ptrace: introduce signal_wake_up_state() and ptrace_signal_wake_up()

commit 910ffdb18a6408e14febbb6e4b6840fd2c928c82 upstream.

Cleanup and preparation for the next change.

signal_wake_up(resume => true) is overused. None of ptrace/jctl callers
actually want to wakeup a TASK_WAKEKILL task, but they can't specify the
necessary mask.

Turn signal_wake_up() into signal_wake_up_state(state), reintroduce
signal_wake_up() as a trivial helper, and add ptrace_signal_wake_up()
which adds __TASK_TRACED.

This way ptrace_signal_wake_up() can work "inside" ptrace_request()
even if the tracee doesn't have the TASK_WAKEKILL bit set.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 1e86bb4..8204898 100644 (file)
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2597,7 +2597,16 @@ static inline void thread_group_cputime_init(struct signal_struct *sig)
 extern void recalc_sigpending_and_wake(struct task_struct *t);
 extern void recalc_sigpending(void);
 
-extern void signal_wake_up(struct task_struct *t, int resume_stopped);
+extern void signal_wake_up_state(struct task_struct *t, unsigned int state);
+
+static inline void signal_wake_up(struct task_struct *t, bool resume)
+{
+       signal_wake_up_state(t, resume ? TASK_WAKEKILL : 0);
+}
+static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume)
+{
+       signal_wake_up_state(t, resume ? __TASK_TRACED : 0);
+}
 
 /*
  * Wrappers for p->thread_info->cpu access. No-op on UP.

diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 78ab24a..77d7cac 100644 (file)
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -117,7 +117,7 @@ void __ptrace_unlink(struct task_struct *child)
         * TASK_KILLABLE sleeps.
         */
        if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child))
-               signal_wake_up(child, task_is_traced(child));
+               ptrace_signal_wake_up(child, true);
 
        spin_unlock(&child->sighand->siglock);
 }
@@ -307,7 +307,7 @@ static int ptrace_attach(struct task_struct *task, long request,
         */
        if (task_is_stopped(task) &&
            task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING))
-               signal_wake_up(task, 1);
+               signal_wake_up_state(task, __TASK_STOPPED);
 
        spin_unlock(&task->sighand->siglock);
 
@@ -736,7 +736,7 @@ int ptrace_request(struct task_struct *child, long request,
                 * tracee into STOP.
                 */
                if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))
-                       signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
+                       ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
 
                unlock_task_sighand(child, &flags);
                ret = 0;
@@ -762,7 +762,7 @@ int ptrace_request(struct task_struct *child, long request,
                         * start of this trap and now.  Trigger re-trap.
                         */
                        if (child->jobctl & JOBCTL_TRAP_NOTIFY)
-                               signal_wake_up(child, true);
+                               ptrace_signal_wake_up(child, true);
                        ret = 0;
                }
                unlock_task_sighand(child, &flags);

diff --git a/kernel/signal.c b/kernel/signal.c
index 08e0b97..389b366 100644 (file)
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -676,23 +676,17 @@ int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
  * No need to set need_resched since signal event passing
  * goes through ->blocked
  */
-void signal_wake_up(struct task_struct *t, int resume)
+void signal_wake_up_state(struct task_struct *t, unsigned int state)
 {
-       unsigned int mask;
-
        set_tsk_thread_flag(t, TIF_SIGPENDING);
-
        /*
-        * For SIGKILL, we want to wake it up in the stopped/traced/killable
+        * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
         * case. We don't check t->state here because there is a race with it
         * executing another processor and just now entering stopped state.
         * By using wake_up_state, we ensure the process will wake up and
         * handle its death signal.
         */
-       mask = TASK_INTERRUPTIBLE;
-       if (resume)
-               mask |= TASK_WAKEKILL;
-       if (!wake_up_state(t, mask))
+       if (!wake_up_state(t, state | TASK_INTERRUPTIBLE))
                kick_process(t);
 }
 
@@ -841,7 +835,7 @@ static void ptrace_trap_notify(struct task_struct *t)
        assert_spin_locked(&t->sighand->siglock);
 
        task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
-       signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
+       ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
 }
 
 /*