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proc 2/2: remove struct proc_dir_entry::owner
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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]>
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Alexey Dobriyan committed Mar 30, 2009
1 parent 3dec7f5 commit 99b7623
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Showing 55 changed files with 26 additions and 232 deletions.
9 changes: 0 additions & 9 deletions Documentation/DocBook/procfs_example.c
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Original file line number Diff line number Diff line change
Expand Up @@ -117,9 +117,6 @@ static int __init init_procfs_example(void)
rv = -ENOMEM;
goto out;
}

example_dir->owner = THIS_MODULE;

/* create jiffies using convenience function */
jiffies_file = create_proc_read_entry("jiffies",
0444, example_dir,
Expand All @@ -130,8 +127,6 @@ static int __init init_procfs_example(void)
goto no_jiffies;
}

jiffies_file->owner = THIS_MODULE;

/* create foo and bar files using same callback
* functions
*/
Expand All @@ -146,7 +141,6 @@ static int __init init_procfs_example(void)
foo_file->data = &foo_data;
foo_file->read_proc = proc_read_foobar;
foo_file->write_proc = proc_write_foobar;
foo_file->owner = THIS_MODULE;

bar_file = create_proc_entry("bar", 0644, example_dir);
if(bar_file == NULL) {
Expand All @@ -159,7 +153,6 @@ static int __init init_procfs_example(void)
bar_file->data = &bar_data;
bar_file->read_proc = proc_read_foobar;
bar_file->write_proc = proc_write_foobar;
bar_file->owner = THIS_MODULE;

/* create symlink */
symlink = proc_symlink("jiffies_too", example_dir,
Expand All @@ -169,8 +162,6 @@ static int __init init_procfs_example(void)
goto no_symlink;
}

symlink->owner = THIS_MODULE;

/* everything OK */
printk(KERN_INFO "%s %s initialised\n",
MODULE_NAME, MODULE_VERS);
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5 changes: 0 additions & 5 deletions arch/alpha/kernel/srm_env.c
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Original file line number Diff line number Diff line change
Expand Up @@ -218,7 +218,6 @@ srm_env_init(void)
BASE_DIR);
goto cleanup;
}
base_dir->owner = THIS_MODULE;

/*
* Create per-name subdirectory
Expand All @@ -229,7 +228,6 @@ srm_env_init(void)
BASE_DIR, NAMED_DIR);
goto cleanup;
}
named_dir->owner = THIS_MODULE;

/*
* Create per-number subdirectory
Expand All @@ -241,7 +239,6 @@ srm_env_init(void)
goto cleanup;

}
numbered_dir->owner = THIS_MODULE;

/*
* Create all named nodes
Expand All @@ -254,7 +251,6 @@ srm_env_init(void)
goto cleanup;

entry->proc_entry->data = (void *) entry;
entry->proc_entry->owner = THIS_MODULE;
entry->proc_entry->read_proc = srm_env_read;
entry->proc_entry->write_proc = srm_env_write;

Expand All @@ -275,7 +271,6 @@ srm_env_init(void)

entry->id = var_num;
entry->proc_entry->data = (void *) entry;
entry->proc_entry->owner = THIS_MODULE;
entry->proc_entry->read_proc = srm_env_read;
entry->proc_entry->write_proc = srm_env_write;
}
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1 change: 0 additions & 1 deletion arch/blackfin/mm/sram-alloc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -854,7 +854,6 @@ static int __init sram_proc_init(void)
printk(KERN_WARNING "unable to create /proc/sram\n");
return -1;
}
ptr->owner = THIS_MODULE;
ptr->read_proc = sram_proc_read;
return 0;
}
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2 changes: 0 additions & 2 deletions arch/ia64/kernel/palinfo.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1002,8 +1002,6 @@ create_palinfo_proc_entries(unsigned int cpu)
*pdir = create_proc_read_entry(
palinfo_entries[j].name, 0, cpu_dir,
palinfo_read_entry, (void *)f.value);
if (*pdir)
(*pdir)->owner = THIS_MODULE;
pdir++;
}
}
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9 changes: 2 additions & 7 deletions arch/ia64/sn/kernel/sn2/prominfo_proc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -225,7 +225,6 @@ static struct proc_dir_entry *sgi_prominfo_entry;
int __init prominfo_init(void)
{
struct proc_dir_entry **entp;
struct proc_dir_entry *p;
cnodeid_t cnodeid;
unsigned long nasid;
int size;
Expand All @@ -246,14 +245,10 @@ int __init prominfo_init(void)
sprintf(name, "node%d", cnodeid);
*entp = proc_mkdir(name, sgi_prominfo_entry);
nasid = cnodeid_to_nasid(cnodeid);
p = create_proc_read_entry("fit", 0, *entp, read_fit_entry,
create_proc_read_entry("fit", 0, *entp, read_fit_entry,
(void *)nasid);
if (p)
p->owner = THIS_MODULE;
p = create_proc_read_entry("version", 0, *entp,
create_proc_read_entry("version", 0, *entp,
read_version_entry, (void *)nasid);
if (p)
p->owner = THIS_MODULE;
entp++;
}

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1 change: 0 additions & 1 deletion arch/powerpc/kernel/rtas_flash.c
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Original file line number Diff line number Diff line change
Expand Up @@ -669,7 +669,6 @@ static void remove_flash_pde(struct proc_dir_entry *dp)
{
if (dp) {
kfree(dp->data);
dp->owner = NULL;
remove_proc_entry(dp->name, dp->parent);
}
}
Expand Down
1 change: 0 additions & 1 deletion arch/sparc/kernel/led.c
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Original file line number Diff line number Diff line change
Expand Up @@ -126,7 +126,6 @@ static int __init led_init(void)
led = proc_create("led", 0, NULL, &led_proc_fops);
if (!led)
return -ENOMEM;
led->owner = THIS_MODULE;

printk(KERN_INFO
"led: version %s, Lars Kotthoff <[email protected]>\n",
Expand Down
10 changes: 1 addition & 9 deletions arch/x86/kernel/cpu/mtrr/if.c
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Original file line number Diff line number Diff line change
Expand Up @@ -377,10 +377,6 @@ static const struct file_operations mtrr_fops = {
.release = mtrr_close,
};


static struct proc_dir_entry *proc_root_mtrr;


static int mtrr_seq_show(struct seq_file *seq, void *offset)
{
char factor;
Expand Down Expand Up @@ -423,11 +419,7 @@ static int __init mtrr_if_init(void)
(!cpu_has(c, X86_FEATURE_CENTAUR_MCR)))
return -ENODEV;

proc_root_mtrr =
proc_create("mtrr", S_IWUSR | S_IRUGO, NULL, &mtrr_fops);

if (proc_root_mtrr)
proc_root_mtrr->owner = THIS_MODULE;
proc_create("mtrr", S_IWUSR | S_IRUGO, NULL, &mtrr_fops);
return 0;
}

Expand Down
1 change: 0 additions & 1 deletion drivers/acpi/ac.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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] */
Expand Down
1 change: 0 additions & 1 deletion drivers/acpi/battery.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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) {
Expand Down
3 changes: 0 additions & 3 deletions drivers/acpi/button.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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,
Expand Down Expand Up @@ -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);
Expand Down
2 changes: 0 additions & 2 deletions drivers/acpi/fan.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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] */
Expand Down Expand Up @@ -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);
Expand Down
2 changes: 0 additions & 2 deletions drivers/acpi/processor_core.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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,
Expand Down Expand Up @@ -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
Expand Down
1 change: 0 additions & 1 deletion drivers/acpi/sbs.c
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Original file line number Diff line number Diff line change
Expand Up @@ -488,7 +488,6 @@ acpi_sbs_add_fs(struct proc_dir_entry **dir,
if (!*dir) {
return -ENODEV;
}
(*dir)->owner = THIS_MODULE;
}

/* 'info' [R] */
Expand Down
2 changes: 0 additions & 2 deletions drivers/acpi/thermal.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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] */
Expand Down Expand Up @@ -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) {
Expand Down
5 changes: 0 additions & 5 deletions drivers/acpi/video.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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));
Expand Down Expand Up @@ -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,
Expand Down Expand Up @@ -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) {
Expand Down
2 changes: 0 additions & 2 deletions drivers/block/ps3vram.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
}

Expand Down
12 changes: 4 additions & 8 deletions drivers/char/ipmi/ipmi_msghandler.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand All @@ -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. */
Expand All @@ -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;
Expand Down Expand Up @@ -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);
Expand Down
6 changes: 3 additions & 3 deletions drivers/char/ipmi/ipmi_si_intf.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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",
Expand All @@ -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",
Expand All @@ -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",
Expand Down
2 changes: 0 additions & 2 deletions drivers/input/input.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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)
Expand Down
1 change: 0 additions & 1 deletion drivers/isdn/hardware/eicon/divasi.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);
}
Expand Down
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