Messages in this thread | | | Date | Thu, 26 Apr 2012 16:31:19 +0200 | From | Martin Schwidefsky <> | Subject | Re: [RFC] TIF_NOTIFY_RESUME, arch/*/*/*signal*.c and all such |
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On Thu, 26 Apr 2012 15:52:55 +0200 Oleg Nesterov <oleg@redhat.com> wrote:
> On 04/26, Martin Schwidefsky wrote: > > You need to be careful with inferior calls there. gdb likes to play games > > with the registers inside the get_signal_to_deliver call, it wants to be > > able to jump out of an interrupted system call, do its inferior call in > > the debugee and then return to the interrupted system call. > > Ah. > > > You would have to to read, modify & restore the NEED_RESTART flag in gdb > > over an inferior call. > > I am not sure, but perhaps this is not really needed... > > But at least this means that "if (we have any business doing restarts)" > above is meaningless before get_signal_to_deliver(). > > > And I am confused, off-topic question... How it is possible to > "then return to the interrupted system call" if that system call > returned -ERESTART_RESTARTBLOCK but the inferior call in turn > does the system call which changes restart_block->fn/etc ?
Returning from an inferior gdb call to a system call that needs to be restarted with -ERESTART_RESTARTBLOCK is broken on all architectures as far as I can tell. And it would be hard to fix it, basically you have to save and restore the restart block.
-- blue skies, Martin.
"Reality continues to ruin my life." - Calvin.
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