From owner-svn-src-head@freebsd.org Fri Jun 12 18:13:32 2020 Return-Path: Delivered-To: svn-src-head@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 B8BE2341A9F; Fri, 12 Jun 2020 18:13:32 +0000 (UTC) (envelope-from kevans@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 "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 49k83w4Tl0z3bqM; Fri, 12 Jun 2020 18:13:32 +0000 (UTC) (envelope-from kevans@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 950F6D8E5; Fri, 12 Jun 2020 18:13:32 +0000 (UTC) (envelope-from kevans@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id 05CIDWQe056166; Fri, 12 Jun 2020 18:13:32 GMT (envelope-from kevans@FreeBSD.org) Received: (from kevans@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id 05CIDWFX056165; Fri, 12 Jun 2020 18:13:32 GMT (envelope-from kevans@FreeBSD.org) Message-Id: <202006121813.05CIDWFX056165@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: kevans set sender to kevans@FreeBSD.org using -f From: Kyle Evans Date: Fri, 12 Jun 2020 18:13:32 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r362111 - head/lib/libc/gen X-SVN-Group: head X-SVN-Commit-Author: kevans X-SVN-Commit-Paths: head/lib/libc/gen X-SVN-Commit-Revision: 362111 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 12 Jun 2020 18:13:32 -0000 Author: kevans Date: Fri Jun 12 18:13:32 2020 New Revision: 362111 URL: https://svnweb.freebsd.org/changeset/base/362111 Log: posix_spawn: fix for some custom allocator setups libc cannot assume that aligned_alloc and free come from jemalloc, or that any application providing its own malloc and free is actually providing aligned_alloc. Switch back to malloc and just make sure we're passing a properly aligned stack into rfork_thread, as an application perhaps can't reasonably replace just malloc or just free without headaches. This unbreaks ksh93 after r361996, which provides malloc/free but no aligned_alloc. Reported by: freqlabs Diagnosed by: Andrew Gierth X-MFC-With: r361996 Modified: head/lib/libc/gen/posix_spawn.c Modified: head/lib/libc/gen/posix_spawn.c ============================================================================== --- head/lib/libc/gen/posix_spawn.c Fri Jun 12 17:48:12 2020 (r362110) +++ head/lib/libc/gen/posix_spawn.c Fri Jun 12 18:13:32 2020 (r362111) @@ -276,9 +276,19 @@ do_posix_spawn(pid_t *pid, const char *path, stacksz += MAX(3, cnt + 2) * sizeof(char *); stacksz = PSPAWN_STACK_ALIGN(stacksz); } - stack = aligned_alloc(PSPAWN_STACK_ALIGNMENT, stacksz); + + /* + * aligned_alloc is not safe to use here, because we can't guarantee + * that aligned_alloc and free will be provided by the same + * implementation. We've actively hit at least one application that + * will provide its own malloc/free but not aligned_alloc leading to + * a free by the wrong allocator. + */ + stack = malloc(stacksz); if (stack == NULL) return (ENOMEM); + stacksz = (((uintptr_t)stack + stacksz) & ~PSPAWN_STACK_ALIGNBYTES) - + (uintptr_t)stack; #endif psa.path = path; psa.fa = fa;