Commit f6a6ae4e authored Oct 26, 2018 by Dan Carpenter Committed by Greg Kroah-Hartman Nov 27, 2018

uio: Fix an Oops on load



commit 432798195bbce1f8cd33d1c0284d0538835e25fb upstream.

I was trying to solve a double free but I introduced a more serious
NULL dereference bug.  The problem is that if there is an IRQ which
triggers immediately, then we need "info->uio_dev" but it's not set yet.

This patch puts the original initialization back to how it was and just
sets info->uio_dev to NULL on the error path so it should solve both
the Oops and the double free.

Fixes: f019f07ecf6a ("uio: potential double frees if __uio_register_device() fails")
Reported-by: Mathias Thore <Mathias.Thore@infinera.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: stable <stable@vger.kernel.org>
Tested-by: Mathias Thore <Mathias.Thore@infinera.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 2fc77700

drivers/uio/uio.c

+5 −2

Original line number	Diff line number	Diff line
		@@ -850,6 +850,8 @@ int __uio_register_device(struct module *owner,
		if (ret)
		goto err_uio_dev_add_attributes;

		info->uio_dev = idev;

		if (info->irq && (info->irq != UIO_IRQ_CUSTOM)) {
		/*
		* Note that we deliberately don't use devm_request_irq
		@@ -861,11 +863,12 @@ int __uio_register_device(struct module *owner,
		*/
		ret = request_irq(info->irq, uio_interrupt,
		info->irq_flags, info->name, idev);
		if (ret)
		if (ret) {
		info->uio_dev = NULL;
		goto err_request_irq;
		}
		}

		info->uio_dev = idev;
		return 0;

		err_request_irq: