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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Maxim Mikityanskiy <maxtram95@gmail.com>,
        M Chetan Kumar <m.chetan.kumar@intel.com>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 204/530] net: wwan: iosm: Call mutex_init before locking it
Date:   Mon, 24 Oct 2022 13:29:08 +0200
Message-Id: <20221024113054.291523955@linuxfoundation.org>
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From: Maxim Mikityanskiy <maxtram95@gmail.com>

[ Upstream commit ba0fbdb95da5ddd8db457ce6ba09d16dd979a294 ]

wwan_register_ops calls wwan_create_default_link, which ends up in the
ipc_wwan_newlink callback that locks ipc_wwan->if_mutex. However, this
mutex is not yet initialized by that point. Fix it by moving mutex_init
above the wwan_register_ops call. This also makes the order of
operations in ipc_wwan_init symmetric to ipc_wwan_deinit.

Fixes: 83068395bbfc ("net: iosm: create default link via WWAN core")
Signed-off-by: Maxim Mikityanskiy <maxtram95@gmail.com>
Reviewed-by: M Chetan Kumar <m.chetan.kumar@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/wwan/iosm/iosm_ipc_wwan.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wwan/iosm/iosm_ipc_wwan.c b/drivers/net/wwan/iosm/iosm_ipc_wwan.c
index b571d9cedba4..92f064a8f837 100644
--- a/drivers/net/wwan/iosm/iosm_ipc_wwan.c
+++ b/drivers/net/wwan/iosm/iosm_ipc_wwan.c
@@ -322,15 +322,16 @@ struct iosm_wwan *ipc_wwan_init(struct iosm_imem *ipc_imem, struct device *dev)
 	ipc_wwan->dev = dev;
 	ipc_wwan->ipc_imem = ipc_imem;
 
+	mutex_init(&ipc_wwan->if_mutex);
+
 	/* WWAN core will create a netdev for the default IP MUX channel */
 	if (wwan_register_ops(ipc_wwan->dev, &iosm_wwan_ops, ipc_wwan,
 			      IP_MUX_SESSION_DEFAULT)) {
+		mutex_destroy(&ipc_wwan->if_mutex);
 		kfree(ipc_wwan);
 		return NULL;
 	}
 
-	mutex_init(&ipc_wwan->if_mutex);
-
 	return ipc_wwan;
 }
 
-- 
2.35.1