From aa25ab7d943a5e1e6bcc2a65ff6669144f5b5d60 Mon Sep 17 00:00:00 2001 From: Neil Horman Date: Wed, 11 Aug 2010 05:12:57 +0000 Subject: 3c59x: Fix deadlock between boomerang_interrupt and boomerang_start_tx If netconsole is in use, there is a possibility for deadlock in 3c59x between boomerang_interrupt and boomerang_start_xmit. Both routines take the vp->lock, and if netconsole is in use, a pr_* call from the boomerang_interrupt routine will result in the netconsole code attempting to trnasmit an skb, which can try to take the same spin lock, resulting in deadlock. The fix is pretty straightforward. This patch allocats a bit in the 3c59x private structure to indicate that its handling an interrupt. If we get into the transmit routine and that bit is set, we can be sure that we have recursed and will deadlock if we continue, so instead we just return NETDEV_TX_BUSY, so the stack requeues the skb to try again later. Signed-off-by: Neil Horman Signed-off-by: David S. Miller --- drivers/net/3c59x.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) (limited to 'drivers/net/3c59x.c') diff --git a/drivers/net/3c59x.c b/drivers/net/3c59x.c index c754d88e5ec9..c685a55fc2f4 100644 --- a/drivers/net/3c59x.c +++ b/drivers/net/3c59x.c @@ -633,7 +633,8 @@ struct vortex_private { open:1, medialock:1, must_free_region:1, /* Flag: if zero, Cardbus owns the I/O region */ - large_frames:1; /* accept large frames */ + large_frames:1, /* accept large frames */ + handling_irq:1; /* private in_irq indicator */ int drv_flags; u16 status_enable; u16 intr_enable; @@ -2133,6 +2134,15 @@ boomerang_start_xmit(struct sk_buff *skb, struct net_device *dev) dev->name, vp->cur_tx); } + /* + * We can't allow a recursion from our interrupt handler back into the + * tx routine, as they take the same spin lock, and that causes + * deadlock. Just return NETDEV_TX_BUSY and let the stack try again in + * a bit + */ + if (vp->handling_irq) + return NETDEV_TX_BUSY; + if (vp->cur_tx - vp->dirty_tx >= TX_RING_SIZE) { if (vortex_debug > 0) pr_warning("%s: BUG! Tx Ring full, refusing to send buffer.\n", @@ -2335,11 +2345,13 @@ boomerang_interrupt(int irq, void *dev_id) ioaddr = vp->ioaddr; + /* * It seems dopey to put the spinlock this early, but we could race against vortex_tx_timeout * and boomerang_start_xmit */ spin_lock(&vp->lock); + vp->handling_irq = 1; status = ioread16(ioaddr + EL3_STATUS); @@ -2447,6 +2459,7 @@ boomerang_interrupt(int irq, void *dev_id) pr_debug("%s: exiting interrupt, status %4.4x.\n", dev->name, status); handler_exit: + vp->handling_irq = 0; spin_unlock(&vp->lock); return IRQ_HANDLED; } -- cgit v1.2.3 From 24cd804d1dc60a74c53da983094df3516500c276 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Mon, 30 Aug 2010 14:15:33 +0000 Subject: 3c59x: Remove incorrect locking; correct documented lock hierarchy vortex_ioctl() was grabbing vortex_private::lock around its call to generic_mii_ioctl(). This is no longer necessary since there are more specific locks which the mdio_{read,write}() functions will obtain. Worse, those functions do not save and restore IRQ flags when locking the MII state, so interrupts will be enabled when generic_mii_ioctl() returns. Since there is currently no need for any function to call mdio_{read,write}() while holding another spinlock, do not change them to save and restore IRQ flags but remove the specification of ordering between vortex_private::lock and vortex_private::mii_lock. Signed-off-by: Ben Hutchings Signed-off-by: David S. Miller --- drivers/net/3c59x.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) (limited to 'drivers/net/3c59x.c') diff --git a/drivers/net/3c59x.c b/drivers/net/3c59x.c index c685a55fc2f4..a045559c81cf 100644 --- a/drivers/net/3c59x.c +++ b/drivers/net/3c59x.c @@ -647,7 +647,7 @@ struct vortex_private { u16 io_size; /* Size of PCI region (for release_region) */ /* Serialises access to hardware other than MII and variables below. - * The lock hierarchy is rtnl_lock > lock > mii_lock > window_lock. */ + * The lock hierarchy is rtnl_lock > {lock, mii_lock} > window_lock. */ spinlock_t lock; spinlock_t mii_lock; /* Serialises access to MII */ @@ -2984,7 +2984,6 @@ static int vortex_ioctl(struct net_device *dev, struct ifreq *rq, int cmd) { int err; struct vortex_private *vp = netdev_priv(dev); - unsigned long flags; pci_power_t state = 0; if(VORTEX_PCI(vp)) @@ -2994,9 +2993,7 @@ static int vortex_ioctl(struct net_device *dev, struct ifreq *rq, int cmd) if(state != 0) pci_set_power_state(VORTEX_PCI(vp), PCI_D0); - spin_lock_irqsave(&vp->lock, flags); err = generic_mii_ioctl(&vp->mii, if_mii(rq), cmd, NULL); - spin_unlock_irqrestore(&vp->lock, flags); if(state != 0) pci_set_power_state(VORTEX_PCI(vp), state); -- cgit v1.2.3 From 89b12faba4f3441c9457c5278851e8a93ffd008d Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Mon, 6 Sep 2010 18:28:56 -0700 Subject: 3c59x: Fix deadlock in vortex_error() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This fixes a bug introduced in commit de847272149365363a6043a963a6f42fb91566e2 "3c59x: Use fine-grained locks for MII and windowed register access". vortex_interrupt() holds vp->window_lock over multiple register accesses to reduce locking overhead. However it also needs to call vortex_error() sometimes, and that uses the regular functions for access to windowed registers, which will try to acquire window_lock again. Therefore, drop window_lock around the call to vortex_error() and set the window afterward reacquiring the lock. Since vortex_error() may call vortex_rx(), which *does* require its caller to hold window_lock, lift that call up into vortex_interrupt(). This also removes the potential for calling vortex_rx() on a later-generation NIC. Reported-and-tested-by: Jens Schüßler [in Debian's 2.6.32] Signed-off-by: Ben Hutchings Signed-off-by: David S. Miller --- drivers/net/3c59x.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'drivers/net/3c59x.c') diff --git a/drivers/net/3c59x.c b/drivers/net/3c59x.c index a045559c81cf..85671adae455 100644 --- a/drivers/net/3c59x.c +++ b/drivers/net/3c59x.c @@ -1994,10 +1994,9 @@ vortex_error(struct net_device *dev, int status) } } - if (status & RxEarly) { /* Rx early is unused. */ - vortex_rx(dev); + if (status & RxEarly) /* Rx early is unused. */ iowrite16(AckIntr | RxEarly, ioaddr + EL3_CMD); - } + if (status & StatsFull) { /* Empty statistics. */ static int DoneDidThat; if (vortex_debug > 4) @@ -2298,7 +2297,12 @@ vortex_interrupt(int irq, void *dev_id) if (status & (HostError | RxEarly | StatsFull | TxComplete | IntReq)) { if (status == 0xffff) break; + if (status & RxEarly) + vortex_rx(dev); + spin_unlock(&vp->window_lock); vortex_error(dev, status); + spin_lock(&vp->window_lock); + window_set(vp, 7); } if (--work_done < 0) { -- cgit v1.2.3