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| author | Alexey Dobriyan <adobriyan@gmail.com> | 2009-03-25 22:48:06 +0300 |
|---|---|---|
| committer | Alexey Dobriyan <adobriyan@gmail.com> | 2009-03-31 01:14:44 +0400 |
| commit | 99b76233803beab302123d243eea9e41149804f3 (patch) | |
| tree | 398178210fe66845ccd6fa4258ba762a87e023ad /Documentation | |
| parent | 3dec7f59c370c7b58184d63293c3dc984d475840 (diff) | |
| download | linux-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 'Documentation')
| -rw-r--r-- | Documentation/DocBook/procfs_example.c | 9 |
1 files changed, 0 insertions, 9 deletions
diff --git a/Documentation/DocBook/procfs_example.c b/Documentation/DocBook/procfs_example.c index 8c6396e4bf31..a5b11793b1e0 100644 --- a/Documentation/DocBook/procfs_example.c +++ b/Documentation/DocBook/procfs_example.c @@ -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, @@ -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 */ @@ -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) { @@ -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, @@ -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); |