Messages in this thread | | | Date | Tue, 2 Jun 2009 02:08:50 +0200 | From | Oleg Nesterov <> | Subject | Re: [PATCH] coredump: Retry writes where appropriate |
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On 06/01, Roland McGrath wrote: > > That is almost a separate subject, really. Having i/o calls' waits wrongly > interrupted and then clearing TIF_SIGPENDING just seems goofy to me.
Yes, agreed. The patch I sent make the coredumping task invisible to all signals except SIGKILL.
> But there is the possibility of recalc_sigpending_and_wake > via cancel_freezing, at least. Seems safer to make recalc_sigpending_tsk > robust in this case.
Oh, I forgot about freezer...
Well, not good to complicate recalc_sigpending_tsk() for this unlikely case. And this can't help, freezer does signal_wake_up() unconditionally.
So in fact this is another argument to check signal_pending() and clear it in dump_write/seek.
But since the coredumping task is not freezable anyway, perhaps we should change fake_signal_wake_up() to ignore SIGNAL_GROUP_DUMPING task.
Or we should make the coredumping freezable. This means dump_write/seek and exit_mm() should do try_to_freeze().
In any case, the coredumping is special. If ->write() returns -ERESTART/EINTR it assumes the return to ths user-space, this is not true for the coredump. This means that handling the spurious signals in coredump_file_write() is not so bad if we can't avoid this.
Oleg.
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