git: 05b84d640274 - stable/14 - uart: fix sleeping while holding mutex in uart_tty_detach()

The branch stable/14 has been updated by kevans:

URL: https://cgit.FreeBSD.org/src/commit/?id=05b84d64027451b298c56025eed11bf047be234d

commit 05b84d64027451b298c56025eed11bf047be234d
Author:     Abdelkader Boudih <freebsd@seuros.com>
AuthorDate: 2026-02-03 03:21:43 +0000
Commit:     Kyle Evans <kevans@FreeBSD.org>
CommitDate: 2026-04-12 13:43:43 +0000

    uart: fix sleeping while holding mutex in uart_tty_detach()
    
    Move swi_remove() call before acquiring the tty lock. swi_remove() calls
    intr_event_remove_handler() which may sleep via msleep(), causing a lock
    order violation when called with the tty mutex held.
    
    The software interrupt handler removal operates on the interrupt event
    structure independently and does not require the tty lock. This matches
    the pattern used in other drivers such as tcp_hpts.c where swi_remove()
    is called without holding other locks.
    
    Reviewed by:    imp, kevans
    
    (cherry picked from commit ed3a2469a71e0ef48cf8e636c35e64a011756da3)
---
 sys/dev/uart/uart_tty.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sys/dev/uart/uart_tty.c b/sys/dev/uart/uart_tty.c
index 736c756322a4..5a86c7325429 100644
--- a/sys/dev/uart/uart_tty.c
+++ b/sys/dev/uart/uart_tty.c
@@ -448,8 +448,9 @@ uart_tty_detach(struct uart_softc *sc)
 
 	tp = sc->sc_u.u_tty.tp;
 
-	tty_lock(tp);
 	swi_remove(sc->sc_softih);
+
+	tty_lock(tp);
 	tty_rel_gone(tp);
 
 	return (0);