From owner-dev-commits-src-main@freebsd.org Thu Mar 11 15:37:54 2021 Return-Path: Delivered-To: dev-commits-src-main@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 C19CE57954E; Thu, 11 Mar 2021 15:37:54 +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 4DxCkp59f1z3DCS; Thu, 11 Mar 2021 15:37:54 +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 A47A827492; Thu, 11 Mar 2021 15:37:54 +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 12BFbsiA093086; Thu, 11 Mar 2021 15:37:54 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 12BFbsES093085; Thu, 11 Mar 2021 15:37:54 GMT (envelope-from git) Date: Thu, 11 Mar 2021 15:37:54 GMT Message-Id: <202103111537.12BFbsES093085@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: 968079f253c1 - main - vm_reserv: Fix list locking in vm_reserv_reclaim_contig() 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: 968079f253c11433d47bece4b41b46fcbf985903 Auto-Submitted: auto-generated X-BeenThere: dev-commits-src-main@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Commit messages for the main branch of the src repository List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 11 Mar 2021 15:37:54 -0000 The branch main has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=968079f253c11433d47bece4b41b46fcbf985903 commit 968079f253c11433d47bece4b41b46fcbf985903 Author: Mark Johnston AuthorDate: 2021-03-11 15:34:28 +0000 Commit: Mark Johnston CommitDate: 2021-03-11 15:35:35 +0000 vm_reserv: Fix list locking in vm_reserv_reclaim_contig() The per-domain partpop queue is locked by the combination of the per-domain lock and individual reservation mutexes. vm_reserv_reclaim_contig() scans the queue looking for partially populated reservations that can be reclaimed in order to satisfy the caller's allocation. During the scan, we drop the per-domain lock. At this point, the rvn pointer may be invalidated. Take care to load rvn after re-acquiring the per-domain lock. While here, simplify the condition used to check whether a reservation was dequeued while the per-domain lock was dropped. Reviewed by: alc, kib Reported by: gallatin MFC after: 3 days Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D29203 --- sys/vm/vm_reserv.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/sys/vm/vm_reserv.c b/sys/vm/vm_reserv.c index e7f542a66fdb..a9602c3977df 100644 --- a/sys/vm/vm_reserv.c +++ b/sys/vm/vm_reserv.c @@ -1344,8 +1344,8 @@ vm_reserv_reclaim_contig(int domain, u_long npages, vm_paddr_t low, TAILQ_INSERT_AFTER(queue, rv, marker, partpopq); vm_reserv_domain_unlock(domain); vm_reserv_lock(rv); - if (!rv->inpartpopq || - TAILQ_NEXT(rv, partpopq) != marker) { + if (TAILQ_PREV(marker, vm_reserv_queue, partpopq) != + rv) { vm_reserv_unlock(rv); vm_reserv_domain_lock(domain); rvn = TAILQ_NEXT(marker, partpopq); @@ -1363,8 +1363,9 @@ vm_reserv_reclaim_contig(int domain, u_long npages, vm_paddr_t low, vm_reserv_unlock(rv); return (true); } - vm_reserv_unlock(rv); vm_reserv_domain_lock(domain); + rvn = TAILQ_NEXT(rv, partpopq); + vm_reserv_unlock(rv); } vm_reserv_domain_unlock(domain); vm_reserv_domain_scan_unlock(domain);