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author | Alexey Dobriyan <adobriyan@gmail.com> | 2009-03-25 20:48:06 +0100 |
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committer | Alexey Dobriyan <adobriyan@gmail.com> | 2009-03-30 23:14:44 +0200 |
commit | 99b76233803beab302123d243eea9e41149804f3 (patch) | |
tree | 398178210fe66845ccd6fa4258ba762a87e023ad /drivers/acpi/button.c | |
parent | proc 1/2: do PDE usecounting even for ->read_proc, ->write_proc (diff) | |
download | linux-99b76233803beab302123d243eea9e41149804f3.tar.xz linux-99b76233803beab302123d243eea9e41149804f3.zip |
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.c | 3 |
1 files changed, 0 insertions, 3 deletions
diff --git a/drivers/acpi/button.c b/drivers/acpi/button.c index 171fd914f435..c2f06069dcd4 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); |