From owner-freebsd-current@freebsd.org Sat May 18 14:45:58 2019 Return-Path: Delivered-To: freebsd-current@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id C3005158F6DA for ; Sat, 18 May 2019 14:45:58 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from kib.kiev.ua (kib.kiev.ua [IPv6:2001:470:d5e7:1::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 08EF3852C6; Sat, 18 May 2019 14:45:57 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from tom.home (kib@localhost [127.0.0.1]) by kib.kiev.ua (8.15.2/8.15.2) with ESMTPS id x4IEjlcU044993 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Sat, 18 May 2019 17:45:51 +0300 (EEST) (envelope-from kostikbel@gmail.com) DKIM-Filter: OpenDKIM Filter v2.10.3 kib.kiev.ua x4IEjlcU044993 Received: (from kostik@localhost) by tom.home (8.15.2/8.15.2/Submit) id x4IEjl4R044992; Sat, 18 May 2019 17:45:47 +0300 (EEST) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: tom.home: kostik set sender to kostikbel@gmail.com using -f Date: Sat, 18 May 2019 17:45:47 +0300 From: Konstantin Belousov To: Mark Johnston Cc: Rebecca Cran , freebsd-current@freebsd.org Subject: Re: panic booting with if_tap_load="YES" in loader.conf Message-ID: <20190518144547.GE2748@kib.kiev.ua> References: <105ad083-ea95-21a7-35be-de01e32578c4@bluestop.org> <20190518053328.GA7370@raichu> <20190518085546.GY2748@kib.kiev.ua> <20190518142436.GB7370@raichu> <20190518143815.GD2748@kib.kiev.ua> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190518143815.GD2748@kib.kiev.ua> User-Agent: Mutt/1.11.4 (2019-03-13) X-Spam-Status: No, score=-1.0 required=5.0 tests=ALL_TRUSTED,BAYES_00, DKIM_ADSP_CUSTOM_MED,FORGED_GMAIL_RCVD,FREEMAIL_FROM, NML_ADSP_CUSTOM_MED autolearn=no autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on tom.home X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 18 May 2019 14:45:59 -0000 On Sat, May 18, 2019 at 05:38:15PM +0300, Konstantin Belousov wrote: > On Sat, May 18, 2019 at 10:24:36AM -0400, Mark Johnston wrote: > > On Sat, May 18, 2019 at 11:55:46AM +0300, Konstantin Belousov wrote: > > > On Sat, May 18, 2019 at 01:33:28AM -0400, Mark Johnston wrote: > > > > On Fri, May 17, 2019 at 10:18:57PM -0600, Rebecca Cran wrote: > > > > > I just updated from r346856 to r347950 and ran into a new panic, caused > > > > > by having if_tap_load="YES" in /boot/loader.conf - because it's already > > > > > built-in to the kernel: > > > > > > > > I think this patch should fix the panic, but I only compile-tested it. > > > > I considered having the logic live in preload_delete_name() instead, but > > > > the boot-time ucode code must still defer the deletion somewhat. > > > > > > Try this instead. I will revert r347931 after this landed, or could keep > > > it alone. > > > > I have no strong feeling either way. > > > > > diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c > > > index 1cf09dc5cb7..03fe8a5d096 100644 > > > --- a/sys/amd64/amd64/machdep.c > > > +++ b/sys/amd64/amd64/machdep.c > > > @@ -1616,6 +1616,13 @@ hammer_time(u_int64_t modulep, u_int64_t physfree) > > > bzero((void *)thread0.td_kstack, kstack0_sz); > > > physfree += kstack0_sz; > > > > > > + /* > > > + * Initialize enough of thread0 for delayed invalidation to > > > + * work very early. Rely on thread0.td_base_pri > > > + * zero-initialization, it is reset to PVM at proc0_init(). > > > + */ > > > + pmap_thread_init_invl_gen(&thread0); > > > + > > > > I think pmap_thread_init_invl_gen() also needs to initialize > > invl_gen->saved_pri to 0. > It is zero-initialized, same as td_base_pri. The call to > pmap_thread_init_invl_gen() is needed because _INVALID bit must be set, > which is cleared by default. I now think that you mean something else, that invl_gen.saved_pri must be set on each entry to invl_start_u(). Otherwise invl_finish_u() might act on the priority from the previous DI block. diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c index 1cf09dc5cb7..03fe8a5d096 100644 --- a/sys/amd64/amd64/machdep.c +++ b/sys/amd64/amd64/machdep.c @@ -1616,6 +1616,13 @@ hammer_time(u_int64_t modulep, u_int64_t physfree) bzero((void *)thread0.td_kstack, kstack0_sz); physfree += kstack0_sz; + /* + * Initialize enough of thread0 for delayed invalidation to + * work very early. Rely on thread0.td_base_pri + * zero-initialization, it is reset to PVM at proc0_init(). + */ + pmap_thread_init_invl_gen(&thread0); + /* * make gdt memory segments */ diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c index 7997a9f65dc..89ba9da19d8 100644 --- a/sys/amd64/amd64/pmap.c +++ b/sys/amd64/amd64/pmap.c @@ -700,16 +700,17 @@ pmap_delayed_invl_start_u(void) invl_gen = &td->td_md.md_invl_gen; PMAP_ASSERT_NOT_IN_DI(); lock_delay_arg_init(&lda, &di_delay); - thread_lock(td); + invl_gen->saved_pri = 0; pri = td->td_base_pri; - if (pri < PVM) { - invl_gen->saved_pri = 0; - } else { - invl_gen->saved_pri = pri; - sched_prio(td, PVM); + if (pri > PVM) { + thread_lock(td); + pri = td->td_base_pri; + if (pri > PVM) { + invl_gen->saved_pri = pri; + sched_prio(td, PVM); + } + thread_unlock(td); } - thread_unlock(td); - again: PV_STAT(i = 0); for (p = &pmap_invl_gen_head;; p = prev.next) {