git: 7c1c0e94363d - main - rpc: Improve socket locking in svc_vc_accept()

The branch main has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=7c1c0e94363db09af0c260d9292160cdd2230f23

commit 7c1c0e94363db09af0c260d9292160cdd2230f23
Author:     Mark Johnston <markj@FreeBSD.org>
AuthorDate: 2026-02-12 14:00:43 +0000
Commit:     Mark Johnston <markj@FreeBSD.org>
CommitDate: 2026-02-12 14:00:43 +0000

    rpc: Improve socket locking in svc_vc_accept()
    
    so_state modifications must be synchronized by the socket lock.  For the
    listening socket this probably doesn't matter but for the child socket I
    think it's possible that this unlocked update clobbers a state
    transition if the nascent connection is being disconnected for some
    reason.
    
    Also fix the line which potentially clears SS_NBIO in the listening
    socket.
    
    It is unclear whether this code is used at all.
    
    Reviewed by:    glebius
    MFC after:      1 week
    Differential Revision:  https://reviews.freebsd.org/D55247
---
 sys/rpc/svc_vc.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/sys/rpc/svc_vc.c b/sys/rpc/svc_vc.c
index 7e30582c59e0..848109704ad0 100644
--- a/sys/rpc/svc_vc.c
+++ b/sys/rpc/svc_vc.c
@@ -389,12 +389,15 @@ svc_vc_accept(struct socket *head, struct socket **sop)
 	SOLISTEN_LOCK(head);
 	nbio = head->so_state & SS_NBIO;
 	head->so_state |= SS_NBIO;
-	error = solisten_dequeue(head, &so, 0);
-	head->so_state &= (nbio & ~SS_NBIO);
+	error = solisten_dequeue(head, &so, nbio ? SOCK_NONBLOCK : 0);
+	if (nbio == 0) {
+		SOLISTEN_LOCK(head);
+		head->so_state &= ~SS_NBIO;
+		SOLISTEN_UNLOCK(head);
+	}
 	if (error)
 		goto done;
 
-	so->so_state |= nbio;
 	*sop = so;
 
 	/* connection has been removed from the listen queue */