Date: Thu, 4 Oct 2018 22:03:58 +0000 (UTC) From: Ryan Stone <rstone@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r339185 - head/sys/netinet Message-ID: <201810042203.w94M3wq1001668@repo.freebsd.org>
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Author: rstone Date: Thu Oct 4 22:03:58 2018 New Revision: 339185 URL: https://svnweb.freebsd.org/changeset/base/339185 Log: Hold a write lock across udp_notify() With the new route cache feature udp_notify() will modify the inp when it needs to invalidate the route cache. Ensure that we hold a write lock on the inp before calling the function to ensure that multiple threads don't race while trying to invalidate the cache (which previously lead to a page fault). Differential Revision: https://reviews.freebsd.org/D17246 Reviewed by: sbruno, bz, karels Sponsored by: Dell EMC Isilon Approved by: re (gjb) Modified: head/sys/netinet/udp_usrreq.c Modified: head/sys/netinet/udp_usrreq.c ============================================================================== --- head/sys/netinet/udp_usrreq.c Thu Oct 4 21:55:58 2018 (r339184) +++ head/sys/netinet/udp_usrreq.c Thu Oct 4 22:03:58 2018 (r339185) @@ -756,13 +756,7 @@ struct inpcb * udp_notify(struct inpcb *inp, int errno) { - /* - * While udp_ctlinput() always calls udp_notify() with a read lock - * when invoking it directly, in_pcbnotifyall() currently uses write - * locks due to sharing code with TCP. For now, accept either a read - * or a write lock, but a read lock is sufficient. - */ - INP_LOCK_ASSERT(inp); + INP_WLOCK_ASSERT(inp); if ((errno == EHOSTUNREACH || errno == ENETUNREACH || errno == EHOSTDOWN) && inp->inp_route.ro_rt) { RTFREE(inp->inp_route.ro_rt); @@ -808,13 +802,13 @@ udp_common_ctlinput(int cmd, struct sockaddr *sa, void if (ip != NULL) { uh = (struct udphdr *)((caddr_t)ip + (ip->ip_hl << 2)); inp = in_pcblookup(pcbinfo, faddr, uh->uh_dport, - ip->ip_src, uh->uh_sport, INPLOOKUP_RLOCKPCB, NULL); + ip->ip_src, uh->uh_sport, INPLOOKUP_WLOCKPCB, NULL); if (inp != NULL) { - INP_RLOCK_ASSERT(inp); + INP_WLOCK_ASSERT(inp); if (inp->inp_socket != NULL) { udp_notify(inp, inetctlerrmap[cmd]); } - INP_RUNLOCK(inp); + INP_WUNLOCK(inp); } else { inp = in_pcblookup(pcbinfo, faddr, uh->uh_dport, ip->ip_src, uh->uh_sport,
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