Messages in this thread |  | | From | Jia-Ju Bai <> | Subject | [REPORT] net: 3com: 3c59x: Possible data races | Date | Wed, 3 Oct 2018 21:52:14 +0800 |
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****** Possible race0 ****** CPU0: vortex_boomerang_interrupt line 2510: spin_lock_irqsave() _boomerang_interrupt line 2432: vp->tx_skbuff[entry] [READ] line 2433: vp->tx_skbuff[entry] [READ] line 2453: vp->tx_skbuff[entry] = NULL [WRITE]
CPU1: boomerang_start_xmit line 2145: vp->tx_skbuff[entry] = skb [WRITE]
As for vp->tx_skbuff[entry], the WRITE and READ operations in CPU0 are performed with holding a spinlock, but the WRITE operation in CPU1 is performed without holding this spinlock, so there may exist data races.
****** Possible race1 ****** CPU0: vortex_boomerang_interrupt line 2510: spin_lock_irqsave() _boomerang_interrupt line 2421: vp->dirty_tx = dirty_tx [WRITE]
CPU1: boomerang_start_xmit line 2137: vp->dirty_tx [READ]
As for vp->dirty_tx, the WRITE operation in CPU0 is performed with holding a spinlock, but the READ operation in CPU1 is performed without holding this spinlock, so there may exist a data race.
****** Possible race2 ****** CPU0: vortex_boomerang_interrupt line 2510: spin_lock_irqsave() _boomerang_interrupt line 2381: vp->handling_irq = 1 [WRITE] line 2498: vp->handling_irq = 0 [WRITE]
CPU1: boomerang_start_xmit line 2134: vp->handling_irq [READ]
As for vp->handling_irq, the WRITE operations in CPU0 are performed with holding a spinlock, but the READ operation in CPU1 is performed without holding this spinlock, so there may exist data races.
****** Possible race3 ****** CPU0: vortex_boomerang_interrupt line 2510: spin_lock_irqsave() _boomerang_interrupt boomerang_rx line 2669: skb->ip_summed = ... [WRITE]
CPU1: boomerang_start_xmit line 2149: skb->ip_summed [READ]
As for skb->ip_summed, the WRITE operation in CPU0 is performed with holding a spinlock, but the READ operation in CPU1 is performed without holding this spinlock, so there may exist data races.
These possible races are detected by a runtime testing. A possible fix of these races is protecting the code in boomerang_start_xmit() using the spinlock in vortex_boomerang_interrupt(). But I am not sure whether this fix is correct, so I only report these races.
Best wishes, Jia-Ju Bai
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