Half a year too late, but then it hadn't been posted on fsdevel. Which it really should have been, due to > + /* replace tcp socket to smc */ > + smcsock->file = tcp->file; > + smcsock->file->private_data = smcsock; > + smcsock->file->f_inode = SOCK_INODE(smcsock); /* replace inode when sock_close */ > + smcsock->file->f_path.dentry->d_inode = SOCK_INODE(smcsock); /* dput() in __fput */ > + tcp->file = NULL; this. It violates a bunch of rather fundamental assertions about the data structures you are playing with, and I'm not even going into the lifetime and refcounting issues. * ->d_inode of a busy positive dentry never changes while refcount of dentry remains positive. A lot of places in VFS rely upon that. * ->f_inode of a file never changes, period. * ->private_data of a struct file associated with a socket never changes; it can be accessed lockless, with no precautions beyond "make sure that refcount of struct file will remain positive". PS: more than one thread could be calling methods of that struct socket at the same time; what's to stop e.g. connect(2) on the same sucker (e.g. called on the same descriptor from a different thread that happens to share the same descriptor table) to be sitting there trying to lock the struct sock currently held locked by caller of tcp_set_ulp()?
