diff options
| author | Roland McGrath <roland@redhat.com> | 2008-07-25 19:45:55 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-07-26 12:00:09 -0700 |
| commit | b787f7ba677840da16a2228c16571ce8a1fcb799 (patch) | |
| tree | b1838c4ae7f38c00efc2375871a255275500f245 | |
| parent | 2b2a1ff64afbadac842bbc58c5166962cf4f7664 (diff) | |
tracehook: force signal_pending()
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>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | include/linux/tracehook.h | 14 | ||||
| -rw-r--r-- | kernel/signal.c | 4 |
2 files changed, 17 insertions, 1 deletions
diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h index 4c50e1b5734..43bc51b6bd3 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 0e862d3130f..954f77d7e3b 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); } |