Date: Sun, 3 Feb 2008 18:29:18 +0200 From: Kostik Belousov <kostikbel@gmail.com> To: Peter Wemm <peter@wemm.org> Cc: Dag-Erling Sm?rgrav <des@des.no>, current@freebsd.org, threads@freebsd.org Subject: Re: Symbol versioning errors in libthr Message-ID: <20080203162918.GK57756@deviant.kiev.zoral.com.ua> In-Reply-To: <e7db6d980802030759x6db9bf1dq8992542bd8d2e017@mail.gmail.com> References: <861w7um5o5.fsf@ds4.des.no> <e7db6d980802030759x6db9bf1dq8992542bd8d2e017@mail.gmail.com>
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--7zUmpB12F58PluDH Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, Feb 03, 2008 at 08:59:45AM -0700, Peter Wemm wrote: > On Feb 3, 2008 8:16 AM, Dag-Erling Sm?rgrav <des@des.no> wrote: > > Here's an excerpt from the RELENG_7 vs HEAD diff of libthr's symbol map: > > > > --- pthread.map 13 May 2007 14:12:39 -0000 1.18 > > +++ pthread.map 20 Dec 2007 04:32:28 -0000 1.21 > > @@ -84,9 +84,13 @@ > > pthread_multi_np; > > pthread_mutex_destroy; > > pthread_mutex_getprioceiling; > > + pthread_mutex_getspinloops_np; > > + pthread_mutex_getyieldloops_np; > > pthread_mutex_init; > > pthread_mutex_lock; > > pthread_mutex_setprioceiling; > > + pthread_mutex_setspinloops_np; > > + pthread_mutex_setyieldloops_np; > > pthread_mutex_timedlock; > > pthread_mutex_trylock; > > pthread_mutex_unlock; > > > > These functions are all in FBSD_1.0, but they were introduced after the > > branch and never MFCed, so if I understand how we've implemented symbol > > versioning, they should be in FBSD_1.1. > > > > Unless someone argues credibly for keeping them in FBSD_1.0, I will move > > them to FBSD_1.1 in a few days. > > > > DES >=20 > I'm not sure I see the point in that. Consider the not-moving-to-1.1 > case. If somebody takes an 8.0 binary and runs it on 7.x, then > they'll get a 'symbol not found' error. On the other hand, if they're > moved and somebody tries the same thing, then they still get the same > kind of 'symbol not found' error but with just one character > different. Additional difference is that presence of the version itself is checked when the image is activated. This means that instead of abort in the middle of the execution since the rtld cannot find the symbol, the program gives error on the start.o AFAIR, this is original (Sun) usage of the versioning, before GNU extended it to allow individual version per symbol. I support DES to fix this in the proposed way. >=20 > The point of symbol versioning is to allow incompatible changes. eg: > to have a FBSD_1.0 version of pthread_mutex_getspinloops_np() *AND* a > FBSD_1.1 version of pthread_mutex_getspinloops_np() in the library > at the same time. The 1.0 instance would presumably be an API/ABI > conversion wrapper around the newer functions. >=20 > -Peter > --=20 > Peter Wemm - peter@wemm.org; peter@FreeBSD.org; peter@yahoo-inc.com > "All of this is for nothing if we don't go to the stars" - JMS/B5 > _______________________________________________ > freebsd-current@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org" --7zUmpB12F58PluDH Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.8 (FreeBSD) iEYEARECAAYFAkel694ACgkQC3+MBN1Mb4ihzACgvnTMAc/0gjdjkhDhixTUDjeM VxMAn3qV/+cKJoKpEAjs34uWT6+ySkc6 =glaa -----END PGP SIGNATURE----- --7zUmpB12F58PluDH--
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