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Date: Thu, 16 Feb 2012 15:33:47 -0600
Message-ID: <CABqD9hbW_z-x7tgnBHPqVry=XLo+HDFtAhdXKHG+fxgn6fB6_g@mail.gmail.com>
Subject: Re: [PATCH v8 5/8] seccomp: Add SECCOMP_RET_TRAP
From: Will Drewry <wad@chromium.org>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Markus Gutschke <markus@chromium.org>, linux-kernel@vger.kernel.org,
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On Thu, Feb 16, 2012 at 3:28 PM, H. Peter Anvin <hpa@zytor.com> wrote:
> On 02/16/2012 12:42 PM, Will Drewry wrote:
>> On Thu, Feb 16, 2012 at 2:24 PM, Markus Gutschke <markus@chromium.org> wrote:
>>> SIGTRAP might not be the ideal choice of signal number, as it can make it
>>> very difficult to debug the program in gdb.
>>
>> True enough. ?In theory, we could use the lower 16-bits of the return
>> value to let the bpf program set a signal, but not all signals are
>> masked synchronous and those that are probably get gdb's attention,
>> just not a severely :) (ILL, SEGV, BUS, TRAP, FPE). Perhaps SIGILL is
>> a logically appropriate option -- or letting the api user decide from
>> the SYNCHRONOUS_MASK set. ?I'm open to whatever makes sense, though.
>> (I wasn't even sure if it was kosher to add a new TRAP_SECCOMP value.)
>>
>
> There is a standard signal for this -- SIGSYS -- which happens to be
> currently unused in Linux.

Awesome.  I'll respin using that.
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