From patchwork Tue Feb 26 16:12:34 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [3.5.y.z, extended, stable] Patch "genirq: Avoid deadlock in spurious handling" has been added to staging queue Date: Tue, 26 Feb 2013 06:12:34 -0000 From: Luis Henriques X-Patchwork-Id: 223261 Message-Id: <1361895154-26414-1-git-send-email-luis.henriques@canonical.com> To: Thomas Gleixner Cc: kernel-team@lists.ubuntu.com, "Wang Song-Bo \(Stoney\)" This is a note to let you know that I have just added a patch titled genirq: Avoid deadlock in spurious handling to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.5.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ------ >From fd467039c01fd1404276dc9c1465898b6169d9c3 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 23 Nov 2012 10:08:44 +0100 Subject: [PATCH] genirq: Avoid deadlock in spurious handling commit e716efde75267eab919cdb2bef5b2cb77f305326 upstream. commit 52553ddf(genirq: fix regression in irqfixup, irqpoll) introduced a potential deadlock by calling the action handler with the irq descriptor lock held. Remove the call and let the handling code run even for an interrupt where only a single action is registered. That matches the goal of the above commit and avoids the deadlock. Document the confusing action = desc->action reload in the handling loop while at it. Reported-and-tested-by: "Wang, Warner" Tested-by: Edward Donovan Cc: "Wang, Song-Bo (Stoney)" Signed-off-by: Thomas Gleixner Signed-off-by: Luis Henriques --- kernel/irq/spurious.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) -- 1.8.1.2 diff --git a/kernel/irq/spurious.c b/kernel/irq/spurious.c index 611cd60..7b5f012 100644 --- a/kernel/irq/spurious.c +++ b/kernel/irq/spurious.c @@ -80,13 +80,11 @@ static int try_one_irq(int irq, struct irq_desc *desc, bool force) /* * All handlers must agree on IRQF_SHARED, so we test just the - * first. Check for action->next as well. + * first. */ action = desc->action; if (!action || !(action->flags & IRQF_SHARED) || - (action->flags & __IRQF_TIMER) || - (action->handler(irq, action->dev_id) == IRQ_HANDLED) || - !action->next) + (action->flags & __IRQF_TIMER)) goto out; /* Already running on another processor */ @@ -104,6 +102,7 @@ static int try_one_irq(int irq, struct irq_desc *desc, bool force) do { if (handle_irq_event(desc) == IRQ_HANDLED) ret = IRQ_HANDLED; + /* Make sure that there is still a valid action */ action = desc->action; } while ((desc->istate & IRQS_PENDING) && action); desc->istate &= ~IRQS_POLL_INPROGRESS;