soc: fsl: dpaa2-console: free buffer before returning from dpaa2_console_read

stable inclusion
from stable-5.10.80
commit 41968262bb24772280a0b6fbc808cf740ae961d4
bugzilla: 185821 https://gitee.com/openeuler/kernel/issues/I4L7CG

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=41968262bb24772280a0b6fbc808cf740ae961d4

--------------------------------

[ Upstream commit 8120bd46 ]

Free the kbuf buffer before returning from the dpaa2_console_read()
function. The variable no longer goes out of scope, leaking the storage
it points to.

Fixes: c93349d8 ("soc: fsl: add DPAA2 console support")
Signed-off-by: NRobert-Ionut Alexa <robert-ionut.alexa@nxp.com>
Signed-off-by: NIoana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: NLi Yang <leoyang.li@nxp.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Reviewed-by: NWeilong Chen <chenweilong@huawei.com>
Acked-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/soc/fsl/dpaa2-console.c

@@ -231,6 +231,7 @@ static ssize_t dpaa2_console_read(struct file *fp, char __user *buf,
 	cd->cur_ptr += bytes;
 	written += bytes;
 
+	kfree(kbuf);
 	return written;
 
 err_free_buf: