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author | 2009-03-25 22:48:06 +0300 | |
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committer | 2009-03-31 01:14:44 +0400 | |
commit | 99b76233803beab302123d243eea9e41149804f3 (patch) | |
tree | 398178210fe66845ccd6fa4258ba762a87e023ad /include/linux/proc_fs.h | |
parent | proc 1/2: do PDE usecounting even for ->read_proc, ->write_proc (diff) | |
download | linux-99b76233803beab302123d243eea9e41149804f3.tar.gz linux-99b76233803beab302123d243eea9e41149804f3.tar.bz2 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 'include/linux/proc_fs.h')
-rw-r--r-- | include/linux/proc_fs.h | 4 |
1 files changed, 0 insertions, 4 deletions
diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h index b8bdb96eff78..fbfa3d44d33d 100644 --- a/include/linux/proc_fs.h +++ b/include/linux/proc_fs.h @@ -41,9 +41,6 @@ enum { * while parent/subdir create the directory structure (every * /proc file has a parent, but "subdir" is NULL for all * non-directory entries). - * - * "owner" is used to protect module - * from unloading while proc_dir_entry is in use */ typedef int (read_proc_t)(char *page, char **start, off_t off, @@ -70,7 +67,6 @@ struct proc_dir_entry { * somewhere. */ const struct file_operations *proc_fops; - struct module *owner; struct proc_dir_entry *next, *parent, *subdir; void *data; read_proc_t *read_proc; |