e1000: fix data race between tx_ring->next_to_clean

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

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]))