1. 08 Oct, 2005 2 commits
    • David Vrabel's avatar
      [PATCH] yenta: fix build if YENTA && !CARDBUS · c2059b2e
      David Vrabel authored
      (struct pcmcia_socket).tune_bridge only exists if CONFIG_CARDBUS is set
      but building yenta_socket without CardBus is valid.
      Signed-off-by: default avatarDavid Vrabel <dvrabel@arcom.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      c2059b2e
    • Oleg Nesterov's avatar
      [PATCH] fix do_coredump() vs SIGSTOP race · 788e05a6
      Oleg Nesterov authored
      Let's suppose we have 2 threads in thread group:
      	A - does coredump
      	B - has pending SIGSTOP
      
      thread A						thread B
      
      do_coredump:						get_signal_to_deliver:
      
        lock(->sighand)
        ->signal->flags = SIGNAL_GROUP_EXIT
        unlock(->sighand)
      
      							lock(->sighand)
      							signr = dequeue_signal()
      								->signal->flags |= SIGNAL_STOP_DEQUEUED
      								return SIGSTOP;
      
      							do_signal_stop:
      							    unlock(->sighand)
      
        coredump_wait:
      
            zap_threads:
                lock(tasklist_lock)
                send SIGKILL to B
                    // signal_wake_up() does nothing
                unlock(tasklist_lock)
      
      							    lock(tasklist_lock)
      							    lock(->sighand)
      							    re-check sig->flags & SIGNAL_STOP_DEQUEUED, yes
      							    set_current_state(TASK_STOPPED);
      							    finish_stop:
      							        schedule();
      							            // ->state == TASK_STOPPED
      
            wait_for_completion(&startup_done)
               // waits for complete() from B,
               // ->state == TASK_UNINTERRUPTIBLE
      
      We can't wake up 'B' in any way:
      
      	SIGCONT will be ignored because handle_stop_signal() sees
      	->signal->flags & SIGNAL_GROUP_EXIT.
      
      	sys_kill(SIGKILL)->__group_complete_signal() will choose
      	uninterruptible 'A', so it can't help.
      
      	sys_tkill(B, SIGKILL) will be ignored by specific_send_sig_info()
      	because B already has pending SIGKILL.
      
      This scenario is not possbile if 'A' does do_group_exit(), because
      it sets sig->flags = SIGNAL_GROUP_EXIT and delivers SIGKILL to
      subthreads atomically, holding both tasklist_lock and sighand->lock.
      That means that do_signal_stop() will notice !SIGNAL_STOP_DEQUEUED
      after re-locking ->sighand. And it is not possible to any other
      thread to re-add SIGNAL_STOP_DEQUEUED later, because dequeue_signal()
      can only return SIGKILL.
      
      I think it is better to change do_coredump() to do sigaddset(SIGKILL)
      and signal_wake_up() under sighand->lock, but this patch is much
      simpler.
      Signed-off-by: default avatarOleg Nesterov <oleg@tv-sign.ru>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      788e05a6
  2. 07 Oct, 2005 1 commit
  3. 06 Oct, 2005 7 commits
  4. 05 Oct, 2005 22 commits
  5. 04 Oct, 2005 8 commits