From 0b0e2ff10356e7e2ffd66ecdd6eee69a2f03449b Mon Sep 17 00:00:00 2001
From: Vladimir Oltean <vladimir.oltean@nxp.com>
Date: Mon, 28 Feb 2022 16:17:15 +0200
Subject: net: dsa: restore error path of dsa_tree_change_tag_proto
When the DSA_NOTIFIER_TAG_PROTO returns an error, the user space process
which initiated the protocol change exits the kernel processing while
still holding the rtnl_mutex. So any other process attempting to lock
the rtnl_mutex would deadlock after such event.
The error handling of DSA_NOTIFIER_TAG_PROTO was inadvertently changed
by the blamed commit, introducing this regression. We must still call
rtnl_unlock(), and we must still call DSA_NOTIFIER_TAG_PROTO for the old
protocol. The latter is due to the limiting design of notifier chains
for cross-chip operations, which don't have a built-in error recovery
mechanism - we should look into using notifier_call_chain_robust for that.
Fixes: dc452a471dba ("net: dsa: introduce tagger-owned storage for private and shared data")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20220228141715.146485-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
net/dsa/dsa2.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
(limited to 'net/dsa/dsa2.c')
diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
index dcad3100b164..209496996cdf 100644
--- a/net/dsa/dsa2.c
+++ b/net/dsa/dsa2.c
@@ -1261,7 +1261,7 @@ int dsa_tree_change_tag_proto(struct dsa_switch_tree *dst,
info.tag_ops = tag_ops;
err = dsa_tree_notify(dst, DSA_NOTIFIER_TAG_PROTO, &info);
if (err)
- return err;
+ goto out_unlock;
err = dsa_tree_bind_tag_proto(dst, tag_ops);
if (err)
--
cgit v1.2.3
From e1bec7fa1cee311a6d3fb9161037c7675904134d Mon Sep 17 00:00:00 2001
From: Vladimir Oltean <vladimir.oltean@nxp.com>
Date: Thu, 3 Mar 2022 17:42:49 +0200
Subject: net: dsa: make dsa_tree_change_tag_proto actually unwind the tag
proto change
The blamed commit said one thing but did another. It explains that we
should restore the "return err" to the original "goto out_unwind_tagger",
but instead it replaced it with "goto out_unlock".
When DSA_NOTIFIER_TAG_PROTO fails after the first switch of a
multi-switch tree, the switches would end up not using the same tagging
protocol.
Fixes: 0b0e2ff10356 ("net: dsa: restore error path of dsa_tree_change_tag_proto")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20220303154249.1854436-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
net/dsa/dsa2.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
(limited to 'net/dsa/dsa2.c')
diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
index 209496996cdf..b4e67758e104 100644
--- a/net/dsa/dsa2.c
+++ b/net/dsa/dsa2.c
@@ -1261,7 +1261,7 @@ int dsa_tree_change_tag_proto(struct dsa_switch_tree *dst,
info.tag_ops = tag_ops;
err = dsa_tree_notify(dst, DSA_NOTIFIER_TAG_PROTO, &info);
if (err)
- goto out_unlock;
+ goto out_unwind_tagger;
err = dsa_tree_bind_tag_proto(dst, tag_ops);
if (err)
--
cgit v1.2.3
From afb3cc1a397d77771f342691b7e6b032a234d7f2 Mon Sep 17 00:00:00 2001
From: Vladimir Oltean <vladimir.oltean@nxp.com>
Date: Thu, 3 Mar 2022 16:08:40 +0200
Subject: net: dsa: unlock the rtnl_mutex when dsa_master_setup() fails
After the blamed commit, dsa_tree_setup_master() may exit without
calling rtnl_unlock(), fix that.
Fixes: c146f9bc195a ("net: dsa: hold rtnl_mutex when calling dsa_master_{setup,teardown}")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/dsa/dsa2.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
(limited to 'net/dsa/dsa2.c')
diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
index b4e67758e104..074e4a69a728 100644
--- a/net/dsa/dsa2.c
+++ b/net/dsa/dsa2.c
@@ -1058,7 +1058,7 @@ static int dsa_tree_setup_switches(struct dsa_switch_tree *dst)
static int dsa_tree_setup_master(struct dsa_switch_tree *dst)
{
struct dsa_port *dp;
- int err;
+ int err = 0;
rtnl_lock();
@@ -1066,13 +1066,13 @@ static int dsa_tree_setup_master(struct dsa_switch_tree *dst)
if (dsa_port_is_cpu(dp)) {
err = dsa_master_setup(dp->master, dp);
if (err)
- return err;
+ break;
}
}
rtnl_unlock();
- return 0;
+ return err;
}
static void dsa_tree_teardown_master(struct dsa_switch_tree *dst)
--
cgit v1.2.3