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

From: H. Peter Anvin
Date: Thu Feb 16 2012 - 16:29:50 EST


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.

-hpa

--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.

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