• Oleg Nesterov's avatar
    [PATCH] copy_process: cleanup bad_fork_cleanup_signal · 6b3934ef
    Oleg Nesterov authored
    __exit_signal() does important cleanups atomically under ->siglock.  It is
    also called from copy_process's error path.  This is not good, for example we
    can't move __unhash_process() under ->siglock for that reason.
    
    We should not mix these 2 paths, just look at ugly 'if (p->sighand)' under
    'bad_fork_cleanup_sighand:' label.  For copy_process() case it is sufficient
    to just backout copy_signal(), nothing more.
    
    Again, nobody can see this task yet.  For CLONE_THREAD case we just decrement
    signal->count, otherwise nobody can see this ->signal and we can free it
    lockless.
    
    This patch assumes it is safe to do exit_thread_group_keys() without
    tasklist_lock.
    Signed-off-by: default avatarOleg Nesterov <oleg@tv-sign.ru>
    Cc: "Eric W. Biederman" <ebiederm@xmission.com>
    Acked-by: default avatarDavid Howells <dhowells@redhat.com>
    Signed-off-by: default avatarAdrian Bunk <bunk@stusta.de>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
    6b3934ef
signal.c 70.1 KB