| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.10 096/104] net: watchdog: hold device global xmit lock during tx disable | Date | Mon, 15 Feb 2021 16:27:49 +0100 |
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From: Edwin Peer <edwin.peer@broadcom.com>
commit 3aa6bce9af0e25b735c9c1263739a5639a336ae8 upstream.
Prevent netif_tx_disable() running concurrently with dev_watchdog() by taking the device global xmit lock. Otherwise, the recommended:
netif_carrier_off(dev); netif_tx_disable(dev);
driver shutdown sequence can happen after the watchdog has already checked carrier, resulting in possible false alarms. This is because netif_tx_lock() only sets the frozen bit without maintaining the locks on the individual queues.
Fixes: c3f26a269c24 ("netdev: Fix lockdep warnings in multiqueue configurations.") Signed-off-by: Edwin Peer <edwin.peer@broadcom.com> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- include/linux/netdevice.h | 2 ++ 1 file changed, 2 insertions(+)
--- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -4313,6 +4313,7 @@ static inline void netif_tx_disable(stru local_bh_disable(); cpu = smp_processor_id(); + spin_lock(&dev->tx_global_lock); for (i = 0; i < dev->num_tx_queues; i++) { struct netdev_queue *txq = netdev_get_tx_queue(dev, i); @@ -4320,6 +4321,7 @@ static inline void netif_tx_disable(stru netif_tx_stop_queue(txq); __netif_tx_unlock(txq); } + spin_unlock(&dev->tx_global_lock); local_bh_enable(); }
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