ptrace: introduce signal_wake_up_state() and ptrace_signal_wake_up()

Upstream commit 910ffdb18a6408e14febbb6e4b6840fd2c928c82.

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: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 0dae42e..d728bab 100644 (file)
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2564,7 +2564,16 @@ 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 2df1157..d77fa9e 100644 (file)
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -92,7 +92,7 @@ void __ptrace_unlink(struct task_struct *child)
         * TASK_KILLABLE sleeps.
         */
        if (child->group_stop & GROUP_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);
 }
@@ -245,7 +245,7 @@ static int ptrace_attach(struct task_struct *task)
         */
        if (task_is_stopped(task)) {
                task->group_stop |= GROUP_STOP_PENDING | GROUP_STOP_TRAPPING;
-               signal_wake_up(task, 1);
+               signal_wake_up_state(task, __TASK_STOPPED);
                wait_trap = true;
        }
 

diff --git a/kernel/signal.c b/kernel/signal.c
index 43fee1c..8b0dd5b 100644 (file)
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -631,23 +631,17 @@ 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);
 }