Re: PR/52117 CVS commit: src/tests/kernel

[Kamil Rytarowski <n54%gmx.com@localhost>]

The following reply was made to PR kern/52117; it has been noted by GNATS.

From: Kamil Rytarowski <n54%gmx.com@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: 
Subject: Re: PR/52117 CVS commit: src/tests/kernel
Date: Wed, 29 Mar 2017 07:03:41 +0200

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 From: Kamil Rytarowski <n54%gmx.com@localhost>
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 Subject: Re: PR/52117 CVS commit: src/tests/kernel
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 On 29.03.2017 06:55, Martin Husemann wrote:
 > The following reply was made to PR kern/52117; it has been noted by GNA=
 TS.
 >=20
 > From: Martin Husemann <martin%duskware.de@localhost>
 > To: gnats-bugs%NetBSD.org@localhost
 > Cc:=20
 > Subject: Re: PR/52117 CVS commit: src/tests/kernel
 > Date: Wed, 29 Mar 2017 06:52:21 +0200
 >=20
 >  On Tue, Mar 28, 2017 at 09:40:00PM +0000, Kamil Rytarowski wrote:
 >  >  For consistency I would add "ksi.ksi_signo =3D TRAP_CHLD;". My moti=
 vation
 >  >  is to attribute every SIGTRAP in the kernel with appropriate si_cod=
 e,
 >  >  even if it works for some reasons in some scenarios without them.
 > =20
 >  Yes, that certainly should be done.
 > =20
 >  >  From user-space point of view we want a deterministic order of rece=
 iving
 >  >  signals by a debugger. Signal for "child" and next "child2".
 > =20
 >  We can not guarantee this. The signals happen as soon as the process
 >  gets scheduled, it would be pretty hard to guarantee the forker runnin=
 g
 >  first (at least I wouldn't know how to do that).
 > =20
 >  Is this realy a requirement from a debuggers perspective?
 > =20
 
 No, it's not a hard requirement. It's in the class of nice-to-have to
 make the code inside a debugger simpler. Random order in Linux is making
 trouble for the designers of debuggers, but since we generate TRAP_CHLD
 this is already mitigated.
 
 We need to alter documentation and ATF tests for this.
 
 >  >  I prefer the <sys/childreturn.h> version as it has bit less overhea=
 d...
 >  >  but it might be just a microoptimization not worth modifying the
 >  >  child_return code in all ports.
 > =20
 >  Yes, the code is a bit clunky, but runtime performance and locking is =
 actually
 >  better (I think).
 > =20
 
 I think we can go this route. Thank you for your patch.
 
 >  Martin
 > =20
 >=20
 
 
 
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