From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [BUG] znet.c sleeping function called from invalid context Date: Wed, 07 Oct 2009 22:15:55 -0700 (PDT) Message-ID: <20091007.221555.71697986.davem@davemloft.net> References: <200910071847.38163.strakh@ispras.ru> <8bd0f97a0910071144k1d0bf30bv60656181edae8af7@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Cc: netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, strakh-ufN2psIa012HXe+LvDLADg@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, michael.hennerich-OyLXuOCK7orQT0dZR+AlfA@public.gmane.org, uclinux-dist-devel-ZG0+EudsQA8dtHy/vicBwGD2FQJk+8+b@public.gmane.org To: vapier.adi-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org Return-path: In-Reply-To: <8bd0f97a0910071144k1d0bf30bv60656181edae8af7-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: uclinux-dist-devel-bounces-ZG0+EudsQA8dtHy/vicBwGD2FQJk+8+b@public.gmane.org Errors-To: uclinux-dist-devel-bounces-ZG0+EudsQA8dtHy/vicBwGD2FQJk+8+b@public.gmane.org List-Id: netdev.vger.kernel.org From: Mike Frysinger Date: Wed, 7 Oct 2009 14:44:45 -0400 > On Wed, Oct 7, 2009 at 14:47, Alexander Strakh wrote: >> =A0 =A0 =A0 =A0KERNEL_VERSION: 2.6.31 >> =A0 =A0 =A0 =A0DESCRIBE: >> Driver drivers/net/znet.c might sleep in atomic context, because it calls >> free_dma under claim_dma_lock: >> >> .drivers/net/znet.c: >> =A0168 static int znet_request_resources (struct net_device *dev) >> ... >> =A0189 =A0 =A0 =A0 =A0flags =3D claim_dma_lock(); >> =A0190 =A0 =A0 =A0 =A0free_dma (znet->tx_dma); >> =A0191 =A0 =A0 =A0 =A0release_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 Signed-off-by: David S. Miller --- 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 =3D 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 =3D claim_dma_lock(); free_dma (znet->tx_dma); - release_dma_lock (flags); free_rx_dma: - flags =3D 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 =3D netdev_priv(dev); - unsigned long flags; = release_region (znet->sia_base, znet->sia_size); release_region (dev->base_addr, znet->io_size); - flags =3D 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