drivers/mailbox/arm_mhuv2.c:702 mhuv2_receiver_interrupt() error: 'data' dereferencing possible ERR_PTR()

[Dan Carpenter]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   55f62bc873477dae2c45bbbc30b86cf3e0982f3b
commit: 5a6338cce9f4133c478d3b10b300f96dd644379a mailbox: arm_mhuv2: Add driver
config: arm64-randconfig-m031-20210221 (attached as .config)
compiler: aarch64-linux-gcc (GCC) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

smatch warnings:
drivers/mailbox/arm_mhuv2.c:702 mhuv2_receiver_interrupt() error: 'data' dereferencing possible ERR_PTR()

vim +/data +702 drivers/mailbox/arm_mhuv2.c

5a6338cce9f413 Viresh Kumar 2020-11-17  674  static irqreturn_t mhuv2_receiver_interrupt(int irq, void *arg)
5a6338cce9f413 Viresh Kumar 2020-11-17  675  {
5a6338cce9f413 Viresh Kumar 2020-11-17  676  	struct mhuv2 *mhu = arg;
5a6338cce9f413 Viresh Kumar 2020-11-17  677  	struct mbox_chan *chan = get_irq_chan_rx(mhu);
5a6338cce9f413 Viresh Kumar 2020-11-17  678  	struct device *dev = mhu->mbox.dev;
5a6338cce9f413 Viresh Kumar 2020-11-17  679  	struct mhuv2_mbox_chan_priv *priv;
5a6338cce9f413 Viresh Kumar 2020-11-17  680  	int ret = IRQ_NONE;
5a6338cce9f413 Viresh Kumar 2020-11-17  681  	void *data;
5a6338cce9f413 Viresh Kumar 2020-11-17  682  
5a6338cce9f413 Viresh Kumar 2020-11-17  683  	if (IS_ERR(chan)) {
5a6338cce9f413 Viresh Kumar 2020-11-17  684  		dev_warn(dev, "Failed to find channel for the rx interrupt\n");
5a6338cce9f413 Viresh Kumar 2020-11-17  685  		return IRQ_NONE;
5a6338cce9f413 Viresh Kumar 2020-11-17  686  	}
5a6338cce9f413 Viresh Kumar 2020-11-17  687  	priv = chan->con_priv;
5a6338cce9f413 Viresh Kumar 2020-11-17  688  
5a6338cce9f413 Viresh Kumar 2020-11-17  689  	/* Read and clear the data first */
5a6338cce9f413 Viresh Kumar 2020-11-17  690  	data = priv->ops->read_data(mhu, chan);
5a6338cce9f413 Viresh Kumar 2020-11-17  691  
5a6338cce9f413 Viresh Kumar 2020-11-17  692  	if (!chan->cl) {
5a6338cce9f413 Viresh Kumar 2020-11-17  693  		dev_warn(dev, "Received data on channel (%u) not currently attached to a mailbox client\n",
5a6338cce9f413 Viresh Kumar 2020-11-17  694  			 priv->ch_wn_idx);
5a6338cce9f413 Viresh Kumar 2020-11-17  695  	} else if (IS_ERR(data)) {
5a6338cce9f413 Viresh Kumar 2020-11-17  696  		dev_err(dev, "Failed to read data: %lu\n", PTR_ERR(data));

"data" is an error pointer.

5a6338cce9f413 Viresh Kumar 2020-11-17  697  	} else {
5a6338cce9f413 Viresh Kumar 2020-11-17  698  		mbox_chan_received_data(chan, data);
5a6338cce9f413 Viresh Kumar 2020-11-17  699  		ret = IRQ_HANDLED;
5a6338cce9f413 Viresh Kumar 2020-11-17  700  	}
5a6338cce9f413 Viresh Kumar 2020-11-17  701  
5a6338cce9f413 Viresh Kumar 2020-11-17 @702  	kfree(data);
                                                ^^^^^^^^^^^
This will crash.

5a6338cce9f413 Viresh Kumar 2020-11-17  703  	return ret;
5a6338cce9f413 Viresh Kumar 2020-11-17  704  }

---
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