From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030526Ab2COOtt (ORCPT ); Thu, 15 Mar 2012 10:49:49 -0400 Received: from mail-pz0-f52.google.com ([209.85.210.52]:55023 "EHLO mail-pz0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030267Ab2COOto (ORCPT ); Thu, 15 Mar 2012 10:49:44 -0400 From: Cong Wang To: linux-kernel@vger.kernel.org Cc: Andrew Morton , Dennis1.Chen@amd.com, Cong Wang , Eric Dumazet , "Paul E. McKenney" , Rusty Russell Subject: [PATCH 2/7] module: take rcu_read_lock_sched for find_symbol Date: Thu, 15 Mar 2012 22:48:56 +0800 Message-Id: <1331822941-19938-2-git-send-email-xiyou.wangcong@gmail.com> X-Mailer: git-send-email 1.7.7.6 In-Reply-To: <1331822941-19938-1-git-send-email-xiyou.wangcong@gmail.com> References: <1331822941-19938-1-git-send-email-xiyou.wangcong@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org find_symbol() iterates module list with list_for_each_entry_rcu() should its caller should hold rcu_read_lock_sched(). This patch changes the module_mutex to rcu_read_lock_sched in resolve_symbol() and adds rcu_read_lock_sched in verify_export_symbols(). Cc: Eric Dumazet Cc: "Paul E. McKenney" Cc: Rusty Russell Signed-off-by: Cong Wang --- kernel/module.c | 7 +++++-- 1 files changed, 5 insertions(+), 2 deletions(-) diff --git a/kernel/module.c b/kernel/module.c index 6f6a3fd..b31b23f 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1174,7 +1174,7 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod, const unsigned long *crc; int err; - mutex_lock(&module_mutex); + rcu_read_lock_sched(); sym = find_symbol(name, &owner, &crc, !(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)), true); if (!sym) @@ -1196,7 +1196,7 @@ getname: /* We must make copy under the lock if we failed to get ref. */ strncpy(ownername, module_name(owner), MODULE_NAME_LEN); unlock: - mutex_unlock(&module_mutex); + rcu_read_unlock_sched(); return sym; } @@ -1844,6 +1844,7 @@ static int verify_export_symbols(struct module *mod) #endif }; + rcu_read_lock_sched(); for (i = 0; i < ARRAY_SIZE(arr); i++) { for (s = arr[i].sym; s < arr[i].sym + arr[i].num; s++) { if (find_symbol(s->name, &owner, NULL, true, false)) { @@ -1851,10 +1852,12 @@ static int verify_export_symbols(struct module *mod) "%s: exports duplicate symbol %s" " (owned by %s)\n", mod->name, s->name, module_name(owner)); + rcu_read_unlock_sched(); return -ENOEXEC; } } } + rcu_read_unlock_sched(); return 0; } -- 1.7.7.6