Messages in this thread Patch in this message | | | Date | Wed, 07 Oct 2009 22:15:55 -0700 (PDT) | Subject | Re: [BUG] znet.c sleeping function called from invalid context | From | David Miller <> |
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From: Mike Frysinger <vapier.adi@gmail.com> Date: Wed, 7 Oct 2009 14:44:45 -0400
> On Wed, Oct 7, 2009 at 14:47, Alexander Strakh wrote: >> KERNEL_VERSION: 2.6.31 >> DESCRIBE: >> Driver drivers/net/znet.c might sleep in atomic context, because it calls >> free_dma under claim_dma_lock: >> >> .drivers/net/znet.c: >> 168 static int znet_request_resources (struct net_device *dev) >> ... >> 189 flags = claim_dma_lock(); >> 190 free_dma (znet->tx_dma); >> 191 release_dma_lock (flags); >> ... >> >> Path to might_sleep macro from znet_request_resources: >> 1. znet_request_resources calls free_dma at >> arch/blackfin/kernel/bfin_dma_5xx.c:181 >> 2. free_dma calls arch/blackfin/kernel/bfin_dma_5xx.c:195 > > i dont think we need the dmalock mutex. it's only used to protect > read/writes to .chan_status, and that should be atomic already. > -mike
I'm checking in the obvious fix to net-2.6, thanks for the report:
znet: Don't claim DMA lock around free_dma() calls.
It's not necessary and it's illegal too.
Reported-by: Alexander Strakh <strakh@ispras.ru> Signed-off-by: David S. Miller <davem@davemloft.net> --- drivers/net/znet.c | 8 -------- 1 files changed, 0 insertions(+), 8 deletions(-)
diff --git a/drivers/net/znet.c b/drivers/net/znet.c index a0384b6..b423473 100644 --- a/drivers/net/znet.c +++ b/drivers/net/znet.c @@ -169,7 +169,6 @@ static void znet_tx_timeout (struct net_device *dev); static int znet_request_resources (struct net_device *dev) { struct znet_private *znet = netdev_priv(dev); - unsigned long flags; if (request_irq (dev->irq, &znet_interrupt, 0, "ZNet", dev)) goto failed; @@ -187,13 +186,9 @@ static int znet_request_resources (struct net_device *dev) free_sia: release_region (znet->sia_base, znet->sia_size); free_tx_dma: - flags = claim_dma_lock(); free_dma (znet->tx_dma); - release_dma_lock (flags); free_rx_dma: - flags = claim_dma_lock(); free_dma (znet->rx_dma); - release_dma_lock (flags); free_irq: free_irq (dev->irq, dev); failed: @@ -203,14 +198,11 @@ static int znet_request_resources (struct net_device *dev) static void znet_release_resources (struct net_device *dev) { struct znet_private *znet = netdev_priv(dev); - unsigned long flags; release_region (znet->sia_base, znet->sia_size); release_region (dev->base_addr, znet->io_size); - flags = claim_dma_lock(); free_dma (znet->tx_dma); free_dma (znet->rx_dma); - release_dma_lock (flags); free_irq (dev->irq, dev); } -- 1.6.4.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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