Commit f35713ba authored Apr 23, 2020 by Xiyu Yang Committed by Greg Kroah-Hartman Jun 25, 2020

staging: gasket: Fix mapping refcnt leak when register/store fails



[ Upstream commit e3436ce60cf5f5eaedda2b8c622f69feb97595e2 ]

gasket_sysfs_register_store() invokes get_mapping(), which returns a
reference of the specified gasket_sysfs_mapping object to "mapping" with
increased refcnt.

When gasket_sysfs_register_store() returns, local variable "mapping"
becomes invalid, so the refcount should be decreased to keep refcount
balanced.

The reference counting issue happens in one exception handling path of
gasket_sysfs_register_store(). When gasket_dev is NULL, the function
forgets to decrease the refcnt increased by get_mapping(), causing a
refcnt leak.

Fix this issue by calling put_mapping() when gasket_dev is NULL.

Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Link: https://lore.kernel.org/r/1587618941-13718-1-git-send-email-xiyuyang19@fudan.edu.cn


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent c42581d2

drivers/staging/gasket/gasket_sysfs.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -377,6 +377,7 @@ ssize_t gasket_sysfs_register_store(struct device *device,
		gasket_dev = mapping->gasket_dev;
		if (!gasket_dev) {
		dev_err(device, "Device driver may have been removed\n");
		put_mapping(mapping);
		return 0;
		}