Messages in this thread Patch in this message | | | From | Roland McGrath <> | Subject | [PATCH 17/23] tracehook: force signal_pending() | Date | Thu, 17 Jul 2008 00:30:50 -0700 (PDT) |
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This defines a new hook tracehook_force_sigpending() that lets tracing code decide to force TIF_SIGPENDING on in recalc_sigpending().
This is not used yet, so it compiles away to nothing for now. It lays the groundwork for new tracing code that can interrupt a task synthetically without actually sending a signal.
Signed-off-by: Roland McGrath <roland@redhat.com> --- include/linux/tracehook.h | 14 ++++++++++++++ kernel/signal.c | 4 +++- 2 files changed, 17 insertions(+), 1 deletions(-)
diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h index 4c50e1b..43bc51b 100644 --- a/include/linux/tracehook.h +++ b/include/linux/tracehook.h @@ -423,6 +423,20 @@ static inline int tracehook_consider_fatal_signal(struct task_struct *task, } /** + * tracehook_force_sigpending - let tracing force signal_pending(current) on + * + * Called when recomputing our signal_pending() flag. Return nonzero + * to force the signal_pending() flag on, so that tracehook_get_signal() + * will be called before the next return to user mode. + * + * Called with @current->sighand->siglock held. + */ +static inline int tracehook_force_sigpending(void) +{ + return 0; +} + +/** * tracehook_get_signal - deliver synthetic signal to traced task * @task: @current * @regs: task_pt_regs(@current) diff --git a/kernel/signal.c b/kernel/signal.c index cbec18e..44b5823 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -134,7 +134,9 @@ void recalc_sigpending_and_wake(struct task_struct *t) void recalc_sigpending(void) { - if (!recalc_sigpending_tsk(current) && !freezing(current)) + if (unlikely(tracehook_force_sigpending())) + set_thread_flag(TIF_SIGPENDING); + else if (!recalc_sigpending_tsk(current) && !freezing(current)) clear_thread_flag(TIF_SIGPENDING); }
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