4.9-stable patches

added patches:
	tty-n_gsm-fix-proper-link-termination-after-failed-open.patch

diff --git a/queue-4.9/series b/queue-4.9/series
index 6b35690f601e478b4e2494c9d4776c5214744e05..f49057c814dc4f893d6ed2e2f921a29512026296 100644 (file)
--- a/queue-4.9/series
+++ b/queue-4.9/series
@@ -24,3 +24,4 @@ usb-serial-option-add-telit-le910r1-compositions.patch
 usb-dwc3-gadget-let-the-interrupt-handler-disable-bottom-halves.patch
 xhci-prevent-futile-urb-re-submissions-due-to-incorrect-return-value.patch
 tty-n_gsm-fix-encoding-of-control-signal-octet-bit-dv.patch
+tty-n_gsm-fix-proper-link-termination-after-failed-open.patch

diff --git a/queue-4.9/tty-n_gsm-fix-proper-link-termination-after-failed-open.patch b/queue-4.9/tty-n_gsm-fix-proper-link-termination-after-failed-open.patch
new file mode 100644 (file)
index 0000000..fce3375
--- /dev/null
+++ b/queue-4.9/tty-n_gsm-fix-proper-link-termination-after-failed-open.patch
@@ -0,0 +1,38 @@
+From e3b7468f082d106459e86e8dc6fb9bdd65553433 Mon Sep 17 00:00:00 2001
+From: "daniel.starke@siemens.com" <daniel.starke@siemens.com>
+Date: Thu, 17 Feb 2022 23:31:19 -0800
+Subject: tty: n_gsm: fix proper link termination after failed open
+
+From: daniel.starke@siemens.com <daniel.starke@siemens.com>
+
+commit e3b7468f082d106459e86e8dc6fb9bdd65553433 upstream.
+
+Trying to open a DLCI by sending a SABM frame may fail with a timeout.
+The link is closed on the initiator side without informing the responder
+about this event. The responder assumes the link is open after sending a
+UA frame to answer the SABM frame. The link gets stuck in a half open
+state.
+
+This patch fixes this by initiating the proper link termination procedure
+after link setup timeout instead of silently closing it down.
+
+Fixes: e1eaea46bb40 ("tty: n_gsm line discipline")
+Cc: stable@vger.kernel.org
+Signed-off-by: Daniel Starke <daniel.starke@siemens.com>
+Link: https://lore.kernel.org/r/20220218073123.2121-3-daniel.starke@siemens.com
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/tty/n_gsm.c |    2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+--- a/drivers/tty/n_gsm.c
++++ b/drivers/tty/n_gsm.c
+@@ -1506,7 +1506,7 @@ static void gsm_dlci_t1(unsigned long da
+                       dlci->mode = DLCI_MODE_ADM;
+                       gsm_dlci_open(dlci);
+               } else {
+-                      gsm_dlci_close(dlci);
++                      gsm_dlci_begin_close(dlci); /* prevent half open link */
+               }
+ 
+               break;