diff options
Diffstat (limited to 'kernel/signal.c')
| -rw-r--r-- | kernel/signal.c | 35 |
1 files changed, 30 insertions, 5 deletions
diff --git a/kernel/signal.c b/kernel/signal.c index 1b3c921737e2..52adf53929f6 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1531,6 +1531,35 @@ static void do_notify_parent_cldstop(struct task_struct *tsk, int why) spin_unlock_irqrestore(&sighand->siglock, flags); } +static inline int may_ptrace_stop(void) +{ + if (!likely(current->ptrace & PT_PTRACED)) + return 0; + + if (unlikely(current->parent == current->real_parent && + (current->ptrace & PT_ATTACHED))) + return 0; + + if (unlikely(current->signal == current->parent->signal) && + unlikely(current->signal->flags & SIGNAL_GROUP_EXIT)) + return 0; + + /* + * Are we in the middle of do_coredump? + * If so and our tracer is also part of the coredump stopping + * is a deadlock situation, and pointless because our tracer + * is dead so don't allow us to stop. + * If SIGKILL was already sent before the caller unlocked + * ->siglock we must see ->core_waiters != 0. Otherwise it + * is safe to enter schedule(). + */ + if (unlikely(current->mm->core_waiters) && + unlikely(current->mm == current->parent->mm)) + return 0; + + return 1; +} + /* * This must be called with current->sighand->siglock held. * @@ -1559,11 +1588,7 @@ static void ptrace_stop(int exit_code, int nostop_code, siginfo_t *info) spin_unlock_irq(¤t->sighand->siglock); try_to_freeze(); read_lock(&tasklist_lock); - if (likely(current->ptrace & PT_PTRACED) && - likely(current->parent != current->real_parent || - !(current->ptrace & PT_ATTACHED)) && - (likely(current->parent->signal != current->signal) || - !unlikely(current->signal->flags & SIGNAL_GROUP_EXIT))) { + if (may_ptrace_stop()) { do_notify_parent_cldstop(current, CLD_TRAPPED); read_unlock(&tasklist_lock); schedule(); |