On 05/29, Roland McGrath wrote: > > Your fix seems like the only way to go. From skimming all the ERESTART* > uses, I think that in all cases (except for n_tty.c:job_control before your > patch), TIF_SIGPENDING is indeed set when a thread returns -ERESTART*. > > But it makes me realize that there is a danger of leaking a -ERESTART* > return code to userland when TIF_SIGPENDING gets cleared by another thread > doing a recalc_sigpending_tsk. Because of -ERESTART* I think we must make > it a rule that no thread can clear another thread's TIF_SIGPENDING, only > set it (unless it's known to be stopped in the signal code or something). > >From our recent work on it, I think that do_sigaction is in fact the only > place this can happen. So that says we should err in the other direction > from what I said before in do_sigaction, and not have it do recalc at all.
I think you are right. But please note that cancel_freezing(p) is special. It is also called when try_to_freeze_tasks() fails. So it should clear TIF_SIGPENDING if "p" is a kernel thread, otherwise p may run with signal_pending() forever. Unfortunately, it is not easy to detect the kernel thread, is_user_space() is not reliable. Probably we should ignore this minor problem and do not change cancel_freezing(). Oleg. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
