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0851133bb5
The device reset procedure, stop_gfar()/startup_gfar(), has concurrency issues. "Kernel access of bad area" oopses show up during Tx timeout device reset or other reset cases (like changing MTU) that happen while the interface still has traffic. The oopses happen in start_xmit and clean_tx_ring when accessing tx_queue-> tx_skbuff which is NULL. The race comes from de-allocating the tx_skbuff while transmission and napi processing are still active. Though the Tx queues get temoprarily stopped when Tx timeout occurs, they get re-enabled as a result of Tx congestion handling inside the napi context (see clean_tx_ring()). Not disabling the napi during reset is also a bug, because clean_tx_ring() will try to access tx_skbuff while it is being de-alloc'ed and re-alloc'ed. To fix this, stop_gfar() needs to disable napi processing after stopping the Tx queues. However, in order to prevent clean_tx_ring() to re-enable the Tx queue before the napi gets disabled, the device state DOWN has been introduced. It prevents the Tx congestion management from re-enabling the de-congested Tx queue while the device is brought down. An additional locking state, RESETTING, has been introduced to prevent simultaneous resets or to prevent configuring the device while it is resetting. The bogus 'rxlock's (for each Rx queue) have been removed since their purpose is not justified, as they don't prevent nor are suited to prevent device reset/reconfig races (such as this one). Signed-off-by: Claudiu Manoil <claudiu.manoil@freescale.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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| Kconfig | ||
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| Makefile | ||
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