On Sun, 1 Oct 2017 21:20:28 +0000 (UTC) Julien Charbon <j...@freebsd.org> wrote:
> Author: jch > Date: Sun Oct 1 21:20:28 2017 > New Revision: 324179 > URL: https://svnweb.freebsd.org/changeset/base/324179 > > Log: > Fix an infinite loop in tcp_tw_2msl_scan() when an INP_TIMEWAIT inp has > been destroyed before its tcptw with INVARIANTS undefined. > > This is a symmetric change of r307551: > > A INP_TIMEWAIT inp should not be destroyed before its tcptw, and INVARIANTS > will catch this case. If INVARIANTS is undefined it will emit a > log(LOG_ERR) > and avoid a hard to debug infinite loop in tcp_tw_2msl_scan(). > > Reported by: Ben Rubson, hselasky > Submitted by: hselasky > Tested by: Ben Rubson, jch > MFC after: 1 week > Sponsored by: Verisign, inc > Differential Revision: https://reviews.freebsd.org/D12267 > > Modified: > head/sys/netinet/tcp_timewait.c > > Modified: head/sys/netinet/tcp_timewait.c > ============================================================================== > --- head/sys/netinet/tcp_timewait.c Sun Oct 1 20:12:30 2017 > (r324178) > +++ head/sys/netinet/tcp_timewait.c Sun Oct 1 21:20:28 2017 > (r324179) > @@ -709,10 +709,29 @@ tcp_tw_2msl_scan(int reuse) > INP_WLOCK(inp); > tw = intotw(inp); > if (in_pcbrele_wlocked(inp)) { > - KASSERT(tw == NULL, ("%s: held last inp " > - "reference but tw not NULL", __func__)); > - INP_INFO_RUNLOCK(&V_tcbinfo); > - continue; > + if (__predict_true(tw == NULL)) { > + INP_INFO_RUNLOCK(&V_tcbinfo); > + continue; > + } else { > + /* This should not happen as in TIMEWAIT > + * state the inp should not be destroyed > + * before its tcptw. If INVARIANTS is > + * defined panic. > + */ > +#ifdef INVARIANTS > + panic("%s: Panic before an infinite " > + "loop: INP_TIMEWAIT && (INP_FREED " > + "|| inp last reference) && tw != " > + "NULL", __func__); > +#else > + log(LOG_ERR, "%s: Avoid an infinite " > + "loop: INP_TIMEWAIT && (INP_FREED " > + "|| inp last reference) && tw != " > + "NULL", __func__); > +#endif > + INP_INFO_RUNLOCK(&V_tcbinfo); > + break; > + } > } > > if (tw == NULL) { > This file needs to include sys/syslog.h, otherwise LOG_ERR is not defined and the kernel build fails when INVARIANTS is not defined in the kernel config file. -- Gary Jennejohn _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
