gpiolib: cdev: Set lineevent_state::irq after IRQ register successfully

commit 69bef19d6b9700e96285f4b4e28691cda3dcd0d1 upstream.

When running gpio test on nxp-ls1028 platform with below command
gpiomon --num-events=3 --rising-edge gpiochip1 25
There will be a warning trace as below:
Call trace:
free_irq+0x204/0x360
lineevent_free+0x64/0x70
gpio_ioctl+0x598/0x6a0
__arm64_sys_ioctl+0xb4/0x100
invoke_syscall+0x5c/0x130
......
el0t_64_sync+0x1a0/0x1a4
The reason of this issue is that calling request_threaded_irq()
function failed, and then lineevent_free() is invoked to release
the resource. Since the lineevent_state::irq was already set, so
the subsequent invocation of free_irq() would trigger the above
warning call trace. To fix this issue, set the lineevent_state::irq
after the IRQ register successfully.

Fixes: 468242724143 ("gpiolib: cdev: refactor lineevent cleanup into lineevent_free")
Cc: stable@vger.kernel.org
Signed-off-by: Meng Li <Meng.Li@windriver.com>
Reviewed-by: Kent Gibson <warthog618@gmail.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
index 2613881a66e662beccd0b8b51f98133ea52114ca..381cfa26a4a1a0881a56616431af1c1ebbee4a5f 100644 (file)
--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -1769,7 +1769,6 @@ static int lineevent_create(struct gpio_device *gdev, void __user *ip)
                ret = -ENODEV;
                goto out_free_le;
        }
-       le->irq = irq;
 
        if (eflags & GPIOEVENT_REQUEST_RISING_EDGE)
                irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
@@ -1783,7 +1782,7 @@ static int lineevent_create(struct gpio_device *gdev, void __user *ip)
        init_waitqueue_head(&le->wait);
 
        /* Request a thread to read the events */
-       ret = request_threaded_irq(le->irq,
+       ret = request_threaded_irq(irq,
                                   lineevent_irq_handler,
                                   lineevent_irq_thread,
                                   irqflags,
@@ -1792,6 +1791,8 @@ static int lineevent_create(struct gpio_device *gdev, void __user *ip)
        if (ret)
                goto out_free_le;
 
+       le->irq = irq;
+
        fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
        if (fd < 0) {
                ret = fd;