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authorAlexey Dobriyan <adobriyan@gmail.com>2009-03-25 22:48:06 +0300
committerAlexey Dobriyan <adobriyan@gmail.com>2009-03-31 01:14:44 +0400
commit99b76233803beab302123d243eea9e41149804f3 (patch)
tree398178210fe66845ccd6fa4258ba762a87e023ad /drivers/acpi/button.c
parent3dec7f59c370c7b58184d63293c3dc984d475840 (diff)
downloadop-kernel-dev-99b76233803beab302123d243eea9e41149804f3.zip
op-kernel-dev-99b76233803beab302123d243eea9e41149804f3.tar.gz
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 <adobriyan@gmail.com>
Diffstat (limited to 'drivers/acpi/button.c')
-rw-r--r--drivers/acpi/button.c3
1 files changed, 0 insertions, 3 deletions
diff --git a/drivers/acpi/button.c b/drivers/acpi/button.c
index 171fd91..c2f0606 100644
--- a/drivers/acpi/button.c
+++ b/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);
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