From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932678Ab2IMATR (ORCPT ); Wed, 12 Sep 2012 20:19:17 -0400 Received: from mail-oa0-f46.google.com ([209.85.219.46]:50843 "EHLO mail-oa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756693Ab2ILXgr (ORCPT ); Wed, 12 Sep 2012 19:36:47 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg KH , Oleg Nesterov , Srikar Dronamraju , Anton Arapov , William Cohen , Linus Torvalds , Ingo Molnar Subject: [ 105/108] uprobes: Fix mmap_region()s mm->mm_rb corruption if uprobe_mmap() fails Date: Wed, 12 Sep 2012 16:29:43 -0700 Message-Id: <20120912232501.510809318@linuxfoundation.org> X-Mailer: git-send-email 1.7.10.1.362.g242cab3 In-Reply-To: <20120912232450.500619493@linuxfoundation.org> References: <20120912232816.GA1655@kroah.com> <20120912232450.500619493@linuxfoundation.org> User-Agent: quilt/0.60-2.1.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Greg KH 3.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Oleg Nesterov commit c7a3a88c938fbe3d70c2278e082b80eb830d1c58 upstream. This patch fixes: https://bugzilla.redhat.com/show_bug.cgi?id=843640 If mmap_region()->uprobe_mmap() fails, unmap_and_free_vma path does unmap_region() but does not remove the soon-to-be-freed vma from rb tree. Actually there are more problems but this is how William noticed this bug. Perhaps we could do do_munmap() + return in this case, but in fact it is simply wrong to abort if uprobe_mmap() fails. Until at least we move the !UPROBE_COPY_INSN code from install_breakpoint() to uprobe_register(). For example, uprobe_mmap()->install_breakpoint() can fail if the probed insn is not supported (remember, uprobe_register() succeeds if nobody mmaps inode/offset), mmap() should not fail in this case. dup_mmap()->uprobe_mmap() is wrong too by the same reason, fork() can race with uprobe_register() and fail for no reason if it wins the race and does install_breakpoint() first. And, if nothing else, both mmap_region() and dup_mmap() return success if uprobe_mmap() fails. Change them to ignore the error code from uprobe_mmap(). Reported-and-tested-by: William Cohen Signed-off-by: Oleg Nesterov Acked-by: Srikar Dronamraju Cc: Anton Arapov Cc: William Cohen Cc: Linus Torvalds Link: http://lkml.kernel.org/r/20120819171042.GB26957@redhat.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- kernel/fork.c | 4 ++-- mm/mmap.c | 5 ++--- 2 files changed, 4 insertions(+), 5 deletions(-) --- a/kernel/fork.c +++ b/kernel/fork.c @@ -459,8 +459,8 @@ static int dup_mmap(struct mm_struct *mm if (retval) goto out; - if (file && uprobe_mmap(tmp)) - goto out; + if (file) + uprobe_mmap(tmp); } /* a new mm has just been created */ arch_dup_mmap(oldmm, mm); --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1355,9 +1355,8 @@ out: } else if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK)) make_pages_present(addr, addr + len); - if (file && uprobe_mmap(vma)) - /* matching probes but cannot insert */ - goto unmap_and_free_vma; + if (file) + uprobe_mmap(vma); return addr;