• Alexey Dobriyan's avatar
    proc 2/2: remove struct proc_dir_entry::owner · 99b76233
    Alexey Dobriyan authored
    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=12454Signed-off-by: default avatarAlexey Dobriyan <adobriyan@gmail.com>
    99b76233
jfs_debug.c 2.76 KB