diff options
| author | Alexandre Belloni <alexandre.belloni@bootlin.com> | 2018-08-16 09:39:41 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-09-12 09:46:46 +0200 |
| commit | ae61cf5b9913027c6953a79ed3894da4f47061bd (patch) | |
| tree | 48996f836e052982c5fcfa35a57e5302cfda4bb8 /drivers/uio/uio.c | |
| parent | f25a7ece08bdb1f2b3c4bbeae942682fc3a99dde (diff) | |
uio: ensure class is registered before devices
When both uio and the uio drivers are built in the kernel, it is possible
for a driver to register devices before the uio class is registered.
This may result in a NULL pointer dereference later on in
get_device_parent() when accessing the class glue_dirs spinlock.
The trace looks like that:
Unable to handle kernel NULL pointer dereference at virtual address 00000140
[...]
[<ffff0000089cc234>] _raw_spin_lock+0x14/0x48
[<ffff0000084f56bc>] device_add+0x154/0x6a0
[<ffff0000084f5e48>] device_create_groups_vargs+0x120/0x128
[<ffff0000084f5edc>] device_create+0x54/0x60
[<ffff0000086e72c0>] __uio_register_device+0x120/0x4a8
[<ffff000008528b7c>] jaguar2_pci_probe+0x2d4/0x558
[<ffff0000083fc18c>] local_pci_probe+0x3c/0xb8
[<ffff0000083fd81c>] pci_device_probe+0x11c/0x180
[<ffff0000084f88bc>] driver_probe_device+0x22c/0x2d8
[<ffff0000084f8a24>] __driver_attach+0xbc/0xc0
[<ffff0000084f69fc>] bus_for_each_dev+0x4c/0x98
[<ffff0000084f81b8>] driver_attach+0x20/0x28
[<ffff0000084f7d08>] bus_add_driver+0x1b8/0x228
[<ffff0000084f93c0>] driver_register+0x60/0xf8
[<ffff0000083fb918>] __pci_register_driver+0x40/0x48
Return EPROBE_DEFER in that case so the driver can register the device
later.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/uio/uio.c')
| -rw-r--r-- | drivers/uio/uio.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c index 70a7981b94b3..9916edda5271 100644 --- a/drivers/uio/uio.c +++ b/drivers/uio/uio.c @@ -274,6 +274,8 @@ static struct class uio_class = { .dev_groups = uio_groups, }; +bool uio_class_registered; + /* * device functions */ @@ -876,6 +878,9 @@ static int init_uio_class(void) printk(KERN_ERR "class_register failed for uio\n"); goto err_class_register; } + + uio_class_registered = true; + return 0; err_class_register: @@ -886,6 +891,7 @@ exit: static void release_uio_class(void) { + uio_class_registered = false; class_unregister(&uio_class); uio_major_cleanup(); } @@ -912,6 +918,9 @@ int __uio_register_device(struct module *owner, struct uio_device *idev; int ret = 0; + if (!uio_class_registered) + return -EPROBE_DEFER; + if (!parent || !info || !info->name || !info->version) return -EINVAL; |