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Commit 18f038e6 authored by Sudip Mukherjee's avatar Sudip Mukherjee Committed by Greg Kroah-Hartman
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staging: dgnc: cleanup properly 



dgnc_cleanup_module() was called when the module unloaded to do a total
cleanup and it was also called if pci_register_driver() fails. But
dgnc_cleanup_module() will try dgnc_remove_driver_sysfiles() but the
sysfiles will be created only if pci_register_driver() succeeds.
So if pci_register_driver() fails and we try dgnc_cleanup_module() then we
were getting:

[  942.001479] BUG: unable to handle kernel NULL pointer dereference at 00000018
[  942.001482] IP: [<c122c7a8>] sysfs_remove_file_ns+0x8/0x20

with part of the call trace as:

[  942.001544] Call Trace:
[  942.001555]  [<c149acc6>] driver_remove_file+0x16/0x20
[  942.001571]  [<f864a708>] dgnc_remove_driver_sysfiles+0x18/0x40 [dgnc]
[  942.001575]  [<f8643ac7>] dgnc_cleanup_module+0x47/0x260 [dgnc]
[  942.001577]  [<f86cb000>] ? 0xf86cb000
[  942.001580]  [<f86cb1e6>] dgnc_init_module+0x1e6/0x1000 [dgnc]

Lets have a separate cleanup function which will execute
dgnc_remove_driver_sysfiles() depending on the argument passed to it.

Reported-by: default avatarNavy Cheng <navych@126.com>
Signed-off-by: default avatarSudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b3ca2e08

drivers/staging/dgnc/dgnc_driver.c

+13 −8
Original line number Original line Diff line number Diff line
@@ -125,12 +125,7 @@ static struct pci_driver dgnc_driver = { 
 *

 *

 ************************************************************************/

 ************************************************************************/





/*

static void cleanup(bool sysfiles)

 * dgnc_cleanup_module()

 *

 * Module unload.  This is where it all ends.

 */

static void dgnc_cleanup_module(void)

{

{

	int i;

	int i;

	unsigned long flags;

	unsigned long flags;
@@ -142,6 +137,7 @@ static void dgnc_cleanup_module(void) 
	/* Turn off poller right away. */

	/* Turn off poller right away. */

	del_timer_sync(&dgnc_poll_timer);

	del_timer_sync(&dgnc_poll_timer);





	if (sysfiles)

		dgnc_remove_driver_sysfiles(&dgnc_driver);

		dgnc_remove_driver_sysfiles(&dgnc_driver);





	device_destroy(dgnc_class, MKDEV(dgnc_Major, 0));

	device_destroy(dgnc_class, MKDEV(dgnc_Major, 0));
@@ -155,7 +151,16 @@ static void dgnc_cleanup_module(void) 
	}

	}





	dgnc_tty_post_uninit();

	dgnc_tty_post_uninit();

}





/*

 * dgnc_cleanup_module()

 *

 * Module unload.  This is where it all ends.

 */

static void dgnc_cleanup_module(void)

{

	cleanup(true);

	pci_unregister_driver(&dgnc_driver);

	pci_unregister_driver(&dgnc_driver);

}

}
@@ -182,7 +187,7 @@ static int __init dgnc_init_module(void) 
	rc = pci_register_driver(&dgnc_driver);

	rc = pci_register_driver(&dgnc_driver);

	if (rc) {

	if (rc) {

		pr_warn("WARNING: dgnc driver load failed.  No Digi Neo or Classic boards found.\n");

		pr_warn("WARNING: dgnc driver load failed.  No Digi Neo or Classic boards found.\n");

		dgnc_cleanup_module();

		cleanup(false);

		return rc;

		return rc;

	}

	}

	dgnc_create_driver_sysfiles(&dgnc_driver);

	dgnc_create_driver_sysfiles(&dgnc_driver);