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From:   Johannes Berg <johannes@sipsolutions.net>
To:     linux-wireless@vger.kernel.org
Cc:     Harald Arnesen <harald@skogtun.org>,
        Arend van Spriel <aspriel@gmail.com>,
        =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <zajec5@gmail.com>,
        Johannes Berg <johannes.berg@intel.com>
Subject: [RFC PATCH] brcmfmac: don't take RTNL if already locked
Date:   Mon, 26 Apr 2021 21:29:07 +0200
Message-Id: <20210426212905.6b0f78581429.I2ee37448e499091b3ec0b23d642e3113ef670a8e@changeid>
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From: Johannes Berg <johannes.berg@intel.com>

We should not take the RTNL if we come here already with the
RTNL held, so don't take it again.

The Fixes tag below might not be completely accurate, that
might just have made the problem obvious by showing that the
function can be called with RTNL already held.

Fixes: b50ddfa8530e ("brcmfmac: fix lockup when removing P2P interface after event timeout")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
index ea78fe527c5d..ce9d8781b62b 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
@@ -926,9 +926,11 @@ static void brcmf_del_if(struct brcmf_pub *drvr, s32 bsscfgidx,
 	if (ifp->ndev) {
 		if (bsscfgidx == 0) {
 			if (ifp->ndev->netdev_ops == &brcmf_netdev_ops_pri) {
-				rtnl_lock();
+				if (!locked)
+					rtnl_lock();
 				brcmf_netdev_stop(ifp->ndev);
-				rtnl_unlock();
+				if (!locked)
+					rtnl_unlock();
 			}
 		} else {
 			netif_stop_queue(ifp->ndev);
-- 
2.30.2