Patchwork caif: Fix race when conditionally taking rtnl lock

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Submitter sjur.brandeland@stericsson.com
Date June 1, 2011, 10:55 a.m.
Message ID <1306925737-1782-1-git-send-email-sjur.brandeland@stericsson.com>
Download mbox | patch
Permalink /patch/98166/
State Accepted
Delegated to: David Miller
Headers show

Comments

sjur.brandeland@stericsson.com - June 1, 2011, 10:55 a.m.
Take the RTNL lock unconditionally when calling dev_close.
Taking the lock conditionally may cause race conditions.

Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
---
 net/caif/chnl_net.c |    9 +++------
 1 files changed, 3 insertions(+), 6 deletions(-)
David Miller - June 2, 2011, 4:14 a.m.
From: Sjur Brændeland <sjur.brandeland@stericsson.com>
Date: Wed,  1 Jun 2011 12:55:37 +0200

> Take the RTNL lock unconditionally when calling dev_close.
> Taking the lock conditionally may cause race conditions.
> 
> Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>

Applied, thanks.
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Patch

diff --git a/net/caif/chnl_net.c b/net/caif/chnl_net.c
index 649ebac..adbb424 100644
--- a/net/caif/chnl_net.c
+++ b/net/caif/chnl_net.c
@@ -139,17 +139,14 @@  static void close_work(struct work_struct *work)
 	struct chnl_net *dev = NULL;
 	struct list_head *list_node;
 	struct list_head *_tmp;
-	/* May be called with or without RTNL lock held */
-	int islocked = rtnl_is_locked();
-	if (!islocked)
-		rtnl_lock();
+
+	rtnl_lock();
 	list_for_each_safe(list_node, _tmp, &chnl_net_list) {
 		dev = list_entry(list_node, struct chnl_net, list_field);
 		if (dev->state == CAIF_SHUTDOWN)
 			dev_close(dev->netdev);
 	}
-	if (!islocked)
-		rtnl_unlock();
+	rtnl_unlock();
 }
 static DECLARE_WORK(close_worker, close_work);