Date: Thu, 11 Jun 2015 09:18:07 -0400 From: Julien Charbon <jch@freebsd.org> To: John Baldwin <jhb@FreeBSD.org>, src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r284245 - head/sys/netinet Message-ID: <55798A8F.3080308@freebsd.org> In-Reply-To: <5578ACEC.2070209@FreeBSD.org> References: <201506102043.t5AKh8YB058825@svn.freebsd.org> <5578ACEC.2070209@FreeBSD.org>
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This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --WHPKl0evAFXGXOSuORv2QMg5aobn7U5eH Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Hi John, On 10/06/15 17:32, John Baldwin wrote: > On 6/10/15 4:43 PM, Julien Charbon wrote: >> Author: jch >> Date: Wed Jun 10 20:43:07 2015 >> New Revision: 284245 >> URL: https://svnweb.freebsd.org/changeset/base/284245 >> >> Log: >> Fix a callout race condition introduced in TCP timers callouts with = r281599. >> In TCP timer context, it is not enough to check callout_stop() retur= n value >> to decide if a callout is still running or not, previous callout_res= et() >> return values have also to be checked. >> =20 >> Differential Revision: https://reviews.freebsd.org/D2763 >> Reviewed by: hiren >> Approved by: hiren >> MFC after: 1 day >> Sponsored by: Verisign, Inc. >> >> Modified: >> head/sys/netinet/tcp_timer.c >> head/sys/netinet/tcp_timer.h >> >> Modified: head/sys/netinet/tcp_timer.c >> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D >> --- head/sys/netinet/tcp_timer.c Wed Jun 10 20:11:28 2015 (r284244) >> +++ head/sys/netinet/tcp_timer.c Wed Jun 10 20:43:07 2015 (r284245) >> @@ -347,11 +347,12 @@ tcp_timer_2msl(void *xtp) >> tp =3D tcp_close(tp); =20 >> } else { >> if (tp->t_state !=3D TCPS_TIME_WAIT && >> - ticks - tp->t_rcvtime <=3D TP_MAXIDLE(tp)) >> - callout_reset_on(&tp->t_timers->tt_2msl, >> - TP_KEEPINTVL(tp), tcp_timer_2msl, tp, >> - inp_to_cpuid(inp)); >> - else >> + ticks - tp->t_rcvtime <=3D TP_MAXIDLE(tp)) { >> + if (!callout_reset(&tp->t_timers->tt_2msl, >> + TP_KEEPINTVL(tp), tcp_timer_2msl, tp)) { >> + tp->t_timers->tt_flags &=3D ~TT_2MSL_RST; >> + } >> + } else >> tp =3D tcp_close(tp); >=20 > Did you mean to use callout_reset() instead of callout_reset_on() here = and > elsewhere in this change? Thanks for this question. Exactly, the goal here is to make clear that once a TCP timer callout is scheduled on a core, we always reset this callout on the same core. It was already the case before, but having only one callout_reset_on() call in tcp_timer_activate() when we start callout the first time, and callout_reset() calls everywhere else make it (hopefully) clearer. My 2 cents. -- Julien --WHPKl0evAFXGXOSuORv2QMg5aobn7U5eH Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Comment: GPGTools - https://gpgtools.org iQEcBAEBCgAGBQJVeYqYAAoJEKVlQ5Je6dhx400H/20EQhfM69CwW5ZmhYHGhCTg cfubDWC9tfm5ipd6nzPw1Fp0ILp0Lk/BGvp0q7dFbY35kt5aRBbiY6sV7W6GJrge Vf0g5zA06M37vHGZ8MK5GXcynWfX4GaXfvIvd99WLg4Hwj77YZLyMFSBfBFYA7be IvDJ956k3fc9w7wve5RUgkXgAXCiedsJQYDxZlUMb9FgUq23qQpTup+Gnc36t4qa X8YWrQuMJhbP59/hCcp3jRfqy8dEpbLSO44SiKQlcSCPZ7OYiODKgK2lobO9YXqA EklPVNiWVEPiIPmoKUYayrNSGoGKvcB8CwFPzZ3XM5IzluG1W5n+O6Xl0jT9UBQ= =L5Rs -----END PGP SIGNATURE----- --WHPKl0evAFXGXOSuORv2QMg5aobn7U5eH--
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