Commits
Alexandre Belloni committed ae61cf5b991
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>