Re: [PATCH v8 5/8] seccomp: Add SECCOMP_RET_TRAP

From: Will Drewry
Date: Thu Feb 16 2012 - 16:33:49 EST


On Thu, Feb 16, 2012 at 3:28 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
> On 02/16/2012 12:42 PM, Will Drewry wrote:
>> On Thu, Feb 16, 2012 at 2:24 PM, Markus Gutschke <markus@xxxxxxxxxxxx> 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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