When booting top-of-tree the following WARN_ON triggers in the kernel on a 15h AMD system. WARNING: CPU: 2 PID: 621 at drivers/base/dd.c:349 driver_probe_device+0x38c Modules linked in: i2c_amd756(+) amd_rng sg pcspkr parport_pc(+) parport k8 CPU: 2 PID: 621 Comm: systemd-udevd Not tainted 4.11.0-0.rc1.git0.1.el7_UNS Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./TYAN High-End Call Trace: dump_stack+0x63/0x8e __warn+0xd1/0xf0 warn_slowpath_null+0x1d/0x20 driver_probe_device+0x38c/0x470 __driver_attach+0xc9/0xf0 ? driver_probe_device+0x470/0x470 bus_for_each_dev+0x5d/0x90 driver_attach+0x1e/0x20 bus_add_driver+0x1d0/0x290 driver_register+0x60/0xe0 ? 0xffffffffa0037000 __pci_register_driver+0x4c/0x50 amd756_driver_init+0x1e/0x1000 [i2c_amd756] do_one_initcall+0x51/0x1b0 ? __vunmap+0x85/0xd0 ? do_init_module+0x27/0x1fa do_init_module+0x60/0x1fa load_module+0x15d1/0x1ad0 ? m_show+0x1c0/0x1c0 SYSC_finit_module+0xa9/0xd0 There are PCI devices that contain both a RNG and SMBUS device. The RNG device is initialized by the amd-rng driver but the driver does not register against the device. The SMBUS device is initialized by the i2c-amd756 driver and registers against the device and hits the WARN_ON() because the amd-rng driver has already allocated resources against the device. The amd-rng driver was incorrectly migrated to the device resource model (devres), and after code inspection I found that the geode-rng driver was also incorrectly migrated. These drivers are using devres but do not register a driver against the device, and both drivers are expecting a memory cleanup on a driver detach that will never happen. This results in a memory leak when the driver is unloaded and the inability to reload the driver. Revert 31b2a73c9c5f ("hwrng: amd - Migrate to managed API"), and 6e9b5e76882c ("hwrng: geode - Migrate to managed API"). Signed-off-by: Prarit Bhargava <prarit@xxxxxxxxxx> Fixes: 31b2a73c9c5f ("hwrng: amd - Migrate to managed API"). Fixes: 6e9b5e76882c ("hwrng: geode - Migrate to managed API") Cc: Matt Mackall <mpm@xxxxxxxxxxx> Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Cc: Corentin LABBE <clabbe.montjoie@xxxxxxxxx> Cc: PrasannaKumar Muralidharan <prasannatsmkumar@xxxxxxxxx> Cc: Wei Yongjun <weiyongjun1@xxxxxxxxxx> Cc: linux-crypto@xxxxxxxxxxxxxxx Cc: linux-geode@xxxxxxxxxxxxxxxxxxx Prarit Bhargava (2): hwrng: amd - Revert managed API changes hwrng: geode - Revert managed API changes drivers/char/hw_random/amd-rng.c | 42 ++++++++++++++++++++++++------ drivers/char/hw_random/geode-rng.c | 50 +++++++++++++++++++++++++----------- 2 files changed, 69 insertions(+), 23 deletions(-) -- 1.7.9.3