fix group stop with exit race
do_signal_stop() counts all sub-thread and sets ->group_stop_count
accordingly. Every thread should decrement ->group_stop_count and stop,
the last one should notify the parent.
However a sub-thread can exit before it notices the signal_pending(), or it
may be somewhere in do_exit() already. In that case the group stop never
finishes properly.
Note: this is a minimal fix, we can add some optimizations later. Say we
can return quickly if thread_group_empty(). Also, we can move some signal
related code from exit_notify() to exit_signals().
Signed-off-by: Oleg Nesterov <[email protected]>
Acked-by: Davide Libenzi <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Roland McGrath <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
diff --git a/include/linux/signal.h b/include/linux/signal.h
index 7e09514..42d2e0a 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h
@@ -241,6 +241,7 @@
struct pt_regs;
extern int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka, struct pt_regs *regs, void *cookie);
+extern void exit_signals(struct task_struct *tsk);
extern struct kmem_cache *sighand_cachep;
