tree cc649fd249aef0c4d227406b17a1a75c9d327e50
parent 3547ff3aefbe092ca35506c60c02e2d17a4f2199
author Oleg Nesterov <oleg@tv-sign.ru> 1209541971 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> 1209569375 -0700

signals: send_sig_info: don't take tasklist_lock

The comment in send_sig_info() is wrong, tasklist_lock can't help.

The caller must ensure the task can't go away, otherwise ->sighand can be NULL
even before we take the lock.

p->sighand could be changed by exec(), but I can't imagine how it is possible
to prevent exit(), but not exec().

Since the things seem to work, I assume all callers are correct.  However,
drm_vbl_send_signals() looks broken.  block_all_signals() which is solely used
by drm is definitely broken.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>