linux-kernel - [PATCH 1/2] can: m_can: m_can_plat_probe(): free can

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Message-Id: <20210205072559.13241-1-xulin.sun@windriver.com>
Date:   Fri,  5 Feb 2021 15:25:58 +0800
From:   Xulin Sun <xulin.sun@...driver.com>
To:     wg@...ndegger.com, mkl@...gutronix.de
Cc:     dmurphy@...com, sriram.dash@...sung.com, kuba@...nel.org,
        davem@...emloft.net, linux-can@...r.kernel.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        xulin.sun@...driver.com, xulinsun@...il.com
Subject: [PATCH 1/2] can: m_can: m_can_plat_probe(): free can_net device in case probe fails

The can_net device is allocated through kvzalloc(), if the subsequent probe
cases fail to initialize, it should free the can_net device that has been
successfully allocated before.

To fix below memory leaks call trace:

unreferenced object 0xfffffc08418b0000 (size 32768):
comm "kworker/0:1", pid 22, jiffies 4294893966 (age 931.976s)
hex dump (first 32 bytes):
63 61 6e 25 64 00 00 00 00 00 00 00 00 00 00 00 can%d...........
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<000000003faec9cc>] __kmalloc+0x1a4/0x3e0
[<00000000560b1cad>] kvmalloc_node+0xa0/0xb0
[<0000000093bada32>] alloc_netdev_mqs+0x60/0x380
[<0000000041ddbb53>] alloc_candev_mqs+0x6c/0x14c
[<00000000d08c7529>] m_can_class_allocate_dev+0x64/0x18c
[<000000009fef1617>] m_can_plat_probe+0x2c/0x1f4
[<000000006fdcc497>] platform_drv_probe+0x5c/0xb0
[<00000000fd0f0726>] really_probe+0xec/0x41c
[<000000003ffa5158>] driver_probe_device+0x60/0xf0
[<000000005986c77e>] __device_attach_driver+0xb0/0x100
[<00000000757823bc>] bus_for_each_drv+0x8c/0xe0
[<0000000059253919>] __device_attach+0xdc/0x180
[<0000000035c2b9f1>] device_initial_probe+0x28/0x34
[<0000000082e2c85c>] bus_probe_device+0xa4/0xb0
[<00000000cc6181c3>] deferred_probe_work_func+0x7c/0xb0
[<0000000001b85f22>] process_one_work+0x1ec/0x480

Signed-off-by: Xulin Sun <xulin.sun@...driver.com>
---
 drivers/net/can/m_can/m_can_platform.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/net/can/m_can/m_can_platform.c b/drivers/net/can/m_can/m_can_platform.c
index 38ea5e600fb8..0a2655c94018 100644
--- a/drivers/net/can/m_can/m_can_platform.c
+++ b/drivers/net/can/m_can/m_can_platform.c
@@ -67,8 +67,10 @@ static int m_can_plat_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
-	if (!priv)
-		return -ENOMEM;
+	if (!priv) {
+		ret = -ENOMEM;
+		goto failed_ret;
+	}
 
 	mcan_class->device_data = priv;
 
@@ -113,7 +115,11 @@ static int m_can_plat_probe(struct platform_device *pdev)
 
 	ret = m_can_class_register(mcan_class);
 
+	return ret;
+
 failed_ret:
+	free_candev(mcan_class->net);
+
 	return ret;
 }
 
-- 
2.17.1