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Message-ID: <20120116222835.GA4869@suse.de>
Date: Mon, 16 Jan 2012 14:28:35 -0800
From: Greg KH <gregkh@...e.de>
To: "Rafael J. Wysocki" <rjw@...k.pl>
Cc: Alan Stern <stern@...land.harvard.edu>,
"Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>,
Sergei Trofimovich <slyich@...il.com>,
linux-kernel@...r.kernel.org, Kay Sievers <kay.sievers@...y.org>,
Linux PM mailing list <linux-pm@...r.kernel.org>,
Tony Luck <tony.luck@...el.com>,
"mingo@...e.hu" <mingo@...e.hu>, Borislav Petkov <bp@...64.org>,
"tglx@...utronix.de" <tglx@...utronix.de>,
prasad@...ux.vnet.ibm.com
Subject: Re: 3.2.0-07927-gc49c41a: s2ram: Device 'machinecheck1' does not
have a release() function, it is broken and must be fixed
On Mon, Jan 16, 2012 at 11:08:49PM +0100, Rafael J. Wysocki wrote:
> On Monday, January 16, 2012, Alan Stern wrote:
> > On Mon, 16 Jan 2012, Rafael J. Wysocki wrote:
> >
> > > On Monday, January 16, 2012, Srivatsa S. Bhat wrote:
> >
> > > > Just to re-instate, an end-user need not really worry about this warning
> > > > too much since this was there before (at a different place, and hidden)
> > > > when things were working fine... Hence it would be worthwhile to fix
> > > > this warning "correctly" if possible, than just do a quick and dirty
> > > > "silence the warning" kind of workaround.
> > >
> > > Well, since there's nothing to release in there, I really see only two
> > > possible "fixes": either silence the warning the way you describe, or
> > > remove it from the core.
> >
> > No, the right fix is to release something. The device structures
> > should be allocated dynamically, not statically. Greg's suggestion of
> > using a set of per-cpu pointers to dynamically-allocated structures
> > sounds right.
>
> OK, so the source of the problem is that the device structure is statically
> allocated, right?
Yes, the patch below is what I am currently testing (my laptop is taking
a while to rebuild.) It shows the general idea here...
thanks,
greg k-h
diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h
index f35ce43..6aefb14 100644
--- a/arch/x86/include/asm/mce.h
+++ b/arch/x86/include/asm/mce.h
@@ -151,7 +151,7 @@ static inline void enable_p5_mce(void) {}
void mce_setup(struct mce *m);
void mce_log(struct mce *m);
-DECLARE_PER_CPU(struct device, mce_device);
+extern struct device *mce_device[CONFIG_NR_CPUS];
/*
* Maximum banks number.
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 29ba329..5a11ae2 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -1859,7 +1859,7 @@ static struct bus_type mce_subsys = {
.dev_name = "machinecheck",
};
-DEFINE_PER_CPU(struct device, mce_device);
+struct device *mce_device[CONFIG_NR_CPUS];
__cpuinitdata
void (*threshold_cpu_callback)(unsigned long action, unsigned int cpu);
@@ -2001,19 +2001,27 @@ static struct device_attribute *mce_device_attrs[] = {
static cpumask_var_t mce_device_initialized;
+static void mce_device_release(struct device *dev)
+{
+ kfree(dev);
+}
+
/* Per cpu device init. All of the cpus still share the same ctrl bank: */
static __cpuinit int mce_device_create(unsigned int cpu)
{
- struct device *dev = &per_cpu(mce_device, cpu);
+ struct device *dev;
int err;
int i, j;
if (!mce_available(&boot_cpu_data))
return -EIO;
- memset(dev, 0, sizeof(struct device));
+ dev = kzalloc(sizeof *dev, GFP_KERNEL);
+ if (!dev)
+ return -ENOMEM;
dev->id = cpu;
dev->bus = &mce_subsys;
+ dev->release = &mce_device_release;
err = device_register(dev);
if (err)
@@ -2030,6 +2038,7 @@ static __cpuinit int mce_device_create(unsigned int cpu)
goto error2;
}
cpumask_set_cpu(cpu, mce_device_initialized);
+ mce_device[cpu] = dev;
return 0;
error2:
@@ -2046,7 +2055,7 @@ error:
static __cpuinit void mce_device_remove(unsigned int cpu)
{
- struct device *dev = &per_cpu(mce_device, cpu);
+ struct device *dev = mce_device[cpu];
int i;
if (!cpumask_test_cpu(cpu, mce_device_initialized))
@@ -2060,6 +2069,7 @@ static __cpuinit void mce_device_remove(unsigned int cpu)
device_unregister(dev);
cpumask_clear_cpu(cpu, mce_device_initialized);
+ mce_device[cpu] = NULL;
}
/* Make sure there are no machine checks on offlined CPUs. */
diff --git a/arch/x86/kernel/cpu/mcheck/mce_amd.c b/arch/x86/kernel/cpu/mcheck/mce_amd.c
index ba0b94a..786e76a 100644
--- a/arch/x86/kernel/cpu/mcheck/mce_amd.c
+++ b/arch/x86/kernel/cpu/mcheck/mce_amd.c
@@ -523,6 +523,7 @@ static __cpuinit int threshold_create_bank(unsigned int cpu, unsigned int bank)
{
int i, err = 0;
struct threshold_bank *b = NULL;
+ struct device *dev = mce_device[cpu];
char name[32];
sprintf(name, "threshold_bank%i", bank);
@@ -543,8 +544,7 @@ static __cpuinit int threshold_create_bank(unsigned int cpu, unsigned int bank)
if (!b)
goto out;
- err = sysfs_create_link(&per_cpu(mce_device, cpu).kobj,
- b->kobj, name);
+ err = sysfs_create_link(&dev->kobj, b->kobj, name);
if (err)
goto out;
@@ -565,7 +565,7 @@ static __cpuinit int threshold_create_bank(unsigned int cpu, unsigned int bank)
goto out;
}
- b->kobj = kobject_create_and_add(name, &per_cpu(mce_device, cpu).kobj);
+ b->kobj = kobject_create_and_add(name, &dev->kobj);
if (!b->kobj)
goto out_free;
@@ -585,8 +585,9 @@ static __cpuinit int threshold_create_bank(unsigned int cpu, unsigned int bank)
if (i == cpu)
continue;
- err = sysfs_create_link(&per_cpu(mce_device, i).kobj,
- b->kobj, name);
+ dev = mce_device[i];
+ if (dev)
+ err = sysfs_create_link(&dev->kobj,b->kobj, name);
if (err)
goto out;
@@ -649,6 +650,7 @@ static void deallocate_threshold_block(unsigned int cpu,
static void threshold_remove_bank(unsigned int cpu, int bank)
{
struct threshold_bank *b;
+ struct device *dev;
char name[32];
int i = 0;
@@ -663,7 +665,7 @@ static void threshold_remove_bank(unsigned int cpu, int bank)
#ifdef CONFIG_SMP
/* sibling symlink */
if (shared_bank[bank] && b->blocks->cpu != cpu) {
- sysfs_remove_link(&per_cpu(mce_device, cpu).kobj, name);
+ sysfs_remove_link(&mce_device[cpu]->kobj, name);
per_cpu(threshold_banks, cpu)[bank] = NULL;
return;
@@ -675,7 +677,9 @@ static void threshold_remove_bank(unsigned int cpu, int bank)
if (i == cpu)
continue;
- sysfs_remove_link(&per_cpu(mce_device, i).kobj, name);
+ dev = mce_device[i];
+ if (dev)
+ sysfs_remove_link(&dev->kobj, name);
per_cpu(threshold_banks, i)[bank] = NULL;
}
--
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