diff options
| author | Oleg Nesterov <oleg@tv-sign.ru> | 2007-10-17 08:27:23 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-10-17 17:42:54 +0200 |
| commit | 6db840fa7887980ef68a649640d506fe069eef0c (patch) | |
| tree | 6248c1e65b572f1c2b14c46848e5a18df003f60e /kernel/exit.c | |
| parent | exec: consolidate 2 fast-paths (diff) | |
| download | linux-6db840fa7887980ef68a649640d506fe069eef0c.tar.xz linux-6db840fa7887980ef68a649640d506fe069eef0c.zip | |
exec: RT sub-thread can livelock and monopolize CPU on exec
de_thread() yields waiting for ->group_leader to be a zombie. This deadlocks
if an rt-prio execer shares the same cpu with ->group_leader. Change the code
to use ->group_exit_task/notify_count mechanics.
This patch certainly uglifies the code, perhaps someone can suggest something
better.
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>
Diffstat (limited to 'kernel/exit.c')
| -rw-r--r-- | kernel/exit.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/kernel/exit.c b/kernel/exit.c index 25f6805be5fe..4c108df88a37 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -92,10 +92,9 @@ static void __exit_signal(struct task_struct *tsk) * If there is any task waiting for the group exit * then notify it: */ - if (sig->group_exit_task && atomic_read(&sig->count) == sig->notify_count) { + if (sig->group_exit_task && atomic_read(&sig->count) == sig->notify_count) wake_up_process(sig->group_exit_task); - sig->group_exit_task = NULL; - } + if (tsk == sig->curr_target) sig->curr_target = next_thread(tsk); /* @@ -827,6 +826,11 @@ static void exit_notify(struct task_struct *tsk) state = EXIT_DEAD; tsk->exit_state = state; + if (thread_group_leader(tsk) && + tsk->signal->notify_count < 0 && + tsk->signal->group_exit_task) + wake_up_process(tsk->signal->group_exit_task); + write_unlock_irq(&tasklist_lock); list_for_each_safe(_p, _n, &ptrace_dead) { |