staging: gasket: interrupt: fix the missed eventfd_ctx_put() in gaske…

…t_interrupt.c

[ Upstream commit ab5b769 ]

gasket_interrupt_set_eventfd() misses to call eventfd_ctx_put() in an
error path. We check interrupt is valid before calling
eventfd_ctx_fdget() to fix it.

There is the same issue in gasket_interrupt_clear_eventfd(), Add the
missed function call to fix it.

Fixes: 9a69f50 ("drivers/staging: Gasket driver framework + Apex driver")
Signed-off-by: Jing Xiangfeng <jingxiangfeng@huawei.com>
Link: https://lore.kernel.org/r/20201112064924.99680-1-jingxiangfeng@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/staging/gasket/gasket_interrupt.c

@@ -487,14 +487,16 @@ int gasket_interrupt_system_status(struct gasket_dev *gasket_dev)
 int gasket_interrupt_set_eventfd(struct gasket_interrupt_data *interrupt_data,
 				 int interrupt, int event_fd)
 {
-	struct eventfd_ctx *ctx = eventfd_ctx_fdget(event_fd);
-
-	if (IS_ERR(ctx))
-		return PTR_ERR(ctx);
+	struct eventfd_ctx *ctx;
 
 	if (interrupt < 0 || interrupt >= interrupt_data->num_interrupts)
 		return -EINVAL;
 
+	ctx = eventfd_ctx_fdget(event_fd);
+
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
+
 	interrupt_data->eventfd_ctxs[interrupt] = ctx;
 	return 0;
 }
@@ -505,6 +507,9 @@ int gasket_interrupt_clear_eventfd(struct gasket_interrupt_data *interrupt_data,
 	if (interrupt < 0 || interrupt >= interrupt_data->num_interrupts)
 		return -EINVAL;
 
-	interrupt_data->eventfd_ctxs[interrupt] = NULL;
+	if (interrupt_data->eventfd_ctxs[interrupt]) {
+		eventfd_ctx_put(interrupt_data->eventfd_ctxs[interrupt]);
+		interrupt_data->eventfd_ctxs[interrupt] = NULL;
+	}
 	return 0;
 }