Date: Fri, 7 Sep 2012 23:35:15 +0100 From: Attilio Rao <attilio@freebsd.org> To: Andriy Gapon <avg@freebsd.org> Cc: Konstantin Belousov <kostikbel@gmail.com>, Davide Italiano <davide@freebsd.org>, src-committers@freebsd.org, svn-src-projects@freebsd.org Subject: Re: svn commit: r238907 - projects/calloutng/sys/kern Message-ID: <CAJ-FndDAFmrEBW3d29cj-CZoPT%2BD5UPFadzL6i9BNH9ztzsJ%2BQ@mail.gmail.com> In-Reply-To: <CAJ-FndB0zc-TC0E=H4p1qcOB4ngEWtwXoyhScf68G8i0p5UErw@mail.gmail.com> References: <201207301350.q6UDobCI099069@svn.freebsd.org> <CAJ-FndBJNNBNDUEDsDBUvwoVExZpnXmoJmpY58gE3QQbw3hRGA@mail.gmail.com> <CACYV=-HmOwZ=E8Pw3-mUw0994SbvZaA3eMfcwM0fDTu_zykBJg@mail.gmail.com> <CAJ-FndBmXkyJJ=fCkEpVm84E56A2_EoM6kbch03e4RMEM6WCGQ@mail.gmail.com> <20120730143943.GY2676@deviant.kiev.zoral.com.ua> <CAJ-FndByYcZ%2BUhnkFT_n2=W=UheqUCi0%2BUAX%2BF07EqbVU=6iDQ@mail.gmail.com> <CAJ-FndCQ6HGAfFdjofNfJ%2BHeNaE7uqoNhJB9GH4pGFxyZ_1yLg@mail.gmail.com> <5016A21B.6090409@FreeBSD.org> <CAJ-FndCFjZP=0ThpMxy6WSDQAZOm0TRkyu0bWfxVBwtT-h%2B1cA@mail.gmail.com> <5016A8E4.7070405@FreeBSD.org> <CAJ-FndB0zc-TC0E=H4p1qcOB4ngEWtwXoyhScf68G8i0p5UErw@mail.gmail.com>
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On Mon, Jul 30, 2012 at 9:39 PM, Attilio Rao <attilio@freebsd.org> wrote: > On Mon, Jul 30, 2012 at 4:31 PM, Andriy Gapon <avg@freebsd.org> wrote: >> on 30/07/2012 18:04 Attilio Rao said the following: >>> On 7/30/12, Andriy Gapon <avg@freebsd.org> wrote: >>>> on 30/07/2012 17:56 Attilio Rao said the following: >>>>> More explicitly, I think such combination TDP_NOSLEEPING + >>>>> TDP_NOBLOCKING (name invented) should be set on entering the interrupt >>>>> context, not only related to this part of callouts. This would be a >>>>> very good help for catching buggy situations. >>>> >>>> Something very tangential. I think it would also be nice to check if a >>>> thread has >>>> any(?) locks held when returning to userland. >>> >>> This happens already for INVARIANTS case, with td_locks counters. >>> In the !INVARIANTS case, this doesn't happen because you don't want to >>> add the burden to bump td_locks for the fast case and I think it is a >>> good approach. >> >> Ah, I missed that, thank you. >> BTW, it seems that td_locks is checked twice in normal syscallret() path: once in >> syscallret() itself and then in userret(). On this note, would it make sense to >> move the whole nine yards of asserts from syscallret() to userret()? >> I mean it might make sense to have those checks (td_critnest, td_pflags) in other >> paths to userland. > > Nice catch. > The checks were added to syscallret() in r208453. While this is fine, > I think that putting them in userret() may give them more exposure and > cover also cases like traps which are not covered right now. > If you want to make a patch that moves these conditions in userret() > I'd be in favor of it. More specifically, what do you think about this patch?: http://www.freebsd.org/~attilio/userret_diag.patch Of course I moved the XEN par too before the checks. The patch survived to few consecutive and parallel buildworlds, FWIW. Attilio -- Peace can only be achieved by understanding - A. Einstein
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