From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4E1C3A5D.3020700@domain.hid> Date: Tue, 12 Jul 2011 14:13:17 +0200 From: Jan Kiszka MIME-Version: 1.0 References: <4E1B469A.8000703@domain.hid> <4E1B4AC0.80506@domain.hid> <4E1B4C19.2070205@domain.hid> <4E1B542B.2010906@domain.hid> <4E1B5638.1050005@domain.hid> <4E1B56E0.20109@domain.hid> <4E1B57D1.1070401@domain.hid> <4E1B5860.1000309@domain.hid> <4E1B5944.5030408@domain.hid> <4E1BEC9F.1020404@domain.hid> <4E1BF619.6010609@domain.hid> <4E1C2912.9050605@domain.hid> <4E1C2959.8080004@domain.hid> <4E1C2A2D.9090602@domain.hid> <4E1C2AA5.6060208@domain.hid> <4E1C2B44.5060907@domain.hid> <4E1C2B8F.5080700@domain.hid> <4E1C2F56.8020103@domain.hid> <4E1C302A.8050309@domain.hid> <4E1C3301.2030203@domain.hid> <4E1C3672.1030104@domain.hid> <4E1C36EE.70803@domain.hid> <4E1C38CE.7090202@domain.hid> In-Reply-To: <4E1C38CE.7090202@domain.hid> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enigCE66A0B69A8817B981FB0FFF" Sender: jan.kiszka@domain.hid Subject: Re: [Xenomai-core] [Xenomai-git] Jan Kiszka : nucleus: Fix race between gatekeeper and thread deletion List-Id: Xenomai life and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gilles Chanteperdrix Cc: Xenomai core This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigCE66A0B69A8817B981FB0FFF Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 2011-07-12 14:06, Gilles Chanteperdrix wrote: > On 07/12/2011 01:58 PM, Jan Kiszka wrote: >> On 2011-07-12 13:56, Jan Kiszka wrote: >>> However, this parallel unsynchronized execution of the gatekeeper and= >>> its target thread leaves an increasingly bad feeling on my side. Did = we >>> really catch all corner cases now? I wouldn't guarantee that yet. >>> Specifically as I still have an obscure crash of a Xenomai thread on >>> Linux schedule() on my table. >>> >>> What if the target thread woke up due to a signal, continued much >>> further on a different CPU, blocked in TASK_INTERRUPTIBLE, and then t= he >>> gatekeeper continued? I wish we could already eliminate this complexi= ty >>> and do the migration directly inside schedule()... >> >> BTW, we do we mask out TASK_ATOMICSWITCH when checking the task state = in >> the gatekeeper? What would happen if we included it (state =3D=3D >> (TASK_ATOMICSWITCH | TASK_INTERRUPTIBLE))? >=20 > I would tend to think that what we should check is > xnthread_test_info(XNATOMIC). Or maybe check both, the interruptible > state and the XNATOMIC info bit. Actually, neither the info bits nor the task state is sufficiently synchronized against the gatekeeper yet. We need to hold a shared lock when testing and resetting the state. I'm not sure yet if that is fixable given the gatekeeper architecture. Jan --------------enigCE66A0B69A8817B981FB0FFF Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.16 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAk4cOl0ACgkQitSsb3rl5xQFsQCfW2C00GBBmRBjTE+X94rLFv/b OUIAoJ8EXPAQWd+ylUZ1YGfhcex4Aas4 =hycL -----END PGP SIGNATURE----- --------------enigCE66A0B69A8817B981FB0FFF--