[RFT PATCH] 8139cp: Fix possible dev_close / cp_interrupt race during MTU change
From: John Greene <hidden>
Date: 2012-12-14 12:16:36
Subsystem:
networking drivers, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
commit: cb64edb6b89491edfdbae52ba7db9a8b8391d339 upstream
Above commit may introduce a race between cp_interrupt and dev_close
/ change MTU / dev_open up state. Changes cp_interrupt to tolerate
this. Change spin_locking in cp_interrupt to avoid possible
but unobserved race.
Reported-by: "Francois Romieu" <romieu@fr.zoreil.com>
Tested on virtual hardware, Tx MTU size up to 4096, max tx payload
was ping -s 4068 for MTU of 4096. No real hardware, need test
assist.
Signed-off-by: "John Greene" <redacted>
CC: "David S. Miller" <davem@davemloft.net>
CC: "David Woodhouse" <redacted>
---
drivers/net/ethernet/realtek/8139cp.c | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)
diff --git a/drivers/net/ethernet/realtek/8139cp.c b/drivers/net/ethernet/realtek/8139cp.c
index 0da3f5e..585c35c 100644
--- a/drivers/net/ethernet/realtek/8139cp.c
+++ b/drivers/net/ethernet/realtek/8139cp.c@@ -577,28 +577,30 @@ static irqreturn_t cp_interrupt (int irq, void *dev_instance) { struct net_device *dev = dev_instance; struct cp_private *cp; + int handled = 0; u16 status; if (unlikely(dev == NULL)) return IRQ_NONE; cp = netdev_priv(dev); + spin_lock(&cp->lock); + status = cpr16(IntrStatus); if (!status || (status == 0xFFFF)) - return IRQ_NONE; + goto out_unlock; + + handled = 1; netif_dbg(cp, intr, dev, "intr, status %04x cmd %02x cpcmd %04x\n", status, cpr8(Cmd), cpr16(CpCmd)); cpw16(IntrStatus, status & ~cp_rx_intr_mask); - spin_lock(&cp->lock); - /* close possible race's with dev_close */ if (unlikely(!netif_running(dev))) { cpw16(IntrMask, 0); - spin_unlock(&cp->lock); - return IRQ_HANDLED; + goto out_unlock; } if (status & (RxOK | RxErr | RxEmpty | RxFIFOOvr))
@@ -612,7 +614,6 @@ static irqreturn_t cp_interrupt (int irq, void *dev_instance) if (status & LinkChg) mii_check_media(&cp->mii_if, netif_msg_link(cp), false); - spin_unlock(&cp->lock); if (status & PciErr) { u16 pci_status;
@@ -625,7 +626,10 @@ static irqreturn_t cp_interrupt (int irq, void *dev_instance) /* TODO: reset hardware */ } - return IRQ_HANDLED; +out_unlock: + spin_unlock(&cp->lock); + + return IRQ_RETVAL(handled); } #ifdef CONFIG_NET_POLL_CONTROLLER
--
1.7.11.7