linux-kernel - [PATCH 5.15 079/244] plip: avoid rcu debug splat

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Message-Id: <20220823080101.686057284@linuxfoundation.org>
Date:   Tue, 23 Aug 2022 10:23:58 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, kernel test robot <oliver.sang@...el.com>,
        Florian Westphal <fw@...len.de>,
        Jakub Kicinski <kuba@...nel.org>
Subject: [PATCH 5.15 079/244] plip: avoid rcu debug splat

From: Florian Westphal <fw@...len.de>

commit bc3c8fe3c79bcdae4d90e3726054fac5cca8ac32 upstream.

WARNING: suspicious RCU usage
5.2.0-rc2-00605-g2638eb8b50cfc #1 Not tainted
drivers/net/plip/plip.c:1110 suspicious rcu_dereference_check() usage!

plip_open is called with RTNL held, switch to the correct helper.

Fixes: 2638eb8b50cf ("net: ipv4: provide __rcu annotation for ifa_list")
Reported-by: kernel test robot <oliver.sang@...el.com>
Signed-off-by: Florian Westphal <fw@...len.de>
Link: https://lore.kernel.org/r/20220807115304.13257-1-fw@strlen.de
Signed-off-by: Jakub Kicinski <kuba@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/net/plip/plip.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/plip/plip.c
+++ b/drivers/net/plip/plip.c
@@ -1107,7 +1107,7 @@ plip_open(struct net_device *dev)
 		/* Any address will do - we take the first. We already
 		   have the first two bytes filled with 0xfc, from
 		   plip_init_dev(). */
-		const struct in_ifaddr *ifa = rcu_dereference(in_dev->ifa_list);
+		const struct in_ifaddr *ifa = rtnl_dereference(in_dev->ifa_list);
 		if (ifa != NULL) {
 			memcpy(dev->dev_addr+2, &ifa->ifa_local, 4);
 		}