Commit e9c5b0b5 authored Jul 29, 2021 by Christophe JAILLET Committed by Vinod Koul Aug 02, 2021

dmaengine: idxd: Fix a possible NULL pointer dereference



'device_driver_attach()' dereferences its first argument (i.e. 'alt_drv')
so it must not be NULL.
Simplify the error handling logic about NULL 'alt_drv' in order to be
more robust and future-proof.

Fixes: 568b2126 ("dmaengine: idxd: fix uninit var for alt_drv")
Fixes: 6e7f3ee9 ("dmaengine: idxd: move dsa_drv support to compatible mode")

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/77f0dc4f3966591d1f0cffb614a94085f8895a85.1627560174.git.christophe.jaillet@wanadoo.fr


Signed-off-by: Vinod Koul <vkoul@kernel.org>

parent ffa179ae

drivers/dma/idxd/compat.c

+4 −11

Original line number	Diff line number	Diff line
		@@ -45,23 +45,16 @@ static ssize_t bind_store(struct device_driver drv, const char buf, size_t cou
		idxd_dev = confdev_to_idxd_dev(dev);
		if (is_idxd_dev(idxd_dev)) {
		alt_drv = driver_find("idxd", bus);
		if (!alt_drv)
		return -ENODEV;
		} else if (is_idxd_wq_dev(idxd_dev)) {
		struct idxd_wq *wq = confdev_to_wq(dev);

		if (is_idxd_wq_kernel(wq)) {
		if (is_idxd_wq_kernel(wq))
		alt_drv = driver_find("dmaengine", bus);
		if (!alt_drv)
		return -ENODEV;
		} else if (is_idxd_wq_user(wq)) {
		else if (is_idxd_wq_user(wq))
		alt_drv = driver_find("user", bus);
		}
		if (!alt_drv)
		return -ENODEV;
		} else {
		return -ENODEV;
		}
		}

		rc = device_driver_attach(alt_drv, dev);
		if (rc < 0)