usb: typec: tcpm: fix logbuffer index is wrong if _tcpm_log is re-entered

[mirror_ubuntu-bionic-kernel.git] / drivers / usb / typec / tcpm.c

diff --git a/drivers/usb/typec/tcpm.c b/drivers/usb/typec/tcpm.c
index c166fc77dfb84e3547dbd3243caa69939b5b0275..4c21d1beb00d92793b7b449d42a37224bb112faa 100644 (file)
--- a/drivers/usb/typec/tcpm.c
+++ b/drivers/usb/typec/tcpm.c
@@ -386,17 +386,18 @@ static void _tcpm_log(struct tcpm_port *port, const char *fmt, va_list args)
        u64 ts_nsec = local_clock();
        unsigned long rem_nsec;
 
+       mutex_lock(&port->logbuffer_lock);
        if (!port->logbuffer[port->logbuffer_head]) {
                port->logbuffer[port->logbuffer_head] =
                                kzalloc(LOG_BUFFER_ENTRY_SIZE, GFP_KERNEL);
-               if (!port->logbuffer[port->logbuffer_head])
+               if (!port->logbuffer[port->logbuffer_head]) {
+                       mutex_unlock(&port->logbuffer_lock);
                        return;
+               }
        }
 
        vsnprintf(tmpbuffer, sizeof(tmpbuffer), fmt, args);
 
-       mutex_lock(&port->logbuffer_lock);
-
        if (tcpm_log_full(port)) {
                port->logbuffer_head = max(port->logbuffer_head - 1, 0);
                strcpy(tmpbuffer, "overflow");