From 14cc571bb1d072d3f4be2875ea520ab03e093471 Mon Sep 17 00:00:00 2001 From: Arthur Jones Date: Fri, 25 Jul 2008 01:49:08 -0700 Subject: [PATCH] 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 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: Arthur Jones Signed-off-by: Doug Thompson Acked-by: Greg Kroah-Hartman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/edac/edac_pci_sysfs.c | 30 +++++++++++++++++++++--------- 1 file changed, 21 insertions(+), 9 deletions(-) diff --git a/drivers/edac/edac_pci_sysfs.c b/drivers/edac/edac_pci_sysfs.c index 2c1fa1bb6df2..5c153dccc95e 100644 --- a/drivers/edac/edac_pci_sysfs.c +++ b/drivers/edac/edac_pci_sysfs.c @@ -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); } } -- 2.20.1