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| author | Liu, Jinsong <jinsong.liu@intel.com> | 2012-06-12 17:11:16 +0200 |
|---|---|---|
| committer | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2012-07-19 21:51:40 +0200 |
| commit | 1b2a05516e42149a5e9f0f5aeba2c7fa9574b3f4 (patch) | |
| tree | b3ebd18e79b2ef3db67dc9d457898c1d791d0fca /drivers/xen | |
| parent | xen/pcpu: Xen physical cpus online/offline sys interface (diff) | |
| download | linux-1b2a05516e42149a5e9f0f5aeba2c7fa9574b3f4.tar.xz linux-1b2a05516e42149a5e9f0f5aeba2c7fa9574b3f4.zip | |
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. Like this:
(XEN) CMCI: send CMCI to DOM0 through virq
BUG: sleeping function called from invalid context at /home/konradinux/kernel.h:199
in_atomic(): 1, irqs_disabled(): 0, pid: 4581, name: mcelog
Pid: 4581, comm: mcelog Tainted: G O 3.5.0-rc1upstream-00003-g149000b-dirty #1
[<ffffffff8109ad9a>] __might_sleep+0xda/0x100
[<ffffffff81329b0b>] xen_mce_chrdev_read+0xab/0x140
[<ffffffff81148945>] vfs_read+0xc5/0x190
[<ffffffff81148b0c>] sys_read+0x4c/0x90
[<ffffffff815bd039>] system_call_fastpath+0x16
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>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'drivers/xen')
| -rw-r--r-- | 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 72e87d2f1929..804aa3c181c2 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; } |