From owner-freebsd-stable@FreeBSD.ORG Sat Oct 4 08:29:48 2014 Return-Path: Delivered-To: stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id C911FF60; Sat, 4 Oct 2014 08:29:48 +0000 (UTC) Received: from kib.kiev.ua (kib.kiev.ua [IPv6:2001:470:d5e7:1::1]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 546F92D7; Sat, 4 Oct 2014 08:29:48 +0000 (UTC) Received: from tom.home (kostik@localhost [127.0.0.1]) by kib.kiev.ua (8.14.9/8.14.9) with ESMTP id s948Thsk034440 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Sat, 4 Oct 2014 11:29:43 +0300 (EEST) (envelope-from kostikbel@gmail.com) DKIM-Filter: OpenDKIM Filter v2.9.2 kib.kiev.ua s948Thsk034440 Received: (from kostik@localhost) by tom.home (8.14.9/8.14.9/Submit) id s948ThYo034439; Sat, 4 Oct 2014 11:29:43 +0300 (EEST) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: tom.home: kostik set sender to kostikbel@gmail.com using -f Date: Sat, 4 Oct 2014 11:29:43 +0300 From: Konstantin Belousov To: Kohji Okuno Subject: Re: About pmap_mapdev() & pmap_unmapdev() Message-ID: <20141004082943.GN26076@kib.kiev.ua> References: <20141003.172533.863334695746935674.okuno.kohji@jp.panasonic.com> <20141003215830.GK26076@kib.kiev.ua> <20141004.170036.336251378907610162.okuno.kohji@jp.panasonic.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20141004.170036.336251378907610162.okuno.kohji@jp.panasonic.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-Spam-Status: No, score=-2.0 required=5.0 tests=ALL_TRUSTED,BAYES_00, DKIM_ADSP_CUSTOM_MED,FREEMAIL_FROM,NML_ADSP_CUSTOM_MED autolearn=no autolearn_force=no version=3.4.0 X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on tom.home Cc: stable@freebsd.org, freebsd-current@freebsd.org X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 04 Oct 2014 08:29:48 -0000 On Sat, Oct 04, 2014 at 05:00:36PM +0900, Kohji Okuno wrote: > Hi, Konstantin, > > Thank you for your comment. > And, your change is better than mine. At the end of the mail is commit candidate. I did not even compiled this. Can you test and report back, please ? > > > Do you mean that this panic is related to missed pmap_remove() ? > > I doubt it, since pmap_mapdev() does not establish managed mappings. > > Yes, pmap_mapdev() does not establish managed mappings. But, if > kernel_pmap.pm_stats.resident_count is zero, then any managed pages > (for example pipe_map, exec_map, or etc.) are not able to change > unmanaged status, because pmap_remove() returns without calling > pmap_remove_pte(). > > In this result, I encounterd the panic. Could you refer the following? Yes, kmem_back() indeed uses managed mapping. Index: amd64/amd64/pmap.c =================================================================== --- amd64/amd64/pmap.c (revision 272506) +++ amd64/amd64/pmap.c (working copy) @@ -5040,6 +5040,9 @@ pmap_mapdev_attr(vm_paddr_t pa, vm_size_t size, in pa = trunc_page(pa); for (tmpsize = 0; tmpsize < size; tmpsize += PAGE_SIZE) pmap_kenter_attr(va + tmpsize, pa + tmpsize, mode); + PMAP_LOCK(kernel_pmap); + kernel_pmap.pm_stats.resident_count += OFF_TO_IDX(size); + PMAP_UNLOCK(kernel_pmap); pmap_invalidate_range(kernel_pmap, va, va + tmpsize); pmap_invalidate_cache_range(va, va + tmpsize); return ((void *)(va + offset)); Index: i386/i386/pmap.c =================================================================== --- i386/i386/pmap.c (revision 272506) +++ i386/i386/pmap.c (working copy) @@ -5066,10 +5066,14 @@ pmap_mapdev_attr(vm_paddr_t pa, vm_size_t size, in size = roundup(offset + size, PAGE_SIZE); pa = pa & PG_FRAME; - if (pa < KERNLOAD && pa + size <= KERNLOAD) + if (pa < KERNLOAD && pa + size <= KERNLOAD) { va = KERNBASE + pa; - else + } else { va = kmem_alloc_nofault(kernel_map, size); + PMAP_LOCK(kernel_pmap); + kernel_pmap.pm_stats.resident_count += OFF_TO_IDX(size); + PMAP_UNLOCK(kernel_pmap); + } if (!va) panic("pmap_mapdev: Couldn't alloc kernel virtual memory");