[PATCH 4/7] module: take rcu_read_lock_sched in module_kallsyms_on_each_symbol()

From: Cong Wang <xiyou.wangcong@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Dennis1.Chen@amd.com, Cong Wang <xiyou.wangcong@gmail.com>,
	Eric Dumazet <eric.dumazet@gmail.com>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Rusty Russell <rusty@rustcorp.com.au>
Subject: [PATCH 4/7] module: take rcu_read_lock_sched in module_kallsyms_on_each_symbol()
Date: Thu, 15 Mar 2012 22:48:58 +0800	[thread overview]
Message-ID: <1331822941-19938-4-git-send-email-xiyou.wangcong@gmail.com> (raw)
In-Reply-To: <1331822941-19938-1-git-send-email-xiyou.wangcong@gmail.com>

module_kallsyms_on_each_symbol() should iterate the module list
with list_for_each_entry_rcu() after holding rcu_read_lock_sched().

Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
---
 kernel/module.c |    8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index f210d74..73e1f95 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3271,14 +3271,18 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 	unsigned int i;
 	int ret;
 
-	list_for_each_entry(mod, &modules, list) {
+	rcu_read_lock_sched();
+	list_for_each_entry_rcu(mod, &modules, list) {
 		for (i = 0; i < mod->num_symtab; i++) {
 			ret = fn(data, mod->strtab + mod->symtab[i].st_name,
 				 mod, mod->symtab[i].st_value);
-			if (ret != 0)
+			if (ret != 0) {
+				rcu_read_unlock_sched();
 				return ret;
+			}
 		}
 	}
+	rcu_read_unlock_sched();
 	return 0;
 }
 #endif /* CONFIG_KALLSYMS */
-- 
1.7.7.6

