From: Jiri Pirko <jiri@xxxxxxxxxx>
[ Upstream commit e93c9378e33f68b61ea9318580d841caa22fb9ea ]
The commit 565b4824c39f ("devlink: change port event netdev notifier
from per-net to global") changed original per-net notifier to be
per-devlink instance. That fixed the issue of non-receiving events
of netdev uninit if that moved to a different namespace.
That worked fine in -net tree.
However, later on when commit ee75f1fc44dd ("net/mlx5e: Create
separate devlink instance for ethernet auxiliary device") and
commit 72ed5d5624af ("net/mlx5: Suspend auxiliary devices only in
case of PCI device suspend") were merged, a deadlock was introduced
when removing a namespace with devlink instance with another nested
instance.
Here there is the bad flow example resulting in deadlock with mlx5:
net_cleanup_work -> cleanup_net (takes down_read(&pernet_ops_rwsem) ->
devlink_pernet_pre_exit() -> devlink_reload() ->
mlx5_devlink_reload_down() -> mlx5_unload_one_devl_locked() ->
mlx5_detach_device() -> del_adev() -> mlx5e_remove() ->
mlx5e_destroy_devlink() -> devlink_free() ->
unregister_netdevice_notifier() (takes down_write(&pernet_ops_rwsem)
Steps to reproduce:
$ modprobe mlx5_core
$ ip netns add ns1
$ devlink dev reload pci/0000:08:00.0 netns ns1
$ ip netns del ns1
Resolve this by converting the notifier from per-devlink instance to
a static one registered during init phase and leaving it registered
forever. Use this notifier for all devlink port instances created
later on.
Note what a tree needs this fix only in case all of the cited fixes
commits are present.
Reported-by: Moshe Shemesh <moshe@xxxxxxxxxx>
Fixes: 565b4824c39f ("devlink: change port event netdev notifier from per-net to global")
Fixes: ee75f1fc44dd ("net/mlx5e: Create separate devlink instance for ethernet auxiliary device")
Fixes: 72ed5d5624af ("net/mlx5: Suspend auxiliary devices only in case of PCI device suspend")
Signed-off-by: Jiri Pirko <jiri@xxxxxxxxxx>
Reviewed-by: Simon Horman <simon.horman@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230510144621.932017-1-jiri@xxxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/devlink/core.c | 16 +++++++---------
net/devlink/devl_internal.h | 1 -
net/devlink/leftover.c | 5 ++---
3 files changed, 9 insertions(+), 13 deletions(-)
diff --git a/net/devlink/core.c b/net/devlink/core.c
index 777b091ef74df..0e58eee44bdb2 100644
--- a/net/devlink/core.c
+++ b/net/devlink/core.c
@@ -204,11 +204,6 @@ struct devlink *devlink_alloc_ns(const struct devlink_ops *ops,
if (ret < 0)
goto err_xa_alloc;
- devlink->netdevice_nb.notifier_call = devlink_port_netdevice_event;
- ret = register_netdevice_notifier(&devlink->netdevice_nb);
- if (ret)
- goto err_register_netdevice_notifier;
-
devlink->dev = dev;
devlink->ops = ops;
xa_init_flags(&devlink->ports, XA_FLAGS_ALLOC);
@@ -233,8 +228,6 @@ struct devlink *devlink_alloc_ns(const struct devlink_ops *ops,
return devlink;
-err_register_netdevice_notifier:
- xa_erase(&devlinks, devlink->index);
err_xa_alloc:
kfree(devlink);
return NULL;
@@ -266,8 +259,6 @@ void devlink_free(struct devlink *devlink)
xa_destroy(&devlink->params);
xa_destroy(&devlink->ports);
- WARN_ON_ONCE(unregister_netdevice_notifier(&devlink->netdevice_nb));
-
xa_erase(&devlinks, devlink->index);
devlink_put(devlink);
@@ -303,6 +294,10 @@ static struct pernet_operations devlink_pernet_ops __net_initdata = {
.pre_exit = devlink_pernet_pre_exit,
};
+static struct notifier_block devlink_port_netdevice_nb __net_initdata = {
+ .notifier_call = devlink_port_netdevice_event,
+};
+
static int __init devlink_init(void)
{
int err;
@@ -311,6 +306,9 @@ static int __init devlink_init(void)
if (err)
goto out;
err = register_pernet_subsys(&devlink_pernet_ops);
+ if (err)
+ goto out;
+ err = register_netdevice_notifier(&devlink_port_netdevice_nb);
out:
WARN_ON(err);
diff --git a/net/devlink/devl_internal.h b/net/devlink/devl_internal.h
index e133f423294a2..62921b2eb0d3f 100644
--- a/net/devlink/devl_internal.h
+++ b/net/devlink/devl_internal.h
@@ -50,7 +50,6 @@ struct devlink {
u8 reload_failed:1;
refcount_t refcount;
struct rcu_work rwork;
- struct notifier_block netdevice_nb;
char priv[] __aligned(NETDEV_ALIGN);
};
diff --git a/net/devlink/leftover.c b/net/devlink/leftover.c
index dffca2f9bfa7f..cd02549680767 100644
--- a/net/devlink/leftover.c
+++ b/net/devlink/leftover.c
@@ -7073,10 +7073,9 @@ int devlink_port_netdevice_event(struct notifier_block *nb,
struct devlink_port *devlink_port = netdev->devlink_port;
struct devlink *devlink;
- devlink = container_of(nb, struct devlink, netdevice_nb);
-
- if (!devlink_port || devlink_port->devlink != devlink)
+ if (!devlink_port)
return NOTIFY_OK;
+ devlink = devlink_port->devlink;
switch (event) {
case NETDEV_POST_INIT:
--
2.39.2
