From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Sat, 9 Oct 2021 13:41:37 +0000 (+0200)
Subject: 4.4-stable patches
X-Git-Tag: v5.14.12~46
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=dca510b3e6172b3e73e719b3d96b6d453715032f;p=thirdparty%2Fkernel%2Fstable-queue.git

4.4-stable patches

added patches:
	usb-cdc-acm-fix-break-reporting.patch
	usb-cdc-acm-fix-racy-tty-buffer-accesses.patch
---

diff --git a/queue-4.4/series b/queue-4.4/series
index e69de29bb2d..fa71354d2ef 100644
--- a/queue-4.4/series
+++ b/queue-4.4/series
@@ -0,0 +1,2 @@
+usb-cdc-acm-fix-racy-tty-buffer-accesses.patch
+usb-cdc-acm-fix-break-reporting.patch
diff --git a/queue-4.4/usb-cdc-acm-fix-break-reporting.patch b/queue-4.4/usb-cdc-acm-fix-break-reporting.patch
new file mode 100644
index 00000000000..58ee89580af
--- /dev/null
+++ b/queue-4.4/usb-cdc-acm-fix-break-reporting.patch
@@ -0,0 +1,36 @@
+From 58fc1daa4d2e9789b9ffc880907c961ea7c062cc Mon Sep 17 00:00:00 2001
+From: Johan Hovold <johan@kernel.org>
+Date: Wed, 29 Sep 2021 11:09:37 +0200
+Subject: USB: cdc-acm: fix break reporting
+
+From: Johan Hovold <johan@kernel.org>
+
+commit 58fc1daa4d2e9789b9ffc880907c961ea7c062cc upstream.
+
+A recent change that started reporting break events forgot to push the
+event to the line discipline, which meant that a detected break would
+not be reported until further characters had been receive (the port
+could even have been closed and reopened in between).
+
+Fixes: 08dff274edda ("cdc-acm: fix BREAK rx code path adding necessary calls")
+Cc: stable@vger.kernel.org
+Acked-by: Oliver Neukum <oneukum@suse.com>
+Signed-off-by: Johan Hovold <johan@kernel.org>
+Link: https://lore.kernel.org/r/20210929090937.7410-3-johan@kernel.org
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/usb/class/cdc-acm.c |    3 +++
+ 1 file changed, 3 insertions(+)
+
+--- a/drivers/usb/class/cdc-acm.c
++++ b/drivers/usb/class/cdc-acm.c
+@@ -348,6 +348,9 @@ static void acm_ctrl_irq(struct urb *urb
+ 			acm->iocount.overrun++;
+ 		spin_unlock(&acm->read_lock);
+ 
++		if (newctrl & ACM_CTRL_BRK)
++			tty_flip_buffer_push(&acm->port);
++
+ 		if (difference)
+ 			wake_up_all(&acm->wioctl);
+ 
diff --git a/queue-4.4/usb-cdc-acm-fix-racy-tty-buffer-accesses.patch b/queue-4.4/usb-cdc-acm-fix-racy-tty-buffer-accesses.patch
new file mode 100644
index 00000000000..9e3b530ff9f
--- /dev/null
+++ b/queue-4.4/usb-cdc-acm-fix-racy-tty-buffer-accesses.patch
@@ -0,0 +1,53 @@
+From 65a205e6113506e69a503b61d97efec43fc10fd7 Mon Sep 17 00:00:00 2001
+From: Johan Hovold <johan@kernel.org>
+Date: Wed, 29 Sep 2021 11:09:36 +0200
+Subject: USB: cdc-acm: fix racy tty buffer accesses
+
+From: Johan Hovold <johan@kernel.org>
+
+commit 65a205e6113506e69a503b61d97efec43fc10fd7 upstream.
+
+A recent change that started reporting break events to the line
+discipline caused the tty-buffer insertions to no longer be serialised
+by inserting events also from the completion handler for the interrupt
+endpoint.
+
+Completion calls for distinct endpoints are not guaranteed to be
+serialised. For example, in case a host-controller driver uses
+bottom-half completion, the interrupt and bulk-in completion handlers
+can end up running in parallel on two CPUs (high-and low-prio tasklets,
+respectively) thereby breaking the tty layer's single producer
+assumption.
+
+Fix this by holding the read lock also when inserting characters from
+the bulk endpoint.
+
+Fixes: 08dff274edda ("cdc-acm: fix BREAK rx code path adding necessary calls")
+Cc: stable@vger.kernel.org
+Acked-by: Oliver Neukum <oneukum@suse.com>
+Signed-off-by: Johan Hovold <johan@kernel.org>
+Link: https://lore.kernel.org/r/20210929090937.7410-2-johan@kernel.org
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/usb/class/cdc-acm.c |    5 +++++
+ 1 file changed, 5 insertions(+)
+
+--- a/drivers/usb/class/cdc-acm.c
++++ b/drivers/usb/class/cdc-acm.c
+@@ -407,11 +407,16 @@ static int acm_submit_read_urbs(struct a
+ 
+ static void acm_process_read_urb(struct acm *acm, struct urb *urb)
+ {
++	unsigned long flags;
++
+ 	if (!urb->actual_length)
+ 		return;
+ 
++	spin_lock_irqsave(&acm->read_lock, flags);
+ 	tty_insert_flip_string(&acm->port, urb->transfer_buffer,
+ 			urb->actual_length);
++	spin_unlock_irqrestore(&acm->read_lock, flags);
++
+ 	tty_flip_buffer_push(&acm->port);
+ }
+