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e1000: fix data race between tx_ring->next_to_clean

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e1000_clean_tx_irq cleans buffers and sets tx_ring->next_to_clean,
then e1000_xmit_frame reuses the cleaned buffers. But there are no
memory barriers when buffers gets recycled, so the recycled buffers
can be corrupted.

Use smp_store_release to update tx_ring->next_to_clean and
smp_load_acquire to read tx_ring->next_to_clean to properly
hand off buffers from e1000_clean_tx_irq to e1000_xmit_frame.

The data race was found with KernelThreadSanitizer (KTSAN).

Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
This commit is contained in:
Dmitriy Vyukov 2015-09-08 10:52:44 +02:00 committed by Jeff Kirsher
parent 18f7ce5412
commit 9eab46b7cb
2 changed files with 9 additions and 3 deletions
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7
drivers/net/ethernet/intel/e1000/e1000.h
View File

@ -213,8 +213,11 @@ struct e1000_rx_ring {
};
#define E1000_DESC_UNUSED(R) \
((((R)->next_to_clean > (R)->next_to_use) \
? 0 : (R)->count) + (R)->next_to_clean - (R)->next_to_use - 1)
({ \
unsigned int clean = smp_load_acquire(&(R)->next_to_clean); \
unsigned int use = READ_ONCE((R)->next_to_use); \
(clean > use ? 0 : (R)->count) + clean - use - 1; \
})
#define E1000_RX_DESC_EXT(R, i) \
(&(((union e1000_rx_desc_extended *)((R).desc))[i]))

5
drivers/net/ethernet/intel/e1000/e1000_main.c
View File

@ -3876,7 +3876,10 @@ static bool e1000_clean_tx_irq(struct e1000_adapter *adapter,
eop_desc = E1000_TX_DESC(*tx_ring, eop);
}
tx_ring->next_to_clean = i;
/* Synchronize with E1000_DESC_UNUSED called from e1000_xmit_frame,
* which will reuse the cleaned buffers.
*/
smp_store_release(&tx_ring->next_to_clean, i);
netdev_completed_queue(netdev, pkts_compl, bytes_compl);