proc 2/2: remove struct proc_dir_entry::owner

Setting ->owner as done currently (pde->owner = THIS_MODULE) is racy
as correctly noted at bug #12454. Someone can lookup entry with NULL
->owner, thus not pinning enything, and release it later resulting
in module refcount underflow.

We can keep ->owner and supply it at registration time like ->proc_fops
and ->data.

But this leaves ->owner as easy-manipulative field (just one C assignment)
and somebody will forget to unpin previous/pin current module when
switching ->owner. ->proc_fops is declared as "const" which should give
some thoughts.

->read_proc/->write_proc were just fixed to not require ->owner for
protection.

rmmod'ed directories will be empty and return "." and ".." -- no harm.
And directories with tricky enough readdir and lookup shouldn't be modular.
We definitely don't want such modular code.

Removing ->owner will also make PDE smaller.

So, let's nuke it.

Kudos to Jeff Layton for reminding about this, let's say, oversight.

http://bugzilla.kernel.org/show_bug.cgi?id=12454

Signed-off-by: Alexey Dobriyan <[email protected]>

drivers/acpi/ac.c

@@ -191,7 +191,6 @@ static int acpi_ac_add_fs(struct acpi_device *device)
 						     acpi_ac_dir);
 		if (!acpi_device_dir(device))
 			return -ENODEV;
-		acpi_device_dir(device)->owner = THIS_MODULE;
 	}
 
 	/* 'state' [R] */

drivers/acpi/battery.c

@@ -760,7 +760,6 @@ static int acpi_battery_add_fs(struct acpi_device *device)
 						     acpi_battery_dir);
 		if (!acpi_device_dir(device))
 			return -ENODEV;
-		acpi_device_dir(device)->owner = THIS_MODULE;
 	}
 
 	for (i = 0; i < ACPI_BATTERY_NUMFILES; ++i) {

drivers/acpi/button.c

@@ -200,12 +200,10 @@ static int acpi_button_add_fs(struct acpi_device *device)
 
 	if (!entry)
 		return -ENODEV;
-	entry->owner = THIS_MODULE;
 
 	acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device), entry);
 	if (!acpi_device_dir(device))
 		return -ENODEV;
-	acpi_device_dir(device)->owner = THIS_MODULE;
 
 	/* 'info' [R] */
 	entry = proc_create_data(ACPI_BUTTON_FILE_INFO,
@@ -522,7 +520,6 @@ static int __init acpi_button_init(void)
 	acpi_button_dir = proc_mkdir(ACPI_BUTTON_CLASS, acpi_root_dir);
 	if (!acpi_button_dir)
 		return -ENODEV;
-	acpi_button_dir->owner = THIS_MODULE;
 	result = acpi_bus_register_driver(&acpi_button_driver);
 	if (result < 0) {
 		remove_proc_entry(ACPI_BUTTON_CLASS, acpi_root_dir);

drivers/acpi/fan.c

@@ -193,7 +193,6 @@ static int acpi_fan_add_fs(struct acpi_device *device)
 						     acpi_fan_dir);
 		if (!acpi_device_dir(device))
 			return -ENODEV;
-		acpi_device_dir(device)->owner = THIS_MODULE;
 	}
 
 	/* 'status' [R/W] */
@@ -347,7 +346,6 @@ static int __init acpi_fan_init(void)
 	acpi_fan_dir = proc_mkdir(ACPI_FAN_CLASS, acpi_root_dir);
 	if (!acpi_fan_dir)
 		return -ENODEV;
-	acpi_fan_dir->owner = THIS_MODULE;
 #endif
 
 	result = acpi_bus_register_driver(&acpi_fan_driver);

drivers/acpi/processor_core.c

@@ -359,7 +359,6 @@ static int acpi_processor_add_fs(struct acpi_device *device)
 		if (!acpi_device_dir(device))
 			return -ENODEV;
 	}
-	acpi_device_dir(device)->owner = THIS_MODULE;
 
 	/* 'info' [R] */
 	entry = proc_create_data(ACPI_PROCESSOR_FILE_INFO,
@@ -1137,7 +1136,6 @@ static int __init acpi_processor_init(void)
 	acpi_processor_dir = proc_mkdir(ACPI_PROCESSOR_CLASS, acpi_root_dir);
 	if (!acpi_processor_dir)
 		return -ENOMEM;
-	acpi_processor_dir->owner = THIS_MODULE;
 
 	/*
 	 * Check whether the system is DMI table. If yes, OSPM

drivers/acpi/sbs.c

@@ -488,7 +488,6 @@ acpi_sbs_add_fs(struct proc_dir_entry **dir,
 		if (!*dir) {
 			return -ENODEV;
 		}
-		(*dir)->owner = THIS_MODULE;
 	}
 
 	/* 'info' [R] */

drivers/acpi/thermal.c

@@ -1506,7 +1506,6 @@ static int acpi_thermal_add_fs(struct acpi_device *device)
 						     acpi_thermal_dir);
 		if (!acpi_device_dir(device))
 			return -ENODEV;
-		acpi_device_dir(device)->owner = THIS_MODULE;
 	}
 
 	/* 'state' [R] */
@@ -1875,7 +1874,6 @@ static int __init acpi_thermal_init(void)
 	acpi_thermal_dir = proc_mkdir(ACPI_THERMAL_CLASS, acpi_root_dir);
 	if (!acpi_thermal_dir)
 		return -ENODEV;
-	acpi_thermal_dir->owner = THIS_MODULE;
 
 	result = acpi_bus_register_driver(&acpi_thermal_driver);
 	if (result < 0) {

drivers/acpi/video.c

@@ -1125,8 +1125,6 @@ static int acpi_video_device_add_fs(struct acpi_device *device)
 	if (!device_dir)
 		return -ENOMEM;
 
-	device_dir->owner = THIS_MODULE;
-
 	/* 'info' [R] */
 	entry = proc_create_data("info", S_IRUGO, device_dir,
 			&acpi_video_device_info_fops, acpi_driver_data(device));
@@ -1403,8 +1401,6 @@ static int acpi_video_bus_add_fs(struct acpi_device *device)
 	if (!device_dir)
 		return -ENOMEM;
 
-	device_dir->owner = THIS_MODULE;
-
 	/* 'info' [R] */
 	entry = proc_create_data("info", S_IRUGO, device_dir,
 				 &acpi_video_bus_info_fops,
@@ -2131,7 +2127,6 @@ static int __init acpi_video_init(void)
 	acpi_video_dir = proc_mkdir(ACPI_VIDEO_CLASS, acpi_root_dir);
 	if (!acpi_video_dir)
 		return -ENODEV;
-	acpi_video_dir->owner = THIS_MODULE;
 
 	result = acpi_bus_register_driver(&acpi_video_bus);
 	if (result < 0) {

drivers/block/ps3vram.c

@@ -551,8 +551,6 @@ static void __devinit ps3vram_proc_init(struct ps3_system_bus_device *dev)
 		dev_warn(&dev->core, "failed to create /proc entry\n");
 		return;
 	}
-
-	pde->owner = THIS_MODULE;
 	pde->data = priv;
 }
 

drivers/char/ipmi/ipmi_msghandler.c

@@ -1944,7 +1944,7 @@ static int stat_file_read_proc(char *page, char **start, off_t off,
 
 int ipmi_smi_add_proc_entry(ipmi_smi_t smi, char *name,
 			    read_proc_t *read_proc,
-			    void *data, struct module *owner)
+			    void *data)
 {
 	int                    rv = 0;
 #ifdef CONFIG_PROC_FS
@@ -1970,7 +1970,6 @@ int ipmi_smi_add_proc_entry(ipmi_smi_t smi, char *name,
 	} else {
 		file->data = data;
 		file->read_proc = read_proc;
-		file->owner = owner;
 
 		mutex_lock(&smi->proc_entry_lock);
 		/* Stick it on the list. */
@@ -1993,23 +1992,21 @@ static int add_proc_entries(ipmi_smi_t smi, int num)
 	smi->proc_dir = proc_mkdir(smi->proc_dir_name, proc_ipmi_root);
 	if (!smi->proc_dir)
 		rv = -ENOMEM;
-	else
-		smi->proc_dir->owner = THIS_MODULE;
 
 	if (rv == 0)
 		rv = ipmi_smi_add_proc_entry(smi, "stats",
 					     stat_file_read_proc,
-					     smi, THIS_MODULE);
+					     smi);
 
 	if (rv == 0)
 		rv = ipmi_smi_add_proc_entry(smi, "ipmb",
 					     ipmb_file_read_proc,
-					     smi, THIS_MODULE);
+					     smi);
 
 	if (rv == 0)
 		rv = ipmi_smi_add_proc_entry(smi, "version",
 					     version_file_read_proc,
-					     smi, THIS_MODULE);
+					     smi);
 #endif /* CONFIG_PROC_FS */
 
 	return rv;
@@ -4265,7 +4262,6 @@ static int ipmi_init_msghandler(void)
 	    return -ENOMEM;
 	}
 
-	proc_ipmi_root->owner = THIS_MODULE;
 #endif /* CONFIG_PROC_FS */
 
 	setup_timer(&ipmi_timer, ipmi_timeout, 0);

drivers/char/ipmi/ipmi_si_intf.c

@@ -2899,7 +2899,7 @@ static int try_smi_init(struct smi_info *new_smi)
 
 	rv = ipmi_smi_add_proc_entry(new_smi->intf, "type",
 				     type_file_read_proc,
-				     new_smi, THIS_MODULE);
+				     new_smi);
 	if (rv) {
 		printk(KERN_ERR
 		       "ipmi_si: Unable to create proc entry: %d\n",
@@ -2909,7 +2909,7 @@ static int try_smi_init(struct smi_info *new_smi)
 
 	rv = ipmi_smi_add_proc_entry(new_smi->intf, "si_stats",
 				     stat_file_read_proc,
-				     new_smi, THIS_MODULE);
+				     new_smi);
 	if (rv) {
 		printk(KERN_ERR
 		       "ipmi_si: Unable to create proc entry: %d\n",
@@ -2919,7 +2919,7 @@ static int try_smi_init(struct smi_info *new_smi)
 
 	rv = ipmi_smi_add_proc_entry(new_smi->intf, "params",
 				     param_read_proc,
-				     new_smi, THIS_MODULE);
+				     new_smi);
 	if (rv) {
 		printk(KERN_ERR
 		       "ipmi_si: Unable to create proc entry: %d\n",

drivers/input/input.c

@@ -903,8 +903,6 @@ static int __init input_proc_init(void)
 	if (!proc_bus_input_dir)
 		return -ENOMEM;
 
-	proc_bus_input_dir->owner = THIS_MODULE;
-
 	entry = proc_create("devices", 0, proc_bus_input_dir,
 			    &input_devices_fileops);
 	if (!entry)

drivers/isdn/hardware/eicon/divasi.c

@@ -118,7 +118,6 @@ static int DIVA_INIT_FUNCTION create_um_idi_proc(void)
 		return (0);
 
 	um_idi_proc_entry->read_proc = um_idi_proc_read;
-	um_idi_proc_entry->owner = THIS_MODULE;
 
 	return (1);
 }

drivers/media/video/cpia.c

@@ -1381,9 +1381,7 @@ static void proc_cpia_create(void)
 {
 	cpia_proc_root = proc_mkdir("cpia", NULL);
 
-	if (cpia_proc_root)
-		cpia_proc_root->owner = THIS_MODULE;
-	else
+	if (!cpia_proc_root)
 		LOG("Unable to initialise /proc/cpia\n");
 }
 

drivers/message/i2o/i2o_proc.c

@@ -2037,8 +2037,6 @@ static int __init i2o_proc_fs_create(void)
 	if (!i2o_proc_dir_root)
 		return -1;
 
-	i2o_proc_dir_root->owner = THIS_MODULE;
-
 	list_for_each_entry(c, &i2o_controllers, list)
 	    i2o_proc_iop_add(i2o_proc_dir_root, c);
 

drivers/net/bonding/bond_main.c

@@ -3444,25 +3444,12 @@ static void bond_remove_proc_entry(struct bonding *bond)
  */
 static void bond_create_proc_dir(void)
 {
-	int len = strlen(DRV_NAME);
-
-	for (bond_proc_dir = init_net.proc_net->subdir; bond_proc_dir;
-	     bond_proc_dir = bond_proc_dir->next) {
-		if ((bond_proc_dir->namelen == len) &&
-		    !memcmp(bond_proc_dir->name, DRV_NAME, len)) {
-			break;
-		}
-	}
-
 	if (!bond_proc_dir) {
 		bond_proc_dir = proc_mkdir(DRV_NAME, init_net.proc_net);
-		if (bond_proc_dir) {
-			bond_proc_dir->owner = THIS_MODULE;
-		} else {
+		if (!bond_proc_dir)
 			printk(KERN_WARNING DRV_NAME
 				": Warning: cannot create /proc/net/%s\n",
 				DRV_NAME);
-		}
 	}
 }
 
@@ -3471,25 +3458,7 @@ static void bond_create_proc_dir(void)
  */
 static void bond_destroy_proc_dir(void)
 {
-	struct proc_dir_entry *de;
-
-	if (!bond_proc_dir) {
-		return;
-	}
-
-	/* verify that the /proc dir is empty */
-	for (de = bond_proc_dir->subdir; de; de = de->next) {
-		/* ignore . and .. */
-		if (*(de->name) != '.') {
-			break;
-		}
-	}
-
-	if (de) {
-		if (bond_proc_dir->owner == THIS_MODULE) {
-			bond_proc_dir->owner = NULL;
-		}
-	} else {
+	if (bond_proc_dir) {
 		remove_proc_entry(DRV_NAME, init_net.proc_net);
 		bond_proc_dir = NULL;
 	}

drivers/net/irda/vlsi_ir.c

@@ -1871,13 +1871,6 @@ static int __init vlsi_mod_init(void)
 	 * without procfs - it's not required for the driver to work.
 	 */
 	vlsi_proc_root = proc_mkdir(PROC_DIR, NULL);
-	if (vlsi_proc_root) {
-		/* protect registered procdir against module removal.
-		 * Because we are in the module init path there's no race
-		 * window after create_proc_entry (and no barrier needed).
-		 */
-		vlsi_proc_root->owner = THIS_MODULE;
-	}
 
 	ret = pci_register_driver(&vlsi_irda_driver);
 

drivers/net/wireless/airo.c

@@ -4494,7 +4494,6 @@ static int setup_proc_entry( struct net_device *dev,
 		goto fail;
 	apriv->proc_entry->uid = proc_uid;
 	apriv->proc_entry->gid = proc_gid;
-	apriv->proc_entry->owner = THIS_MODULE;
 
 	/* Setup the StatsDelta */
 	entry = proc_create_data("StatsDelta",

drivers/platform/x86/asus_acpi.c

@@ -987,7 +987,6 @@ asus_proc_add(char *name, proc_writefunc *writefunc,
 	proc->write_proc = writefunc;
 	proc->read_proc = readfunc;
 	proc->data = acpi_driver_data(device);
-	proc->owner = THIS_MODULE;
 	proc->uid = asus_uid;
 	proc->gid = asus_gid;
 	return 0;
@@ -1020,7 +1019,6 @@ static int asus_hotk_add_fs(struct acpi_device *device)
 	if (proc) {
 		proc->read_proc = proc_read_info;
 		proc->data = acpi_driver_data(device);
-		proc->owner = THIS_MODULE;
 		proc->uid = asus_uid;
 		proc->gid = asus_gid;
 	} else {
@@ -1436,7 +1434,6 @@ static int __init asus_acpi_init(void)
 		printk(KERN_ERR "Asus ACPI: Unable to create /proc entry\n");
 		return -ENODEV;
 	}
-	asus_proc_dir->owner = THIS_MODULE;
 
 	result = acpi_bus_register_driver(&asus_hotk_driver);
 	if (result < 0) {

drivers/platform/x86/thinkpad_acpi.c

@@ -6992,7 +6992,6 @@ static int __init ibm_init(struct ibm_init_struct *iibm)
 			ret = -ENODEV;
 			goto err_out;
 		}
-		entry->owner = THIS_MODULE;
 		entry->data = ibm;
 		entry->read_proc = &dispatch_procfs_read;
 		if (ibm->write)
@@ -7405,7 +7404,6 @@ static int __init thinkpad_acpi_module_init(void)
 		thinkpad_acpi_module_exit();
 		return -ENODEV;
 	}
-	proc_dir->owner = THIS_MODULE;
 
 	ret = platform_driver_register(&tpacpi_pdriver);
 	if (ret) {

drivers/platform/x86/toshiba_acpi.c

@@ -679,8 +679,6 @@ static acpi_status __init add_device(void)
 					      toshiba_proc_dir,
 					      (read_proc_t *) dispatch_read,
 					      item);
-		if (proc)
-			proc->owner = THIS_MODULE;
 		if (proc && item->write_func)
 			proc->write_proc = (write_proc_t *) dispatch_write;
 	}
@@ -772,7 +770,6 @@ static int __init toshiba_acpi_init(void)
 		toshiba_acpi_exit();
 		return -ENODEV;
 	} else {
-		toshiba_proc_dir->owner = THIS_MODULE;
 		status = add_device();
 		if (ACPI_FAILURE(status)) {
 			toshiba_acpi_exit();

drivers/rtc/rtc-proc.c

@@ -105,14 +105,8 @@ static const struct file_operations rtc_proc_fops = {
 
 void rtc_proc_add_device(struct rtc_device *rtc)
 {
-	if (rtc->id == 0) {
-		struct proc_dir_entry *ent;
-
-		ent = proc_create_data("driver/rtc", 0, NULL,
-				       &rtc_proc_fops, rtc);
-		if (ent)
-			ent->owner = rtc->owner;
-	}
+	if (rtc->id == 0)
+		proc_create_data("driver/rtc", 0, NULL, &rtc_proc_fops, rtc);
 }
 
 void rtc_proc_del_device(struct rtc_device *rtc)

drivers/s390/block/dasd_proc.c

@@ -320,7 +320,6 @@ dasd_proc_init(void)
 	dasd_proc_root_entry = proc_mkdir("dasd", NULL);
 	if (!dasd_proc_root_entry)
 		goto out_nodasd;
-	dasd_proc_root_entry->owner = THIS_MODULE;
 	dasd_devices_entry = proc_create("devices",
 					 S_IFREG | S_IRUGO | S_IWUSR,
 					 dasd_proc_root_entry,
@@ -334,7 +333,6 @@ dasd_proc_init(void)
 		goto out_nostatistics;
 	dasd_statistics_entry->read_proc = dasd_statistics_read;
 	dasd_statistics_entry->write_proc = dasd_statistics_write;
-	dasd_statistics_entry->owner = THIS_MODULE;
 	return 0;
 
  out_nostatistics:

drivers/scsi/scsi_devinfo.c

@@ -596,8 +596,6 @@ int __init scsi_init_devinfo(void)
 		error = -ENOMEM;
 		goto out;
 	}
-
-	p->owner = THIS_MODULE;
 #endif /* CONFIG_SCSI_PROC_FS */
 
  out:

drivers/scsi/scsi_proc.c

@@ -115,8 +115,6 @@ void scsi_proc_hostdir_add(struct scsi_host_template *sht)
         	if (!sht->proc_dir)
 			printk(KERN_ERR "%s: proc_mkdir failed for %s\n",
 			       __func__, sht->proc_name);
-		else
-			sht->proc_dir->owner = sht->module;
 	}
 	mutex_unlock(&global_host_template_mutex);
 }
@@ -163,7 +161,6 @@ void scsi_proc_host_add(struct Scsi_Host *shost)
 	} 
 
 	p->write_proc = proc_scsi_write_proc;
-	p->owner = sht->module;
 }
 
 /**

drivers/video/via/viafbdev.c

@@ -2059,25 +2059,21 @@ static void viafb_init_proc(struct proc_dir_entry **viafb_entry)
 	if (viafb_entry) {
 		entry = create_proc_entry("dvp0", 0, *viafb_entry);
 		if (entry) {
-			entry->owner = THIS_MODULE;
 			entry->read_proc = viafb_dvp0_proc_read;
 			entry->write_proc = viafb_dvp0_proc_write;
 		}
 		entry = create_proc_entry("dvp1", 0, *viafb_entry);
 		if (entry) {
-			entry->owner = THIS_MODULE;
 			entry->read_proc = viafb_dvp1_proc_read;
 			entry->write_proc = viafb_dvp1_proc_write;
 		}
 		entry = create_proc_entry("dfph", 0, *viafb_entry);
 		if (entry) {
-			entry->owner = THIS_MODULE;
 			entry->read_proc = viafb_dfph_proc_read;
 			entry->write_proc = viafb_dfph_proc_write;
 		}
 		entry = create_proc_entry("dfpl", 0, *viafb_entry);
 		if (entry) {
-			entry->owner = THIS_MODULE;
 			entry->read_proc = viafb_dfpl_proc_read;
 			entry->write_proc = viafb_dfpl_proc_write;
 		}
@@ -2086,7 +2082,6 @@ static void viafb_init_proc(struct proc_dir_entry **viafb_entry)
 		    viaparinfo->chip_info->lvds_chip_info2.lvds_chip_name) {
 			entry = create_proc_entry("vt1636", 0, *viafb_entry);
 			if (entry) {
-				entry->owner = THIS_MODULE;
 				entry->read_proc = viafb_vt1636_proc_read;
 				entry->write_proc = viafb_vt1636_proc_write;
 			}