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Commit 14cc571b authored by Arthur Jones's avatar Arthur Jones Committed by Linus Torvalds
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edac: core fix to use dynamic kobject 



Static kobjects are not supported in linux kernel.  Convert the
edac_pci_top_main_kobj from static to dynamic.  This avoids the double
free of the edac_pci_top_main_kobj.name that we see on module reload of
the e752x edac driver (and probably others as well).

In addition Greg KH <greg@kroah.com> has pointed out that this code may be
cleaned up significantly.  I will look at that as a follow-on patch, for
now, I just want the minimum fix to get this double-free oops bug
squashed...

Many thanks to Greg KH for his patience in showing me what the
Documentation/kobject.txt already said (oops)...

Signed-off-by: default avatarArthur Jones <ajones@riverbed.com>
Signed-off-by: default avatarDoug Thompson <dougthompson@xmission.com>
Acked-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b238e577

drivers/edac/edac_pci_sysfs.c

+21 −9
Original line number Diff line number Diff line
@@ -28,7 +28,7 @@ static int edac_pci_poll_msec = 1000; /* one second workq period */ 
static atomic_t pci_parity_count = ATOMIC_INIT(0);

static atomic_t pci_nonparity_count = ATOMIC_INIT(0);



static struct kobject edac_pci_top_main_kobj;

static struct kobject *edac_pci_top_main_kobj;

static atomic_t edac_pci_sysfs_refcount = ATOMIC_INIT(0);



/* getter functions for the data variables */
@@ -83,7 +83,7 @@ static void edac_pci_instance_release(struct kobject *kobj) 
	pci = to_instance(kobj);



	/* decrement reference count on top main kobj */

	kobject_put(&edac_pci_top_main_kobj);

	kobject_put(edac_pci_top_main_kobj);



	kfree(pci);	/* Free the control struct */

}
@@ -166,7 +166,7 @@ static int edac_pci_create_instance_kobj(struct edac_pci_ctl_info *pci, int idx) 
	 * track the number of PCI instances we have, and thus nest

	 * properly on keeping the module loaded

	 */

	main_kobj = kobject_get(&edac_pci_top_main_kobj);

	main_kobj = kobject_get(edac_pci_top_main_kobj);

	if (!main_kobj) {

		err = -ENODEV;

		goto error_out;
@@ -174,11 +174,11 @@ static int edac_pci_create_instance_kobj(struct edac_pci_ctl_info *pci, int idx) 


	/* And now register this new kobject under the main kobj */

	err = kobject_init_and_add(&pci->kobj, &ktype_pci_instance,

				   &edac_pci_top_main_kobj, "pci%d", idx);

				   edac_pci_top_main_kobj, "pci%d", idx);

	if (err != 0) {

		debugf2("%s() failed to register instance pci%d\n",

			__func__, idx);

		kobject_put(&edac_pci_top_main_kobj);

		kobject_put(edac_pci_top_main_kobj);

		goto error_out;

	}
@@ -316,9 +316,10 @@ static struct edac_pci_dev_attribute *edac_pci_attr[] = { 
 */

static void edac_pci_release_main_kobj(struct kobject *kobj)

{



	debugf0("%s() here to module_put(THIS_MODULE)\n", __func__);



	kfree(kobj);



	/* last reference to top EDAC PCI kobject has been removed,

	 * NOW release our ref count on the core module

	 */
@@ -369,8 +370,16 @@ static int edac_pci_main_kobj_setup(void) 
		goto decrement_count_fail;

	}



	edac_pci_top_main_kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL);

	if (!edac_pci_top_main_kobj) {

		debugf1("Failed to allocate\n");

		err = -ENOMEM;

		goto kzalloc_fail;

	}



	/* Instanstiate the pci object */

	err = kobject_init_and_add(&edac_pci_top_main_kobj, &ktype_edac_pci_main_kobj,

	err = kobject_init_and_add(edac_pci_top_main_kobj,

				   &ktype_edac_pci_main_kobj,

				   &edac_class->kset.kobj, "pci");

	if (err) {

		debugf1("Failed to register '.../edac/pci'\n");
@@ -381,13 +390,16 @@ static int edac_pci_main_kobj_setup(void) 
	 * for EDAC PCI, then edac_pci_main_kobj_teardown()

	 * must be used, for resources to be cleaned up properly

	 */

	kobject_uevent(&edac_pci_top_main_kobj, KOBJ_ADD);

	kobject_uevent(edac_pci_top_main_kobj, KOBJ_ADD);

	debugf1("Registered '.../edac/pci' kobject\n");



	return 0;



	/* Error unwind statck */

kobject_init_and_add_fail:

	kfree(edac_pci_top_main_kobj);



kzalloc_fail:

	module_put(THIS_MODULE);



decrement_count_fail:
@@ -414,7 +426,7 @@ static void edac_pci_main_kobj_teardown(void) 
	if (atomic_dec_return(&edac_pci_sysfs_refcount) == 0) {

		debugf0("%s() called kobject_put on main kobj\n",

			__func__);

		kobject_put(&edac_pci_top_main_kobj);

		kobject_put(edac_pci_top_main_kobj);

	}

}