From owner-svn-src-all@freebsd.org Fri Jun 28 02:14:55 2019 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 5C55C15D53E3; Fri, 28 Jun 2019 02:14:55 +0000 (UTC) (envelope-from dougm@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) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 01AC08458A; Fri, 28 Jun 2019 02:14:55 +0000 (UTC) (envelope-from dougm@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id B8B9D20397; Fri, 28 Jun 2019 02:14:54 +0000 (UTC) (envelope-from dougm@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id x5S2EsnM024676; Fri, 28 Jun 2019 02:14:54 GMT (envelope-from dougm@FreeBSD.org) Received: (from dougm@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id x5S2EsME024675; Fri, 28 Jun 2019 02:14:54 GMT (envelope-from dougm@FreeBSD.org) Message-Id: <201906280214.x5S2EsME024675@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: dougm set sender to dougm@FreeBSD.org using -f From: Doug Moore Date: Fri, 28 Jun 2019 02:14:54 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r349498 - head/sys/vm X-SVN-Group: head X-SVN-Commit-Author: dougm X-SVN-Commit-Paths: head/sys/vm X-SVN-Commit-Revision: 349498 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 01AC08458A X-Spamd-Bar: -- Authentication-Results: mx1.freebsd.org X-Spamd-Result: default: False [-2.96 / 15.00]; local_wl_from(0.00)[FreeBSD.org]; NEURAL_HAM_MEDIUM(-1.00)[-0.999,0]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; NEURAL_HAM_SHORT(-0.96)[-0.960,0]; ASN(0.00)[asn:11403, ipnet:2610:1c1:1::/48, country:US] X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 28 Jun 2019 02:14:55 -0000 Author: dougm Date: Fri Jun 28 02:14:54 2019 New Revision: 349498 URL: https://svnweb.freebsd.org/changeset/base/349498 Log: If vm_map_protect fails with KERN_RESOURCE_SHORTAGE, be sure to simplify modified entries before returning. Reviewed by: alc, markj (earlier version), kib (earlier version) Approved by: kib, markj (mentors, implicit) Differential Revision: https://reviews.freebsd.org/D20753 Modified: head/sys/vm/vm_map.c Modified: head/sys/vm/vm_map.c ============================================================================== --- head/sys/vm/vm_map.c Fri Jun 28 01:57:59 2019 (r349497) +++ head/sys/vm/vm_map.c Fri Jun 28 02:14:54 2019 (r349498) @@ -2454,6 +2454,7 @@ vm_map_protect(vm_map_t map, vm_offset_t start, vm_off vm_object_t obj; struct ucred *cred; vm_prot_t old_prot; + int rv; if (start == end) return (KERN_SUCCESS); @@ -2508,10 +2509,13 @@ again: } /* - * Do an accounting pass for private read-only mappings that - * now will do cow due to allowed write (e.g. debugger sets - * breakpoint on text segment) + * Before changing the protections, try to reserve swap space for any + * private (i.e., copy-on-write) mappings that are transitioning from + * read-only to read/write access. If a reservation fails, break out + * of this loop early and let the next loop simplify the entries, since + * some may now be mergeable. */ + rv = KERN_SUCCESS; vm_map_clip_start(map, entry, start); for (current = entry; current->start < end; current = current->next) { @@ -2529,8 +2533,9 @@ again: if (obj == NULL || (current->eflags & MAP_ENTRY_NEEDS_COPY)) { if (!swap_reserve(current->end - current->start)) { - vm_map_unlock(map); - return (KERN_RESOURCE_SHORTAGE); + rv = KERN_RESOURCE_SHORTAGE; + end = current->end; + break; } crhold(cred); current->cred = cred; @@ -2553,8 +2558,9 @@ again: obj, current)); if (!swap_reserve(ptoa(obj->size))) { VM_OBJECT_WUNLOCK(obj); - vm_map_unlock(map); - return (KERN_RESOURCE_SHORTAGE); + rv = KERN_RESOURCE_SHORTAGE; + end = current->end; + break; } crhold(cred); @@ -2564,11 +2570,14 @@ again: } /* - * Go back and fix up protections. [Note that clipping is not - * necessary the second time.] + * If enough swap space was available, go back and fix up protections. + * Otherwise, just simplify entries, since some may have been modified. + * [Note that clipping is not necessary the second time.] */ - for (current = entry; current->start < end; current = current->next) { - if ((current->eflags & MAP_ENTRY_GUARD) != 0) + for (current = entry; current->start < end; + vm_map_simplify_entry(map, current), current = current->next) { + if (rv != KERN_SUCCESS || + (current->eflags & MAP_ENTRY_GUARD) != 0) continue; old_prot = current->protection; @@ -2603,10 +2612,9 @@ again: current->protection & MASK(current)); #undef MASK } - vm_map_simplify_entry(map, current); } vm_map_unlock(map); - return (KERN_SUCCESS); + return (rv); } /*