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| author | Federico Vaga <federico.vaga@gmail.com> | 2013-04-15 18:01:07 +0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-04-15 22:08:12 +0400 |
| commit | 5a65dcc04cda41f4122aacc37a5a348454645399 (patch) | |
| tree | f0c511fce40f795473eb618a9e693fe067a63c42 | |
| parent | 579a00a5c2f0a85fb4602a53e2c1beb77a646528 (diff) | |
| download | linux-5a65dcc04cda41f4122aacc37a5a348454645399.tar.xz | |
serial_core.c: add put_device() after device_find_child()
The serial core uses device_find_child() but does not drop the reference to
the retrieved child after using it. This patch add the missing put_device().
What I have done to test this issue.
I used a machine with an AMBA PL011 serial driver. I tested the patch on
next-20120408 because the last branch [next-20120415] does not boot on this
board.
For test purpose, I added some pr_info() messages to print the refcount
after device_find_child() (lines: 1937,2009), and after put_device()
(lines: 1947, 2021).
Boot the machine *without* put_device(). Then:
echo reboot > /sys/power/disk
echo disk > /sys/power/state
[ 87.058575] uart_suspend_port:1937 refcount 4
[ 87.058582] uart_suspend_port:1947 refcount 4
[ 87.098083] uart_resume_port:2009refcount 5
[ 87.098088] uart_resume_port:2021 refcount 5
echo disk > /sys/power/state
[ 103.055574] uart_suspend_port:1937 refcount 6
[ 103.055580] uart_suspend_port:1947 refcount 6
[ 103.095322] uart_resume_port:2009 refcount 7
[ 103.095327] uart_resume_port:2021 refcount 7
echo disk > /sys/power/state
[ 252.459580] uart_suspend_port:1937 refcount 8
[ 252.459586] uart_suspend_port:1947 refcount 8
[ 252.499611] uart_resume_port:2009 refcount 9
[ 252.499616] uart_resume_port:2021 refcount 9
The refcount continuously increased.
Boot the machine *with* this patch. Then:
echo reboot > /sys/power/disk
echo disk > /sys/power/state
[ 159.333559] uart_suspend_port:1937 refcount 4
[ 159.333566] uart_suspend_port:1947 refcount 3
[ 159.372751] uart_resume_port:2009 refcount 4
[ 159.372755] uart_resume_port:2021 refcount 3
echo disk > /sys/power/state
[ 185.713614] uart_suspend_port:1937 refcount 4
[ 185.713621] uart_suspend_port:1947 refcount 3
[ 185.752935] uart_resume_port:2009 refcount 4
[ 185.752940] uart_resume_port:2021 refcount 3
echo disk > /sys/power/state
[ 207.458584] uart_suspend_port:1937 refcount 4
[ 207.458591] uart_suspend_port:1947 refcount 3
[ 207.498598] uart_resume_port:2009 refcount 4
[ 207.498605] uart_resume_port:2021 refcount 3
The refcount correctly handled.
Signed-off-by: Federico Vaga <federico.vaga@gmail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/tty/serial/serial_core.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index a400002dfa84..8fbb6d22cdc8 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -1941,6 +1941,8 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport) mutex_unlock(&port->mutex); return 0; } + put_device(tty_dev); + if (console_suspend_enabled || !uart_console(uport)) uport->suspended = 1; @@ -2006,9 +2008,11 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *uport) disable_irq_wake(uport->irq); uport->irq_wake = 0; } + put_device(tty_dev); mutex_unlock(&port->mutex); return 0; } + put_device(tty_dev); uport->suspended = 0; /* |