signal: Use PIDTYPE_TGID to clearly store where file signals will be sent
When f_setown is called a pid and a pid type are stored. Replace the use
of PIDTYPE_PID with PIDTYPE_TGID as PIDTYPE_TGID goes to the entire thread
group. Replace the use of PIDTYPE_MAX with PIDTYPE_PID as PIDTYPE_PID now
is only for a thread.
Update the users of __f_setown to use PIDTYPE_TGID instead of
PIDTYPE_PID.
For now the code continues to capture task_pid (when task_tgid would
really be appropriate), and iterate on PIDTYPE_PID (even when type ==
PIDTYPE_TGID) out of an abundance of caution to preserve existing
behavior.
Oleg Nesterov suggested using the test to ensure we use PIDTYPE_PID
for tgid lookup also be used to avoid taking the tasklist lock.
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
diff --git a/fs/locks.c b/fs/locks.c
index db7b691..cfc059b 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -546,7 +546,7 @@ lease_setup(struct file_lock *fl, void **priv)
if (!fasync_insert_entry(fa->fa_fd, filp, &fl->fl_fasync, fa))
*priv = NULL;
- __f_setown(filp, task_pid(current), PIDTYPE_PID, 0);
+ __f_setown(filp, task_pid(current), PIDTYPE_TGID, 0);
}
static const struct lock_manager_operations lease_manager_ops = {