From 18f038e6bfb715310526ac05e4f20e55683471de Mon Sep 17 00:00:00 2001 From: Sudip Mukherjee Date: Sat, 27 Feb 2016 17:33:35 +0530 Subject: [PATCH] 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: [] sysfs_remove_file_ns+0x8/0x20 with part of the call trace as: [ 942.001544] Call Trace: [ 942.001555] [] driver_remove_file+0x16/0x20 [ 942.001571] [] dgnc_remove_driver_sysfiles+0x18/0x40 [dgnc] [ 942.001575] [] dgnc_cleanup_module+0x47/0x260 [dgnc] [ 942.001577] [] ? 0xf86cb000 [ 942.001580] [] 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: Navy Cheng Signed-off-by: Sudip Mukherjee Signed-off-by: Greg Kroah-Hartman --- drivers/staging/dgnc/dgnc_driver.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/drivers/staging/dgnc/dgnc_driver.c b/drivers/staging/dgnc/dgnc_driver.c index 22a92d1..4eb410e 100644 --- a/drivers/staging/dgnc/dgnc_driver.c +++ b/drivers/staging/dgnc/dgnc_driver.c @@ -125,12 +125,7 @@ static struct pci_driver dgnc_driver = { * ************************************************************************/ -/* - * dgnc_cleanup_module() - * - * Module unload. This is where it all ends. - */ -static void dgnc_cleanup_module(void) +static void cleanup(bool sysfiles) { int i; unsigned long flags; @@ -142,7 +137,8 @@ static void dgnc_cleanup_module(void) /* Turn off poller right away. */ del_timer_sync(&dgnc_poll_timer); - dgnc_remove_driver_sysfiles(&dgnc_driver); + if (sysfiles) + dgnc_remove_driver_sysfiles(&dgnc_driver); device_destroy(dgnc_class, MKDEV(dgnc_Major, 0)); class_destroy(dgnc_class); @@ -155,7 +151,16 @@ static void dgnc_cleanup_module(void) } 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); } @@ -182,7 +187,7 @@ static int __init dgnc_init_module(void) rc = pci_register_driver(&dgnc_driver); if (rc) { pr_warn("WARNING: dgnc driver load failed. No Digi Neo or Classic boards found.\n"); - dgnc_cleanup_module(); + cleanup(false); return rc; } dgnc_create_driver_sysfiles(&dgnc_driver); -- 2.7.4