Use change_pid() instead of detach_pid() + attach_pid() in sys_setpgid().
This way task_pgrp() is not NULL in between.
Signed-off-by: Oleg Nesterov <[email protected]>
--- 25/kernel/sys.c~3_SETPGRP 2008-02-18 19:15:40.000000000 +0300
+++ 25/kernel/sys.c 2008-03-20 18:21:17.000000000 +0300
@@ -972,8 +972,7 @@ asmlinkage long sys_setpgid(pid_t pid, p
goto out;
if (task_pgrp(p) != pgrp) {
- detach_pid(p, PIDTYPE_PGID);
- attach_pid(p, PIDTYPE_PGID, pgrp);
+ change_pid(p, PIDTYPE_PGID, pgrp);
set_task_pgrp(p, pid_nr(pgrp));
}