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From:   Hans de Goede <hdegoede@redhat.com>
To:     Arend van Spriel <aspriel@gmail.com>,
        Franky Lin <franky.lin@broadcom.com>,
        Hante Meuleman <hante.meuleman@broadcom.com>,
        Kalle Valo <kvalo@codeaurora.org>,
        Chi-Hsien Lin <chi-hsien.lin@infineon.com>,
        Chung-hsien Hsu <chung-hsien.hsu@infineon.com>,
        Wright Feng <wright.feng@infineon.com>
Cc:     Hans de Goede <hdegoede@redhat.com>,
        linux-wireless@vger.kernel.org,
        brcm80211-dev-list.pdl@broadcom.com,
        SHA-cyfmac-dev-list@infineon.com,
        Johannes Berg <johannes.berg@intel.com>
Subject: [PATCH 5.12 regression fix] brcmfmac: p2p: Fix recently introduced deadlock issue
Date:   Sat, 13 Mar 2021 15:36:35 +0100
Message-Id: <20210313143635.109154-1-hdegoede@redhat.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Commit a05829a7222e ("cfg80211: avoid holding the RTNL when calling the
driver") replaced the rtnl_lock parameter passed to various brcmf
functions with just lock, because since that commit it is not just
about the rtnl_lock but also about the wiphy_lock .

During this search/replace the "if (!rtnl_locked)" check in brcmfmac/p2p.c
was accidentally replaced with "if (locked)", dropping the inversion of
the check. This causes the code to now call rtnl_lock() while already
holding the lock, causing a deadlock.

Add back the "!" to the if-condition to fix this.

Cc: Johannes Berg <johannes.berg@intel.com>
Fixes: a05829a7222e ("cfg80211: avoid holding the RTNL when calling the driver")
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c
index 6d30a0fcecea..34cd8a7401fe 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c
@@ -2439,7 +2439,7 @@ void brcmf_p2p_ifp_removed(struct brcmf_if *ifp, bool locked)
 	vif = ifp->vif;
 	cfg = wdev_to_cfg(&vif->wdev);
 	cfg->p2p.bss_idx[P2PAPI_BSSCFG_DEVICE].vif = NULL;
-	if (locked) {
+	if (!locked) {
 		rtnl_lock();
 		wiphy_lock(cfg->wiphy);
 		cfg80211_unregister_wdev(&vif->wdev);
-- 
2.30.2