From nobody Wed Jun 29 14:40:55 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 0FCF986D932; Wed, 29 Jun 2022 14:40:56 +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 4LY3zq4KPGz4j2c; Wed, 29 Jun 2022 14:40:55 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1656513655; 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=hyDmAsPaRYg+Otm6S3HBCilWBFfVlFoBUkFyKyK5VSA=; b=nLfEAWtOgGyTdtRg2l55GF+j1VM3sv+ZvS/ffGRWLvJ/1LBRp6vMubceB4/f3MPU/F4nA6 zcEgCWnWOrb/q4iHpYLW4ECFq9p/oCx3GyftrvnFXavhMTYFedje2TPGRTd6sD4ZwtfZUQ ikHeDiSh5izH3mWFFIxOlOhFBb7SxG68hYRYDEr5sHlv9Z2lfsPPRJrZ8SwQkCQxbDqCSJ UJ86MWP5eQy9jxJVKlvaMKkmjCUsLHWuFX1xhemNTP/uZ0lrgppyufiHoZbGoAq/wKiFlL LiJ2om97BmT6SsTxBSX8JcDNztAVQaT7AK4ktf2VS9KBArB2S6Fbd3Gv+zDFQw== 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 6750E13B03; Wed, 29 Jun 2022 14:40:55 +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 25TEet6N031711; Wed, 29 Jun 2022 14:40:55 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 25TEetRS031710; Wed, 29 Jun 2022 14:40:55 GMT (envelope-from git) Date: Wed, 29 Jun 2022 14:40:55 GMT Message-Id: <202206291440.25TEetRS031710@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Mark Johnston Subject: git: cc81b8661d50 - stable/13 - vm_fault: Fix a racy copy of page valid bits 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/stable/13 X-Git-Reftype: branch X-Git-Commit: cc81b8661d5085a470c0f1821fa68bee2d8fa39c Auto-Submitted: auto-generated ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1656513655; 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=hyDmAsPaRYg+Otm6S3HBCilWBFfVlFoBUkFyKyK5VSA=; b=pC3/l0Y1cJyzIHlp7duehaypcjCU5w1GsIsUTK/DBESuM2t31aVKAmhHfc8971CNfyUPPX E5Gt6kXgVEXNEHPttEmxgLgViCCiLhwYxsLZRfXMKLhQWmN9YAkS4Fjj/2OTPfzC8rQjYU Rr0rDNCuS5Bx1VX0PjnnblLWYiy709kcZsrqw9f/gRSjmfepfw7+MQFwaqDKCzkl9B77+x i9IgG2y/ucJRm+VgiQ7qlERD5aWDtRXP40B1E2DDR6IIxpD9V2BdG96mQBzLAtJG90B+Nj 4/D+fgVMtliMQhbY4z5rklofVPJCVGE0/tEihXurnODLW4uNDhAt+Qwr96ErIw== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1656513655; a=rsa-sha256; cv=none; b=PcoUhdkMdLOo88/vT8I/t+qJCFkUeU3TUvsjkfKgFjMObK3zPYSgJJ8sqK5ygATWOP/zHA NvWKXwz+rXn7BDal4S1ycM97gXywFn2ByxU1kM4/D92nYkJC4yn3uLLIChZA6K6vQLhiyP T+vrixmpEyRluOMuHvvRp6z1P/rQWul2XoiJtKubm8QlsgOd7soLICmJ2ChG9hBJBby4xV 6XXzkyvyBsHZ514k4MBEqP93b1jwbfTqoYk9R8QxF0fiF2yzjLBJkRTM2k4P2HkETWYuHs PcTH3jpGkSbNioN7tU80oShg6Qfbf4npyv7/r981DGGtEtcS3O0ZtcvBL0risQ== ARC-Authentication-Results: i=1; mx1.freebsd.org; none X-ThisMailContainsUnwantedMimeParts: N The branch stable/13 has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=cc81b8661d5085a470c0f1821fa68bee2d8fa39c commit cc81b8661d5085a470c0f1821fa68bee2d8fa39c Author: Mark Johnston AuthorDate: 2022-06-14 20:36:54 +0000 Commit: Mark Johnston CommitDate: 2022-06-29 14:12:34 +0000 vm_fault: Fix a racy copy of page valid bits We do not hold the object lock or a page busy lock when copying src_m's validity state. Prior to commit 45d72c7d7fca we marked dst_m as fully valid. Use the source object's read lock to ensure that valid bits are not concurrently cleared. Reviewed by: alc, kib Fixes: 45d72c7d7fca ("vm_fault_copy_entry: accept invalid source pages.") Sponsored by: The FreeBSD Foundation (cherry picked from commit d0443e2b9832f01319bcaaece8102d998bf81f01) --- sys/vm/vm_fault.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/sys/vm/vm_fault.c b/sys/vm/vm_fault.c index 0e155ed1f39d..8981be84b5d2 100644 --- a/sys/vm/vm_fault.c +++ b/sys/vm/vm_fault.c @@ -2100,8 +2100,15 @@ again: goto again; } pmap_copy_page(src_m, dst_m); - VM_OBJECT_RUNLOCK(object); + + /* + * The object lock does not guarantee that "src_m" will + * transition from invalid to valid, but it does ensure + * that "src_m" will not transition from valid to + * invalid. + */ dst_m->dirty = dst_m->valid = src_m->valid; + VM_OBJECT_RUNLOCK(object); } else { dst_m = src_m; if (vm_page_busy_acquire(dst_m, VM_ALLOC_WAITFAIL) == 0)