On Thu, May 01, 2008 at 11:33:34AM -0500, Kumar Gala wrote:

Let me ask the question differently.  Are there cases that some event  
occurs in the system and a signal is delivered to the current process  
regardless of what that process is.

Yes, timers that expire based on CPU usage.

 I'm guessing so, based on the tty example.

I don't think tty interrupts would -- it'd go to the process group
associated with the tty.

So for the specific case I'm looking at (kprobes & debug exceptions  
from kernel space), I think its reasonable to BUG_ON() if thread_info- 

quoted

flags changes such that TIF_SIGPENDING or TIF_NEED_RESCHED get set  

we aren't from user-space.

Why?  It may not happen currently, but it seems more future-proof to just
copy the flags.  And it's certainly not reasonable for normal interrupts.

-Scott