"current" in kernel is a global macro, that always point to the "struct task_struct * " of the currently executing task (for details on task_struct, ref Robert Love, pg 24-27). Now I have a macro called push root which has the following purpose- "to push root user and group to current context so to set current uid and gid to 0." Now in kernel 3.8.3, I would do something like struct cred *new1; new1 =prepare_creds(); new1->uid = 0; new1->gid = 0; commit_creds(new1); So macro definition of push root, according to what I have proposed above, should be #define push_root \ new1 =prepare_creds(); \ new1->uid = 0; \ new1->gid = 0; \ commit_creds(new1) But I am getting errors like multiple declaration of new1 etc. Even if I declare prepare_creds outside macro definition like new1 =prepare_creds(); #define push_root \ new1->uid = 0; \ new1->gid = 0; \ commit_creds(new1) I think I am facing the issue that the macros are inlined during compilation, so when the compiler wants to replace them, it raises issues. I could think of two ways to solve this issue- 1. define a new macro like #define prep_root() which defines the var once for all, and that I have to put it at the begin of each function needing push_root. This is not a very good method. 2. I should still try to go with inlined functions but how ? Can someone suggest anything Regards, Saket Sinha