Add a proper NULL check for the kmalloc() return value in syslog_show().
If memory allocation fails, syslog would be NULL and passing it to
misc_syslog() could lead to a NULL pointer dereference.

Signed-off-by: Li Jun <lijun01@kylinos.cn>
---
 drivers/firmware/imx/sm-misc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/firmware/imx/sm-misc.c b/drivers/firmware/imx/sm-misc.c
index ac9af824c2d4..fb8d7bdb5b08 100644
--- a/drivers/firmware/imx/sm-misc.c
+++ b/drivers/firmware/imx/sm-misc.c
@@ -79,6 +79,9 @@ static int syslog_show(struct seq_file *file, void *priv)
 	u16 size = SZ_4K / 4;
 	int ret;
 
+	if (!syslog)
+		return -ENOMEM;
+
 	if (!ph)
 		return -ENODEV;
 
-- 
2.25.1