On Fri, Mar 01, 2013 at 03:01:56PM +0800, Li Zefan wrote: > rename() will change dentry->d_name. The result of this race can > be worse than seeing partially rewritten name, but we might access > a stale pointer because rename() will re-allocate memory to hold > a longer name. > > As accessing dentry->name must be protected by dentry->d_lock or > parent inode's i_mutex, while on the other hand cgroup-path() can > be called with some irq-safe spinlocks held, we can't generate > cgroup path using dentry->d_name. > > Alternatively we make a copy of dentry->d_name and save it in > cgrp->name when a cgroup is created, and update cgrp->name at > rename(). > > v5: use flexible array instead of zero-size array. > v4: - allocate root_cgroup_name and all root_cgroup->name points to it. > - add cgroup_name() wrapper. > v3: use kfree_rcu() instead of synchronize_rcu() in user-visible path. > v2: make cgrp->name RCU safe. > > Signed-off-by: Li Zefan <lizefan@xxxxxxxxxx> Applied 1-2 to cgroup/for-3.10. Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
