From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Mon, 7 Mar 2022 08:00:57 +0000 (+0100)
Subject: 4.19-stable patches
X-Git-Tag: v4.9.305~14
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=ec3b296ad86531aa52be2d1da993d6ec52c1e6a8;p=thirdparty%2Fkernel%2Fstable-queue.git

4.19-stable patches

added patches:
	net-dcb-disable-softirqs-in-dcbnl_flush_dev.patch
---

diff --git a/queue-4.19/net-dcb-disable-softirqs-in-dcbnl_flush_dev.patch b/queue-4.19/net-dcb-disable-softirqs-in-dcbnl_flush_dev.patch
new file mode 100644
index 00000000000..07c51a30480
--- /dev/null
+++ b/queue-4.19/net-dcb-disable-softirqs-in-dcbnl_flush_dev.patch
@@ -0,0 +1,57 @@
+From 10b6bb62ae1a49ee818fc479cf57b8900176773e Mon Sep 17 00:00:00 2001
+From: Vladimir Oltean <vladimir.oltean@nxp.com>
+Date: Wed, 2 Mar 2022 21:39:39 +0200
+Subject: net: dcb: disable softirqs in dcbnl_flush_dev()
+
+From: Vladimir Oltean <vladimir.oltean@nxp.com>
+
+commit 10b6bb62ae1a49ee818fc479cf57b8900176773e upstream.
+
+Ido Schimmel points out that since commit 52cff74eef5d ("dcbnl : Disable
+software interrupts before taking dcb_lock"), the DCB API can be called
+by drivers from softirq context.
+
+One such in-tree example is the chelsio cxgb4 driver:
+dcb_rpl
+-> cxgb4_dcb_handle_fw_update
+   -> dcb_ieee_setapp
+
+If the firmware for this driver happened to send an event which resulted
+in a call to dcb_ieee_setapp() at the exact same time as another
+DCB-enabled interface was unregistering on the same CPU, the softirq
+would deadlock, because the interrupted process was already holding the
+dcb_lock in dcbnl_flush_dev().
+
+Fix this unlikely event by using spin_lock_bh() in dcbnl_flush_dev() as
+in the rest of the dcbnl code.
+
+Fixes: 91b0383fef06 ("net: dcb: flush lingering app table entries for unregistered devices")
+Reported-by: Ido Schimmel <idosch@idosch.org>
+Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
+Link: https://lore.kernel.org/r/20220302193939.1368823-1-vladimir.oltean@nxp.com
+Signed-off-by: Jakub Kicinski <kuba@kernel.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ net/dcb/dcbnl.c |    4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+--- a/net/dcb/dcbnl.c
++++ b/net/dcb/dcbnl.c
+@@ -2058,7 +2058,7 @@ static void dcbnl_flush_dev(struct net_d
+ {
+ 	struct dcb_app_type *itr, *tmp;
+ 
+-	spin_lock(&dcb_lock);
++	spin_lock_bh(&dcb_lock);
+ 
+ 	list_for_each_entry_safe(itr, tmp, &dcb_app_list, list) {
+ 		if (itr->ifindex == dev->ifindex) {
+@@ -2067,7 +2067,7 @@ static void dcbnl_flush_dev(struct net_d
+ 		}
+ 	}
+ 
+-	spin_unlock(&dcb_lock);
++	spin_unlock_bh(&dcb_lock);
+ }
+ 
+ static int dcbnl_netdevice_event(struct notifier_block *nb,
diff --git a/queue-4.19/series b/queue-4.19/series
index 183e4993ef5..0a135444512 100644
--- a/queue-4.19/series
+++ b/queue-4.19/series
@@ -48,3 +48,4 @@ hid-add-mapping-for-key_all_applications.patch
 memfd-fix-f_seal_write-after-shmem-huge-page-allocated.patch
 tracing-histogram-fix-sorting-on-old-cpu-value.patch
 btrfs-add-missing-run-of-delayed-items-after-unlink-during-log-replay.patch
+net-dcb-disable-softirqs-in-dcbnl_flush_dev.patch