diff options
Diffstat (limited to 'kernel/signal.c')
-rw-r--r-- | kernel/signal.c | 92 |
1 files changed, 38 insertions, 54 deletions
diff --git a/kernel/signal.c b/kernel/signal.c index 3fd2ce133387..d2d0c753156c 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2187,13 +2187,12 @@ static void do_notify_parent_cldstop(struct task_struct *tsk, * with. If the code did not stop because the tracer is gone, * the stop signal remains unchanged unless clear_code. */ -static int ptrace_stop(int exit_code, int why, int clear_code, - unsigned long message, kernel_siginfo_t *info) +static int ptrace_stop(int exit_code, int why, unsigned long message, + kernel_siginfo_t *info) __releases(¤t->sighand->siglock) __acquires(¤t->sighand->siglock) { bool gstop_done = false; - bool read_code = true; if (arch_ptrace_stop_needed()) { /* @@ -2212,7 +2211,14 @@ static int ptrace_stop(int exit_code, int why, int clear_code, /* * schedule() will not sleep if there is a pending signal that * can awaken the task. + * + * After this point ptrace_signal_wake_up will clear TASK_TRACED + * if ptrace_unlink happens. Handle previous ptrace_unlinks + * here to prevent ptrace_stop sleeping in schedule. */ + if (!current->ptrace) + return exit_code; + set_special_state(TASK_TRACED); /* @@ -2259,54 +2265,33 @@ static int ptrace_stop(int exit_code, int why, int clear_code, spin_unlock_irq(¤t->sighand->siglock); read_lock(&tasklist_lock); - if (likely(current->ptrace)) { - /* - * Notify parents of the stop. - * - * While ptraced, there are two parents - the ptracer and - * the real_parent of the group_leader. The ptracer should - * know about every stop while the real parent is only - * interested in the completion of group stop. The states - * for the two don't interact with each other. Notify - * separately unless they're gonna be duplicates. - */ + /* + * Notify parents of the stop. + * + * While ptraced, there are two parents - the ptracer and + * the real_parent of the group_leader. The ptracer should + * know about every stop while the real parent is only + * interested in the completion of group stop. The states + * for the two don't interact with each other. Notify + * separately unless they're gonna be duplicates. + */ + if (current->ptrace) do_notify_parent_cldstop(current, true, why); - if (gstop_done && ptrace_reparented(current)) - do_notify_parent_cldstop(current, false, why); + if (gstop_done && (!current->ptrace || ptrace_reparented(current))) + do_notify_parent_cldstop(current, false, why); - /* - * Don't want to allow preemption here, because - * sys_ptrace() needs this task to be inactive. - * - * XXX: implement read_unlock_no_resched(). - */ - preempt_disable(); - read_unlock(&tasklist_lock); - cgroup_enter_frozen(); - preempt_enable_no_resched(); - freezable_schedule(); - cgroup_leave_frozen(true); - } else { - /* - * By the time we got the lock, our tracer went away. - * Don't drop the lock yet, another tracer may come. - * - * If @gstop_done, the ptracer went away between group stop - * completion and here. During detach, it would have set - * JOBCTL_STOP_PENDING on us and we'll re-enter - * TASK_STOPPED in do_signal_stop() on return, so notifying - * the real parent of the group stop completion is enough. - */ - if (gstop_done) - do_notify_parent_cldstop(current, false, why); - - /* tasklist protects us from ptrace_freeze_traced() */ - __set_current_state(TASK_RUNNING); - read_code = false; - if (clear_code) - exit_code = 0; - read_unlock(&tasklist_lock); - } + /* + * Don't want to allow preemption here, because + * sys_ptrace() needs this task to be inactive. + * + * XXX: implement read_unlock_no_resched(). + */ + preempt_disable(); + read_unlock(&tasklist_lock); + cgroup_enter_frozen(); + preempt_enable_no_resched(); + freezable_schedule(); + cgroup_leave_frozen(true); /* * We are back. Now reacquire the siglock before touching @@ -2314,8 +2299,7 @@ static int ptrace_stop(int exit_code, int why, int clear_code, * any signal-sending on another CPU that wants to examine it. */ spin_lock_irq(¤t->sighand->siglock); - if (read_code) - exit_code = current->exit_code; + exit_code = current->exit_code; current->last_siginfo = NULL; current->ptrace_message = 0; current->exit_code = 0; @@ -2343,7 +2327,7 @@ static int ptrace_do_notify(int signr, int exit_code, int why, unsigned long mes info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); /* Let the debugger run. */ - return ptrace_stop(exit_code, why, 1, message, &info); + return ptrace_stop(exit_code, why, message, &info); } int ptrace_notify(int exit_code, unsigned long message) @@ -2515,7 +2499,7 @@ static void do_jobctl_trap(void) CLD_STOPPED, 0); } else { WARN_ON_ONCE(!signr); - ptrace_stop(signr, CLD_STOPPED, 0, 0, NULL); + ptrace_stop(signr, CLD_STOPPED, 0, NULL); } } @@ -2568,7 +2552,7 @@ static int ptrace_signal(int signr, kernel_siginfo_t *info, enum pid_type type) * comment in dequeue_signal(). */ current->jobctl |= JOBCTL_STOP_DEQUEUED; - signr = ptrace_stop(signr, CLD_TRAPPED, 0, 0, info); + signr = ptrace_stop(signr, CLD_TRAPPED, 0, info); /* We're back. Did the debugger cancel the sig? */ if (signr == 0) |