drivers/serial: fix deadlock when executing rexec in a user task

CPU0 CPU1 task:nsh_main task:user_app rexecd nsh_consolemain system uart_read rexec --- got recv.lock poll --- uart_poll rpmsg_socket_poll rpmsg_socket_close wait recvsem get recv.lock poll_notify deadlock routine work the error accurs in CPU0 when waiting console input resolve: unlock recv.lock when waiting recvsem Signed-off-by: fangpeina <[email protected]>
hujun260 · Sep 14, 2024 · 11f06eb · 11f06eb
1 parent 10e7d8f
commit 11f06eb
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/drivers/serial/serial.c b/drivers/serial/serial.c
@@ -1052,15 +1052,19 @@ static ssize_t uart_read(FAR struct file *filep,
                   dev->minrecv = MIN(buflen - recvd, dev->minread - recvd);
                   if (dev->timeout)
                     {
+                      nxmutex_unlock(&dev->recv.lock);
                       ret = nxsem_tickwait(&dev->recvsem,
                                            DSEC2TICK(dev->timeout));
                     }
                   else
 #endif
                     {
+                      nxmutex_unlock(&dev->recv.lock);
                       ret = nxsem_wait(&dev->recvsem);
                     }
 
+                  nxmutex_lock(&dev->recv.lock);
+
 #ifdef CONFIG_SERIAL_TERMIOS
                   dev->minrecv = dev->minread;
 #endif