Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933017AbbGSTSg (ORCPT ); Sun, 19 Jul 2015 15:18:36 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:38788 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932503AbbGSTSc (ORCPT ); Sun, 19 Jul 2015 15:18:32 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Miroslav Benes , Josh Poimboeuf , Jiri Kosina Subject: [PATCH 4.0 39/58] livepatch: add module locking around kallsyms calls Date: Sun, 19 Jul 2015 12:11:17 -0700 Message-Id: <20150719190812.577250607@linuxfoundation.org> X-Mailer: git-send-email 2.4.6 In-Reply-To: <20150719190811.308546345@linuxfoundation.org> References: <20150719190811.308546345@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2106 Lines: 70 4.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Miroslav Benes commit 9a1bd63cdae4b623494c4ebaf723a91c35ec49fb upstream. The list of loaded modules is walked through in module_kallsyms_on_each_symbol (called by kallsyms_on_each_symbol). The module_mutex lock should be acquired to prevent potential corruptions in the list. This was uncovered with new lockdep asserts in module code introduced by the commit 0be964be0d45 ("module: Sanitize RCU usage and locking") in recent next- trees. Signed-off-by: Miroslav Benes Acked-by: Josh Poimboeuf Signed-off-by: Jiri Kosina Signed-off-by: Greg Kroah-Hartman --- kernel/livepatch/core.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -179,7 +179,9 @@ static int klp_find_object_symbol(const .count = 0 }; + mutex_lock(&module_mutex); kallsyms_on_each_symbol(klp_find_callback, &args); + mutex_unlock(&module_mutex); if (args.count == 0) pr_err("symbol '%s' not found in symbol table\n", name); @@ -219,13 +221,19 @@ static int klp_verify_vmlinux_symbol(con .name = name, .addr = addr, }; + int ret; - if (kallsyms_on_each_symbol(klp_verify_callback, &args)) - return 0; + mutex_lock(&module_mutex); + ret = kallsyms_on_each_symbol(klp_verify_callback, &args); + mutex_unlock(&module_mutex); + + if (!ret) { + pr_err("symbol '%s' not found at specified address 0x%016lx, kernel mismatch?\n", + name, addr); + return -EINVAL; + } - pr_err("symbol '%s' not found at specified address 0x%016lx, kernel mismatch?\n", - name, addr); - return -EINVAL; + return 0; } static int klp_find_verify_func_addr(struct klp_object *obj, -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/