lkml.org 
[lkml]   [2012]   [Jun]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH] xen/mce: schedule a workqueue to avoid sleep in atomic context
    Date
    From aa2ce7440f16002266dc8464f749992d0c8ac0e5 Mon Sep 17 00:00:00 2001
    From: Liu, Jinsong <jinsong.liu@intel.com>
    Date: Tue, 12 Jun 2012 23:11:16 +0800
    Subject: [PATCH] xen/mce: schedule a workqueue to avoid sleep in atomic context

    copy_to_user might sleep and print a stack trace if it is executed
    in an atomic spinlock context.

    This patch schedule a workqueue for IRQ handler to poll the data,
    and use mutex instead of spinlock, so copy_to_user sleep in atomic
    context would not occur.

    Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
    Suggested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
    Signed-off-by: Liu, Jinsong <jinsong.liu@intel.com>
    ---
    drivers/xen/mcelog.c | 18 +++++++++++-------
    1 files changed, 11 insertions(+), 7 deletions(-)

    diff --git a/drivers/xen/mcelog.c b/drivers/xen/mcelog.c
    index 72e87d2..804aa3c 100644
    --- a/drivers/xen/mcelog.c
    +++ b/drivers/xen/mcelog.c
    @@ -55,7 +55,7 @@ static struct mc_info g_mi;
    static struct mcinfo_logical_cpu *g_physinfo;
    static uint32_t ncpus;

    -static DEFINE_SPINLOCK(mcelog_lock);
    +static DEFINE_MUTEX(mcelog_lock);

    static struct xen_mce_log xen_mcelog = {
    .signature = XEN_MCE_LOG_SIGNATURE,
    @@ -106,7 +106,7 @@ static ssize_t xen_mce_chrdev_read(struct file *filp, char __user *ubuf,
    unsigned num;
    int i, err;

    - spin_lock(&mcelog_lock);
    + mutex_lock(&mcelog_lock);

    num = xen_mcelog.next;

    @@ -130,7 +130,7 @@ static ssize_t xen_mce_chrdev_read(struct file *filp, char __user *ubuf,
    err = -EFAULT;

    out:
    - spin_unlock(&mcelog_lock);
    + mutex_unlock(&mcelog_lock);

    return err ? err : buf - ubuf;
    }
    @@ -310,12 +310,11 @@ static int mc_queue_handle(uint32_t flags)
    }

    /* virq handler for machine check error info*/
    -static irqreturn_t xen_mce_interrupt(int irq, void *dev_id)
    +static void xen_mce_work_fn(struct work_struct *work)
    {
    int err;
    - unsigned long tmp;

    - spin_lock_irqsave(&mcelog_lock, tmp);
    + mutex_lock(&mcelog_lock);

    /* urgent mc_info */
    err = mc_queue_handle(XEN_MC_URGENT);
    @@ -330,8 +329,13 @@ static irqreturn_t xen_mce_interrupt(int irq, void *dev_id)
    pr_err(XEN_MCELOG
    "Failed to handle nonurgent mc_info queue.\n");

    - spin_unlock_irqrestore(&mcelog_lock, tmp);
    + mutex_unlock(&mcelog_lock);
    +}
    +static DECLARE_WORK(xen_mce_work, xen_mce_work_fn);

    +static irqreturn_t xen_mce_interrupt(int irq, void *dev_id)
    +{
    + schedule_work(&xen_mce_work);
    return IRQ_HANDLED;
    }

    --
    1.7.1[unhandled content-type:application/octet-stream]
    \
     
     \ /
      Last update: 2012-06-12 10:21    [W:0.028 / U:0.212 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site