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[34.32.214.5]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-b734fd80d27sm403941966b.40.2025.11.14.07.02.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 14 Nov 2025 07:02:04 -0800 (PST) From: "=?UTF-8?q?=C5=81ukasz=20Bartosik?=" X-Google-Original-From: =?UTF-8?q?=C5=81ukasz=20Bartosik?= To: Mathias Nyman , Greg Kroah-Hartman Cc: linux-usb@vger.kernel.org, =?UTF-8?q?=C5=81ukasz=20Bartosik?= , stable@vger.kernel.org Subject: [PATCH v1] xhci: dbgtty: fix device unregister Date: Fri, 14 Nov 2025 15:01:47 +0000 Message-ID: <20251114150147.584150-1-ukaszb@google.com> X-Mailer: git-send-email 2.52.0.rc1.455.g30608eb744-goog Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Łukasz Bartosik When DbC is disconnected then xhci_dbc_tty_unregister_device() is called. However if there is any user space process blocked on write to DbC terminal device then it will never be signalled and thus stay blocked indifinitely. This fix adds a tty_hangup() call in xhci_dbc_tty_unregister_device(). The tty_hangup() wakes up any blocked writers and causes subsequent write attempts to DbC terminal device to fail. Cc: stable@vger.kernel.org Fixes: dfba2174dc42 ("usb: xhci: Add DbC support in xHCI driver") Signed-off-by: Łukasz Bartosik --- drivers/usb/host/xhci-dbgtty.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/usb/host/xhci-dbgtty.c b/drivers/usb/host/xhci-dbgtty.c index d894081d8d15..6ea31af576c7 100644 --- a/drivers/usb/host/xhci-dbgtty.c +++ b/drivers/usb/host/xhci-dbgtty.c @@ -535,6 +535,13 @@ static void xhci_dbc_tty_unregister_device(struct xhci_dbc *dbc) if (!port->registered) return; + /* + * Hang up the TTY. This wakes up any blocked + * writers and causes subsequent writes to fail. + */ + if (port->port.tty) + tty_hangup(port->port.tty); + tty_unregister_device(dbc_tty_driver, port->minor); xhci_dbc_tty_exit_port(port); port->registered = false; -- 2.52.0.rc1.455.g30608eb744-goog