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Date:	Tue, 23 Jun 2009 15:03:13 -0700
From:	David Daney <ddaney@caviumnetworks.com>
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To:	Kaz Kylheku <KKylheku@zeugmasystems.com>
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Subject: Re: Silly 100% CPU behavior on a SIG_IGN-ored SIGBUS.
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Kaz Kylheku wrote:
> Hi all,
> 
> On kernel 2.6.26, glibc 2.5 (n32), SiByte SB-1 core, the following
> program goes into 100% CPU, chewing up about 80% kernel time and
> 20% user.
> 
> #include <stdio.h>
> #include <signal.h>
> 
> 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.
> 
> (If there is a handler, and that handler returns without doing anything
> to
> prevent a recurrence of the exception when the instruction is re-tried,
> that's different).
> 
> 


I wonder if it is another instance of:

http://www.linux-mips.org/git?p=linux.git;a=commitdiff;h=49cf0e2d68dd98dbb28eaca0284e8460ab6ad86d

David Daney