From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 16056 invoked by alias); 3 Sep 2009 14:18:32 -0000 Received: (qmail 15970 invoked by uid 48); 3 Sep 2009 14:18:19 -0000 Date: Thu, 03 Sep 2009 14:18:00 -0000 Message-ID: <20090903141819.15969.qmail@sourceware.org> From: "mjw at redhat dot com" To: systemtap@sources.redhat.com In-Reply-To: <20090903122458.10595.mjw@redhat.com> References: <20090903122458.10595.mjw@redhat.com> Reply-To: sourceware-bugzilla@sourceware.org Subject: [Bug uprobes/10595] uprobe return probes causes selinux failures X-Bugzilla-Reason: AssignedTo Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org X-SW-Source: 2009-q3/txt/msg00537.txt.bz2 ------- Additional Comments From mjw at redhat dot com 2009-09-03 14:18 ------- We discussed a bit on irc (and I had a little help interpreting what happened from eparis). Some extra info: - allow_execstack implies allow_execmem. The failure is not really about anything stack related. It comes from setting writable memory executable. - The most likely candidate triggering this issue is in uprobe_setup_ssol_vma: addr = do_mmap_pgoff(NULL, addr, nbytes, PROT_EXEC, MAP_PRIVATE|MAP_ANONYMOUS, 0); As http://people.redhat.com/drepper/selinux-mem.html explains: execmem There are two situations when this error can appear: * The program maps anonymous memory with mmap with PROT_EXEC. Note that because anonymous memory is zero'd out by the system it makes not much sense to not have it writable as well. For user space working around that issue is also explained on that page. That might not be completely trivial in kernel space since it involves mmaping a file twice (we could do that with do_mmap_pgoff where user space uses mmap). ananth suggested we might want to look how vdso/vmap areas get around these restrictions. -- http://sourceware.org/bugzilla/show_bug.cgi?id=10595 ------- You are receiving this mail because: ------- You are the assignee for the bug, or are watching the assignee.