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Date: Tue, 09 Aug 2005 19:44:06 +0200
From: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
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To: linux-kernel@vger.kernel.org
Subject: Signal handling possibly wrong
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Hi,

reading man pages for sigaction and comparing it to what kernel does
when starting a signal handler (i386, s390, ppc and others), I think
one of both might be wrong.

 From man pages:

  sa_mask gives a mask of signals which should be blocked during
  execu­tion of the signal handler. In addition, the signal which
  triggered the handler will be blocked, unless the SA_NODEFER or
  SA_NOMASK flags are used.

 From arch/i386/kernel/signal.c:

         if (ret && !(ka->sa.sa_flags & SA_NODEFER)) {
                 spin_lock_irq(&current->sighand->siglock);
                 sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
                 sigaddset(&current->blocked,sig);
                 recalc_sigpending();
                 spin_unlock_irq(&current->sighand->siglock);
         }


If I understand man pages correctly, the handled signal should be blocked
depending on SA_NODEFER, while sa_mask should be used unconditionally to
block additional signals.
Kernel code blocks both "handled signal" _and_ sa_mask only if SA_NODEFER
isn't set.

Which is the right behavior?

Regards
		Bodo

P.S.:
Please CC me, I'm not on the list.