From: Xiyu Yang <xiyuyang19@fudan.edu.cn>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jiri Slaby <jslaby@suse.com>,
linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: yuanxzhang@fudan.edu.cn, kjlu@umn.edu,
Xiyu Yang <xiyuyang19@fudan.edu.cn>,
Xin Tan <tanxin.ctf@gmail.com>
Subject: [PATCH] tty: serial_core: Fix uart_state refcnt leak when the port startup
Date: Sat, 13 Jun 2020 20:52:18 +0800 [thread overview]
Message-ID: <1592052738-95202-1-git-send-email-xiyuyang19@fudan.edu.cn> (raw)
uart_port_startup() invokes uart_port_lock(), which returns a reference
of the uart_port object if increases the refcount of the uart_state
object successfully or returns NULL if fails.
However, uart_port_startup() don't take the return value of
uart_port_lock() as the new uart_port object to "uport" and use the old
"uport" instead to balance refcount in uart_port_unlock(), which may
cause a redundant decrement of refcount occurred when the new "uport"
equals to NULL and then cause a potential memory leak.
Fix this issue by update the "uport" object to the return value of
uart_port_lock() when invoking uart_port_lock().
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
---
drivers/tty/serial/serial_core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 57840cf90388..968fd619aec0 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -205,7 +205,7 @@ static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
if (!page)
return -ENOMEM;
- uart_port_lock(state, flags);
+ uport = uart_port_lock(state, flags);
if (!state->xmit.buf) {
state->xmit.buf = (unsigned char *) page;
uart_circ_clear(&state->xmit);
--
2.7.4
next reply other threads:[~2020-06-13 12:52 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-13 12:52 Xiyu Yang [this message]
2020-06-24 9:34 ` [PATCH] tty: serial_core: Fix uart_state refcnt leak when the port startup Greg Kroah-Hartman
2020-06-24 9:42 ` Jiri Slaby
2020-06-27 11:43 ` Greg Kroah-Hartman
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