From: Tianyu Yuan <tianyu.yuan@xxxxxxxxxxxx>
When CONFIG_PROVE_LOCKING and CONFIG_PROVE_RCU are enabled, using
OVS with vf reprs on bridge will lead to following log in dmesg:
'''
.../nfp/flower/main.c:269 suspicious rcu_dereference_check() usage!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1
no locks held by swapper/15/0.
......
Call Trace:
<IRQ>
dump_stack_lvl+0x8c/0xa0
lockdep_rcu_suspicious+0x118/0x1a0
nfp_flower_dev_get+0xc1/0x240 [nfp]
nfp_nfd3_rx+0x419/0xb90 [nfp]
? validate_chain+0x640/0x1880
nfp_nfd3_poll+0x3e/0x180 [nfp]
__napi_poll+0x28/0x1d0
net_rx_action+0x2bd/0x3c0
? _raw_spin_unlock_irqrestore+0x42/0x70
__do_softirq+0xc3/0x3c6
irq_exit_rcu+0xeb/0x130
common_interrupt+0xb9/0xd0
</IRQ>
<TASK>
......
</TASK>
'''
This debug log is caused by missing of rcu_read_lock()/unlock().
In previous patch rcu_read_lock/unlock are removed while they are
still needed when calling rcu_dereference() in nfp_app_dev_get().
Fixes: d5789621b658 ("nfp: Remove rcu_read_lock() around XDP program invocation")
CC: stable@xxxxxxxxxxxxxxx
Signed-off-by: Tianyu Yuan <tianyu.yuan@xxxxxxxxxxxx>
Acked-by: Simon Horman <simon.horman@xxxxxxxxxxxx>
Signed-off-by: Louis Peens <louis.peens@xxxxxxxxxxxx>
---
drivers/net/ethernet/netronome/nfp/nfd3/dp.c | 4 ++--
drivers/net/ethernet/netronome/nfp/nfd3/xsk.c | 2 +-
drivers/net/ethernet/netronome/nfp/nfdk/dp.c | 4 ++--
drivers/net/ethernet/netronome/nfp/nfp_app.h | 16 ++++++++++++++++
4 files changed, 21 insertions(+), 5 deletions(-)
diff --git a/drivers/net/ethernet/netronome/nfp/nfd3/dp.c b/drivers/net/ethernet/netronome/nfp/nfd3/dp.c
index 0cc026b0aefd..3e5a84370d8a 100644
--- a/drivers/net/ethernet/netronome/nfp/nfd3/dp.c
+++ b/drivers/net/ethernet/netronome/nfp/nfd3/dp.c
@@ -1058,8 +1058,8 @@ static int nfp_nfd3_rx(struct nfp_net_rx_ring *rx_ring, int budget)
struct nfp_net *nn;
nn = netdev_priv(dp->netdev);
- netdev = nfp_app_dev_get(nn->app, meta.portid,
- &redir_egress);
+ netdev = nfp_app_dev_get_locked(nn->app, meta.portid,
+ &redir_egress);
if (unlikely(!netdev)) {
nfp_nfd3_rx_drop(dp, r_vec, rx_ring, rxbuf,
NULL);
diff --git a/drivers/net/ethernet/netronome/nfp/nfd3/xsk.c b/drivers/net/ethernet/netronome/nfp/nfd3/xsk.c
index 5d9db8c2a5b4..6ec5b0d430ea 100644
--- a/drivers/net/ethernet/netronome/nfp/nfd3/xsk.c
+++ b/drivers/net/ethernet/netronome/nfp/nfd3/xsk.c
@@ -71,7 +71,7 @@ static void nfp_nfd3_xsk_rx_skb(struct nfp_net_rx_ring *rx_ring,
} else {
struct nfp_net *nn = netdev_priv(dp->netdev);
- netdev = nfp_app_dev_get(nn->app, meta->portid, NULL);
+ netdev = nfp_app_dev_get_locked(nn->app, meta->portid, NULL);
if (unlikely(!netdev)) {
nfp_net_xsk_rx_drop(r_vec, xrxbuf);
return;
diff --git a/drivers/net/ethernet/netronome/nfp/nfdk/dp.c b/drivers/net/ethernet/netronome/nfp/nfdk/dp.c
index 33b6d74adb4b..0ac68985d289 100644
--- a/drivers/net/ethernet/netronome/nfp/nfdk/dp.c
+++ b/drivers/net/ethernet/netronome/nfp/nfdk/dp.c
@@ -1177,8 +1177,8 @@ static int nfp_nfdk_rx(struct nfp_net_rx_ring *rx_ring, int budget)
struct nfp_net *nn;
nn = netdev_priv(dp->netdev);
- netdev = nfp_app_dev_get(nn->app, meta.portid,
- &redir_egress);
+ netdev = nfp_app_dev_get_locked(nn->app, meta.portid,
+ &redir_egress);
if (unlikely(!netdev)) {
nfp_nfdk_rx_drop(dp, r_vec, rx_ring, rxbuf,
NULL);
diff --git a/drivers/net/ethernet/netronome/nfp/nfp_app.h b/drivers/net/ethernet/netronome/nfp/nfp_app.h
index 90707346a4ef..639bb1a6349b 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_app.h
+++ b/drivers/net/ethernet/netronome/nfp/nfp_app.h
@@ -417,6 +417,22 @@ struct net_device *nfp_app_dev_get(struct nfp_app *app, u32 id,
return app->type->dev_get(app, id, redir_egress);
}
+static inline
+struct net_device *nfp_app_dev_get_locked(struct nfp_app *app, u32 id,
+ bool *redir_egress)
+{
+ struct net_device *dev;
+
+ if (unlikely(!app || !app->type->dev_get))
+ return NULL;
+
+ rcu_read_lock();
+ dev = app->type->dev_get(app, id, redir_egress);
+ rcu_read_unlock();
+
+ return dev;
+}
+
struct nfp_app *nfp_app_from_netdev(struct net_device *netdev);
u64 *nfp_app_port_get_stats(struct nfp_port *port, u64 *data);
--
2.34.1
