On Fri, Oct 07, 2016 at 01:35:52PM -0700, Calvin Owens wrote: > Omitting the owner field in file_operations declared in modules is an > easy mistake to make, and can result in crashes when the module is > unloaded while userspace is poking the file. > > This patch modifies fops_get() to WARN when it encounters a NULL owner, > since in this case it cannot take a reference on the containing module. NAK. This is complete crap - we do *NOT* need ->owner on a lot of file_operations. * we do not need that on file_operations of a regular file or directory on a normal filesystem, since that filesystem is not going away until the file has been closed - ->f_path.mnt is holding a reference to vfsmount, which is holding a reference to superblock, which is holding a reference to file_system_type, which is holding a reference to _its_ ->owner. * we do not need that on anything on procfs - module removal is legal while a procfs file is opened; its cleanup will be blocked for the duration of ->read(), ->write(), etc. calls. If anything, we would be better off with modifications that would get rid of ->owner on file_operations. It's not trivial to do, but it might be not impossible. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
