git: 52ea025eba6c - stable/13 - kthread_add(): do not allow to attach the thread to a dead or dying process

The branch stable/13 has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=52ea025eba6c4b9cf560f0dc90ed6c49846637ef

commit 52ea025eba6c4b9cf560f0dc90ed6c49846637ef
Author:     Konstantin Belousov <kib@FreeBSD.org>
AuthorDate: 2023-09-05 10:54:36 +0000
Commit:     Konstantin Belousov <kib@FreeBSD.org>
CommitDate: 2023-09-09 08:27:32 +0000

    kthread_add(): do not allow to attach the thread to a dead or dying process
    
    (cherry picked from commit 96362992330894787a4485f0adc5e867879c5893)
---
 sys/kern/kern_kthread.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sys/kern/kern_kthread.c b/sys/kern/kern_kthread.c
index 5e32aea1f56d..6f7fd8b3d555 100644
--- a/sys/kern/kern_kthread.c
+++ b/sys/kern/kern_kthread.c
@@ -281,6 +281,10 @@ kthread_add1(void (*func)(void *), void *arg, struct proc *p,
 		return (ENOMEM);
 
 	PROC_LOCK(p);
+	if (p->p_state == PRS_ZOMBIE || (p->p_flag2 & P2_WEXIT) != 0) {
+		PROC_UNLOCK(p);
+		return (ESRCH);
+	}
 	oldtd = FIRST_THREAD_IN_PROC(p);
 
 	bzero(&newtd->td_startzero,