[PATCH] mmc: sdio_uart: fix xmit_fifo leak when the port table is full

From: Felix Gu

Date: Fri Aug 21 2026 - 14:59:15 EST


sdio_uart_add_port() allocates the transmit fifo before claiming a
slot in sdio_uart_table[]. When all UART_NR slots are taken, it
returns -EBUSY with the fifo still allocated, but the probe error
path only kfree()s the port, leaking the transmit fifo.

Free the fifo in the failure path of sdio_uart_add_port() itself so
the function retains nothing on error.

Fixes: 8b197a5ce7a7 ("sdio_uart: Use kfifo instead of the messy circ stuff")
Signed-off-by: Felix Gu <ustc.gu@xxxxxxxxx>
---
drivers/mmc/core/sdio_uart.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/mmc/core/sdio_uart.c b/drivers/mmc/core/sdio_uart.c
index 7fd5dedf3ac0..705163c42972 100644
--- a/drivers/mmc/core/sdio_uart.c
+++ b/drivers/mmc/core/sdio_uart.c
@@ -104,6 +104,9 @@ static int sdio_uart_add_port(struct sdio_uart_port *port)
}
spin_unlock(&sdio_uart_table_lock);

+ if (ret)
+ kfifo_free(&port->xmit_fifo);
+
return ret;
}


---
base-commit: 903c1cf6dff9964e71eda98a39e2e5d442050472
change-id: 20260822-sdio_uart-a702d7cc5eb4

Best regards,
--
Felix Gu <ustc.gu@xxxxxxxxx>