From nobody Wed Jun 15 15:39:24 2022 X-Original-To: dev-commits-src-all@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id E3BFD855074; Wed, 15 Jun 2022 15:39:24 +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 4LNTxm5xcLz4lxB; Wed, 15 Jun 2022 15:39:24 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1655307564; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=gfRt6aYmLO2PTCtdmKXuY+KFCJ/ixgAFABI2KU9kWDQ=; b=U1BAYpG6BTJChodV++HcVmBVInhXqPT2WW+PxIG8XqQg5GtvWoP2kOdIhbN1jnfc064jVg 4tdCydw8qUNzEfhPjN1r39z4tjsuoyHBjyhMyKenKlPPrkkcPjMyxKvQfsSxZLeJZ5+FDl cchW7EvAQMA5Whv+8wZkPzqEmwCnMuYmQjnzMlvKVYKbi0hH7q3jxWwDMZgRYvuUDMoP/2 /2S+0B1bEKAc76LuLo/xkW7w/V/pQ2eg+TGRghpReI8WkNShd9zVS8HVETOi819GMOZZSu wQfVDceeVXHZq+c1tfeTnDIApM5sRi0KvoS4TXW9o1o904w9BsEXY5pqMm41Qg== 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 ABD5921398; Wed, 15 Jun 2022 15:39:24 +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 25FFdOcl085369; Wed, 15 Jun 2022 15:39:24 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 25FFdOSD085368; Wed, 15 Jun 2022 15:39:24 GMT (envelope-from git) Date: Wed, 15 Jun 2022 15:39:24 GMT Message-Id: <202206151539.25FFdOSD085368@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Mark Johnston Subject: git: c6d092b5107d - main - pmap: Keep PTI page table pages busy List-Id: Commit messages for all branches of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-all List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-dev-commits-src-all@freebsd.org X-BeenThere: dev-commits-src-all@freebsd.org MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: markj X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: c6d092b5107d1a3acefa977828b8130c0505fe7b Auto-Submitted: auto-generated ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1655307564; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=gfRt6aYmLO2PTCtdmKXuY+KFCJ/ixgAFABI2KU9kWDQ=; b=kuWP+GCzIvnreABsqBTvYOg+yl2fg9PMOOcA23CU6RRVn0kBiUpVQAq9yDqrYOcSJaIGcH IJTnNCyN7bkoQP4ArMo5ujIk/69Bf6EIkZTUNOBtSUK666d3yNuE6MNxOJaCzpf+OCulvt zdKTDkerGplLtsbWY8ei3oFU/D22Rluurcn6BsqOnrD01dJZRoIZqdjLWXfXDgweQ1jrN7 /21egBtNABClZCKuNMOWPw2dCPoMVfP/JspFG0GunA5D54j464bGwsAGkNM72SgILQcUo+ TadqmvqGp2WjXOJ3gW5/0JX3wWoch6mdCNf+4sg15Q99KjtthUwKWo3uj98Fhg== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1655307564; a=rsa-sha256; cv=none; b=vWM2nZQiAjKai9jqRo5Kq25n/j2pI/8jhY2OjeswArEtzhlbFGDX6qwvLc7batOUyyIjXH YCBm2s1SVuH4Am0rGBIxBNXjJU4I80O4bhookzdRyDGwBA35qPDnGrMlrWhWkoaorXnzzw lkF1tkWG2d3N7E7+ERWnP8KDJv4B2et2GRypX+Jp5Ac+DATwnpwSyVwhbsrY6cR06nJWOV miARszsxAl7UZXgRlpEd/NIs12tpdAeYMtlT2ya6masbNh+anlbYAjfOx3If64RxpsiKY6 GH/vk1xbineql8jEVvFtIsWMR01v6ZDc1qMWntPhd+GWzDMqxeCsJeK7ImcZ0w== ARC-Authentication-Results: i=1; mx1.freebsd.org; none X-ThisMailContainsUnwantedMimeParts: N The branch main has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=c6d092b5107d1a3acefa977828b8130c0505fe7b commit c6d092b5107d1a3acefa977828b8130c0505fe7b Author: Mark Johnston AuthorDate: 2022-06-15 14:19:01 +0000 Commit: Mark Johnston CommitDate: 2022-06-15 15:38:04 +0000 pmap: Keep PTI page table pages busy PTI page table pages are allocated from a VM object, so must be exclusively busied when they are freed, e.g., when a thread loses a race in pmap_pti_pde(). Simply keep PTPs busy at all times, as was done for some other kernel allocators in commit e9ceb9dd110e04fc19729b4e9fb1c8bfbb8398a3. Also remove some redundant assertions on "ref_count": vm_page_unwire_noq() already asserts that the page's reference count is greater than zero. Reported by: syzkaller Reviewed by: kib MFC after: 2 weeks Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D35466 --- sys/amd64/amd64/pmap.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c index 5350bff2fef4..a4e796becc73 100644 --- a/sys/amd64/amd64/pmap.c +++ b/sys/amd64/amd64/pmap.c @@ -10867,18 +10867,16 @@ pmap_pti_alloc_page(void) vm_page_t m; VM_OBJECT_ASSERT_WLOCKED(pti_obj); - m = vm_page_grab(pti_obj, pti_pg_idx++, VM_ALLOC_NOBUSY | - VM_ALLOC_WIRED | VM_ALLOC_ZERO); + m = vm_page_grab(pti_obj, pti_pg_idx++, VM_ALLOC_WIRED | VM_ALLOC_ZERO); return (m); } static bool pmap_pti_free_page(vm_page_t m) { - - KASSERT(m->ref_count > 0, ("page %p not referenced", m)); if (!vm_page_unwire_noq(m)) return (false); + vm_page_xbusy_claim(m); vm_page_free_zero(m); return (true); } @@ -10984,7 +10982,6 @@ pmap_pti_unwire_pde(void *pde, bool only_ref) VM_OBJECT_ASSERT_WLOCKED(pti_obj); m = PHYS_TO_VM_PAGE(DMAP_TO_PHYS((uintptr_t)pde)); - MPASS(m->ref_count > 0); MPASS(only_ref || m->ref_count > 1); pmap_pti_free_page(m); } @@ -10997,7 +10994,6 @@ pmap_pti_unwire_pte(void *pte, vm_offset_t va) VM_OBJECT_ASSERT_WLOCKED(pti_obj); m = PHYS_TO_VM_PAGE(DMAP_TO_PHYS((uintptr_t)pte)); - MPASS(m->ref_count > 0); if (pmap_pti_free_page(m)) { pde = pmap_pti_pde(va); MPASS((*pde & (X86_PG_PS | X86_PG_V)) == X86_PG_V);