proc: don't (ab)use ->group_leader in proc_task_readdir() paths

proc_task_readdir() does not really need "leader", first_tid() has to
revalidate it anyway.  Just pass proc_pid(inode) to first_tid() instead,
it can do pid_task(PIDTYPE_PID) itself and read ->group_leader only if

The patch also extracts the "inode is dead" code from
pid_delete_dentry(dentry) into the new trivial helper,
proc_inode_is_dead(inode), proc_task_readdir() uses it to return -ENOENT
if this dir was removed.

This is a bit racy, but the race is very inlikely and the getdents() after
openndir() can see the empty "." + ".." dir only once.

Signed-off-by: Oleg Nesterov <>
Cc: "Eric W. Biederman" <>
Cc: Michal Hocko <>
Cc: Sameer Nanda <>
Cc: Sergey Dyasly <>
Signed-off-by: Andrew Morton <>
Signed-off-by: Linus Torvalds <>
1 file changed