tile: do_hardwall_trap: do not play with task->sighand

Quoted 6 lines · Oleg Nesterov

Hmm. It turns out, I can't make the patch because I do not understand what this code tries to do.

hardwall_activate() adds the thread to hardwall_list, but do_hardwall_trap() sends the signal to the whole process. I know nothing about arch/tile and probably this is correct, but could you confirm this?

Yes, the intended behavior is to send the signal to the process, as a way of indicating the OS's displeasure with sending a malformed packet on the user network. But I think sending it to the specific thread is reasonable too; I don't have a strong preference in this design.

Quoted 5 lines

Note that SIGILL can be delivered to another thread in the thread-group, is it correct?

Also. Is it supposed that SIGILL can have a hanlder or can be blocked, or it should always kill the whole thread group?

A handler would be reasonable for the process.

Quoted 2 lines

I think we need the patch below, assuming that SIGILL should be sent to the single thread and it is fine to have a handler for SIGILL.

Thanks; I appreciate the additional code review in any case. I'll look at the ramifications of the change in more detail when I return from vacation late next week.