSCTL_NODE(_kern_proc, KERN_PROC_SIGFASTBLK, sigfastblk, CTLFLAG_RD |
 	CTLFLAG_ANYBODY | CTLFLAG_MPSAFE, sysctl_kern_proc_sigfastblk,
 	"Thread sigfastblock address");
 
+static struct sx stop_all_proc_blocker;
+SX_SYSINIT(stop_all_proc_blocker, &stop_all_proc_blocker, "sapblk");
+
+void
+stop_all_proc_block(void)
+{
+	sx_xlock(&stop_all_proc_blocker);
+}
+
+void
+stop_all_proc_unblock(void)
+{
+	sx_xunlock(&stop_all_proc_blocker);
+}
+
 int allproc_gen;
 
 /*
@@ -3334,6 +3349,8 @@ stop_all_proc(void)
 	int r, gen;
 	bool restart, seen_stopped, seen_exiting, stopped_some;
 
+	stop_all_proc_block();
+
 	cp = curproc;
 allproc_loop:
 	sx_xlock(&allproc_lock);
@@ -3425,6 +3442,8 @@ again:
 			goto again;
 	}
 	sx_xunlock(&allproc_lock);
+
+	stop_all_proc_unblock();
 }
 
 /* #define	TOTAL_STOP_DEBUG	1 */
diff --git a/sys/sys/proc.h b/sys/sys/proc.h
index 38675248b22d..3db7ce620176 100644
--- a/sys/sys/proc.h
+++ b/sys/sys/proc.h
@@ -1205,6 +1205,8 @@ void	thread_unlink(struct thread *td);
 void	thread_unsuspend(struct proc *p);
 void	thread_wait(struct proc *p);
 
+void	stop_all_proc_block(void);
+void	stop_all_proc_unblock(void);
 void	stop_all_proc(void);
 void	resume_all_proc(void);