From owner-dev-commits-src-all@freebsd.org Wed Sep 29 20:27:39 2021 Return-Path: Delivered-To: dev-commits-src-all@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 93FBF67B346; Wed, 29 Sep 2021 20:27:39 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4HKSbv2Vk9z4psF; Wed, 29 Sep 2021 20:27:39 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 0F30F1EE06; Wed, 29 Sep 2021 20:27:39 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.16.1/8.16.1) with ESMTP id 18TKRck5038652; Wed, 29 Sep 2021 20:27:38 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 18TKRc5u038651; Wed, 29 Sep 2021 20:27:38 GMT (envelope-from git) Date: Wed, 29 Sep 2021 20:27:38 GMT Message-Id: <202109292027.18TKRc5u038651@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Vladimir Kondratyev Subject: git: 62ff0566c930 - main - LinuxKPI: Allow cdev_pager prefault handler to steal pages MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: wulf X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: 62ff0566c93056e00b3c9c3f8d2ac1e7d8e0c098 Auto-Submitted: auto-generated X-BeenThere: dev-commits-src-all@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Commit messages for all branches of the src repository List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 29 Sep 2021 20:27:39 -0000 The branch main has been updated by wulf: URL: https://cgit.FreeBSD.org/src/commit/?id=62ff0566c93056e00b3c9c3f8d2ac1e7d8e0c098 commit 62ff0566c93056e00b3c9c3f8d2ac1e7d8e0c098 Author: Vladimir Kondratyev AuthorDate: 2021-09-29 20:14:05 +0000 Commit: Vladimir Kondratyev CommitDate: 2021-09-29 20:14:05 +0000 LinuxKPI: Allow cdev_pager prefault handler to steal pages from other vm_objects. This workarounds "Page already inserted" panic in vm_page_insert routine triggered on attempt to mmap file created with shmem_file_setup call. After introduction of "GTT mmap interface v4" a.k.a. MMAP_OFFSET, vm_objects allocated by these calls may try to own intersected sets of pages that leads to the assertion. Reviewed by: kib MFC after: 2 weeks Differential revision: https://reviews.freebsd.org/D32090 --- sys/compat/linuxkpi/common/src/linux_page.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/sys/compat/linuxkpi/common/src/linux_page.c b/sys/compat/linuxkpi/common/src/linux_page.c index cbe6d2530b91..c7191fef3429 100644 --- a/sys/compat/linuxkpi/common/src/linux_page.c +++ b/sys/compat/linuxkpi/common/src/linux_page.c @@ -281,6 +281,7 @@ lkpi_vmf_insert_pfn_prot_locked(struct vm_area_struct *vma, unsigned long addr, unsigned long pfn, pgprot_t prot) { vm_object_t vm_obj = vma->vm_obj; + vm_object_t tmp_obj; vm_page_t page; vm_pindex_t pindex; @@ -296,6 +297,32 @@ retry: page = PHYS_TO_VM_PAGE(IDX_TO_OFF(pfn)); if (!vm_page_busy_acquire(page, VM_ALLOC_WAITFAIL)) goto retry; + if (page->object != NULL) { + tmp_obj = page->object; + vm_page_xunbusy(page); + VM_OBJECT_WUNLOCK(vm_obj); + VM_OBJECT_WLOCK(tmp_obj); + if (page->object == tmp_obj && + vm_page_busy_acquire(page, VM_ALLOC_WAITFAIL)) { + KASSERT(page->object == tmp_obj, + ("page has changed identity")); + KASSERT((page->oflags & VPO_UNMANAGED) == 0, + ("page does not belong to shmem")); + vm_pager_page_unswapped(page); + if (pmap_page_is_mapped(page)) { + vm_page_xunbusy(page); + VM_OBJECT_WUNLOCK(tmp_obj); + printf("%s: page rename failed: page " + "is mapped\n", __func__); + VM_OBJECT_WLOCK(vm_obj); + return (VM_FAULT_NOPAGE); + } + vm_page_remove(page); + } + VM_OBJECT_WUNLOCK(tmp_obj); + VM_OBJECT_WLOCK(vm_obj); + goto retry; + } if (vm_page_insert(page, vm_obj, pindex)) { vm_page_xunbusy(page); return (VM_FAULT_OOM);