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Date:   Wed, 29 May 2013 19:36:34 +0200
From:   Oleg Nesterov <oleg@redhat.com>
To:     David Daney <ddaney.cavm@gmail.com>
Cc:     James Hogan <james.hogan@imgtec.com>, linux-kernel@vger.kernel.org,
        linux-mips@linux-mips.org, Ralf Baechle <ralf@linux-mips.org>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Andrew Morton <akpm@linux-foundation.org>,
        Kees Cook <keescook@chromium.org>
Subject: Re: [RFC PATCH] kernel/signal.c: avoid BUG_ON with SIG128 (MIPS)
Message-ID: <20130529173634.GA2020@redhat.com>
References: <1369846916-13202-1-git-send-email-james.hogan@imgtec.com> <51A638A4.2000705@gmail.com>
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On 05/29, David Daney wrote:
>
> On 05/29/2013 10:01 AM, James Hogan wrote:
>> MIPS has 128 signals, the highest of which has the number 128. The
>
> I wonder if we should change the ABI and reduce the number of signals to
> 127 instead of this patch.

Same thoughts...

>> @@ -2366,8 +2366,12 @@ relock:
>>
>>   		/*
>>   		 * Death signals, no core dump.
>> +		 *
>> +		 * MIPS has a signal number 128 which clashes with the core dump
>> +		 * bit. If this was the signal we still want to report a valid
>> +		 * exit code, so round it down to 127.
>>   		 */
>> -		do_group_exit(info->si_signo);
>> +		do_group_exit(min(info->si_signo, 127));

This avoids BUG_ON() but obviously fools WIFSIGNALED(), doesn't look
very nice.

Oleg.