From: Ralf Baechle <ralf@linux-mips.org>
To: "Kevin D. Kissell" <kevink@paralogos.com>
Cc: Kaz Kylheku <KKylheku@zeugmasystems.com>, linux-mips@linux-mips.org
Subject: Re: Silly 100% CPU behavior on a SIG_IGN-ored SIGBUS.
Date: Thu, 25 Jun 2009 14:13:00 +0100 [thread overview]
Message-ID: <20090625131300.GB10661@linux-mips.org> (raw)
In-Reply-To: <4A415ACD.8010102@paralogos.com>
On Tue, Jun 23, 2009 at 03:44:29PM -0700, Kevin D. Kissell wrote:
>> int main(void)
>> {
>> int *deadbeef = (int *) 0xdeadbeef;
>> signal(SIGBUS, SIG_IGN);
>> printf("*deadbeef == %d\n", *deadbeef);
>> return 0;
>> }
>>
>> If any fatal exception is ignored, the program should be killed
>> if that exception happens. 100% CPU is not a useful response.
>>
> It's not a useful program, so what did you expect? One might argue
> that it would be more useful or correct to have the kernel advance the
> PC to not endlessly repeat the doomed load, but ignoring SIG_IGN and
> silently killing the thread violates the signal API as I've always
> understood it.
It's not a useful program but valid as a test case. However I agree with
your interpretation of signal semantics but I'll have to round up a copy
of the relevant standard documents; I have vague memories about some small
print for cases like this.
Ralf
next prev parent reply other threads:[~2009-06-25 13:17 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-23 21:45 Silly 100% CPU behavior on a SIG_IGN-ored SIGBUS Kaz Kylheku
2009-06-23 21:45 ` Kaz Kylheku
2009-06-23 22:03 ` David Daney
2009-06-25 3:39 ` Kaz Kylheku
2009-06-25 3:39 ` Kaz Kylheku
2009-06-23 22:44 ` Kevin D. Kissell
2009-06-25 13:13 ` Ralf Baechle [this message]
2009-06-25 13:45 ` Ralf Baechle
2009-06-25 16:00 ` Kaz Kylheku
2009-06-25 16:00 ` Kaz Kylheku
2009-06-26 0:45 ` Ralf Baechle
2009-06-26 0:52 ` David Daney
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