From mboxrd@z Thu Jan 1 00:00:00 1970 From: akpm@linux-foundation.org Subject: [patch 11/13] PHYLIB: fix an interrupt loop potential when halting Date: Tue, 02 Oct 2007 14:11:43 -0700 Message-ID: <200710022111.l92LBhl5022507@imap1.linux-foundation.org> Cc: netdev@vger.kernel.org, akpm@linux-foundation.org, macro@linux-mips.org, afleming@freescale.com, jgarzik@pobox.com To: jeff@garzik.org Return-path: Received: from smtp2.linux-foundation.org ([207.189.120.14]:33089 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755424AbXJBVVu (ORCPT ); Tue, 2 Oct 2007 17:21:50 -0400 Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org From: "Maciej W. Rozycki" Ensure the PHY_HALTED state is not entered with the IRQ asserted as it could lead to an interrupt loop. There is a small window in phy_stop(), where the state of the PHY machine indicates it has been halted, but its interrupt output might still be unmasked. If an interrupt goes active right at this moment it will loop as the phy_interrupt() handler exits immediately with IRQ_NONE if the halted state is seen. It is unsafe to extend the phydev spinlock to cover phy_interrupt(). It is safe to swap the order of the actions though as all the competing places to unmask the interrupt output of the PHY, which are phy_change() and phy_timer() are already covered with the lock as is the sequence in question. Signed-off-by: Maciej W. Rozycki Cc: Andy Fleming Cc: Jeff Garzik Signed-off-by: Andrew Morton --- drivers/net/phy/phy.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff -puN drivers/net/phy/phy.c~phylib-fix-an-interrupt-loop-potential-when-halting drivers/net/phy/phy.c --- a/drivers/net/phy/phy.c~phylib-fix-an-interrupt-loop-potential-when-halting +++ a/drivers/net/phy/phy.c @@ -737,8 +737,6 @@ void phy_stop(struct phy_device *phydev) if (PHY_HALTED == phydev->state) goto out_unlock; - phydev->state = PHY_HALTED; - if (phydev->irq != PHY_POLL) { /* Disable PHY Interrupts */ phy_config_interrupt(phydev, PHY_INTERRUPT_DISABLED); @@ -747,6 +745,8 @@ void phy_stop(struct phy_device *phydev) phy_clear_interrupt(phydev); } + phydev->state = PHY_HALTED; + out_unlock: spin_unlock_bh(&phydev->lock); _