git: 8da1c3715139 - stable/14 - reboot: Avoid unlocking Giant if the scheduler is stopped

From: Mark Johnston <markj_at_FreeBSD.org>
Date: Tue, 07 Nov 2023 00:23:50 UTC
The branch stable/14 has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=8da1c3715139ecfbda9159c766507e0f80212e92

commit 8da1c3715139ecfbda9159c766507e0f80212e92
Author:     Mark Johnston <markj@FreeBSD.org>
AuthorDate: 2023-11-04 14:48:58 +0000
Commit:     Mark Johnston <markj@FreeBSD.org>
CommitDate: 2023-11-07 00:23:38 +0000

    reboot: Avoid unlocking Giant if the scheduler is stopped
    
    When the scheduler is stopped, mtx_unlock() turns into a no-op, so the
    loop
    
        while (mtx_owned(&Giant))
                mtx_unlock(&Giant);
    
    runs forever if the calling thread has Giant locked.
    
    Reviewed by:    mhorne
    MFC after:      3 days
    Differential Revision:  https://reviews.freebsd.org/D42460
    
    (cherry picked from commit deacab756026f86515781944a9e0271e8db9f86b)
---
 sys/kern/kern_shutdown.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sys/kern/kern_shutdown.c b/sys/kern/kern_shutdown.c
index e0eff6dbec01..19920d30357f 100644
--- a/sys/kern/kern_shutdown.c
+++ b/sys/kern/kern_shutdown.c
@@ -471,7 +471,7 @@ kern_reboot(int howto)
 	 * deadlock than to lock against code that won't ever
 	 * continue.
 	 */
-	while (mtx_owned(&Giant))
+	while (!SCHEDULER_STOPPED() && mtx_owned(&Giant))
 		mtx_unlock(&Giant);
 
 #if defined(SMP)