From: Sudeep Holla sudeep.holla@arm.com
commit eb7b52e6db7c21400b9b2d539f9343fb6e94bd94 upstream.
When arm_ffa firmware driver module is unloaded or removed we call __ffa_devices_unregister on all the devices on the ffa bus. It must unregister all the devices instead it is currently just releasing the devices without unregistering. That is pure wrong as when we try to load the module back again, it will result in the kernel crash something like below.
-->8 CPU: 2 PID: 232 Comm: modprobe Not tainted 5.15.0-rc2+ #169 Hardware name: FVP Base RevC (DT) Call trace: dump_backtrace+0x0/0x1cc show_stack+0x18/0x64 dump_stack_lvl+0x64/0x7c dump_stack+0x18/0x38 sysfs_create_dir_ns+0xe4/0x140 kobject_add_internal+0x170/0x358 kobject_add+0x94/0x100 device_add+0x178/0x5f0 device_register+0x20/0x30 ffa_device_register+0x80/0xcc [ffa_module] ffa_setup_partitions+0x7c/0x108 [ffa_module] init_module+0x290/0x2dc [ffa_module] do_one_initcall+0xbc/0x230 do_init_module+0x58/0x304 load_module+0x15e0/0x1f68 __arm64_sys_finit_module+0xb8/0xf4 invoke_syscall+0x44/0x140 el0_svc_common+0xb4/0xf0 do_el0_svc+0x24/0x80 el0_svc+0x20/0x50 el0t_64_sync_handler+0x84/0xe4 el0t_64_sync+0x1a0/0x1a4 kobject_add_internal failed for arm-ffa-8001 with -EEXIST, don't try to register things with the same name in the same directory. ----
Fix the issue by calling device_unregister in __ffa_devices_unregister which will also take care of calling device_release(which is mapped to ffa_release_device)
Link: https://lore.kernel.org/r/20210924092859.3057562-2-sudeep.holla@arm.com Fixes: e781858488b9 ("firmware: arm_ffa: Add initial FFA bus support for device enumeration") Tested-by: Jens Wiklander jens.wiklander@linaro.org Signed-off-by: Sudeep Holla sudeep.holla@arm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/firmware/arm_ffa/bus.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/firmware/arm_ffa/bus.c +++ b/drivers/firmware/arm_ffa/bus.c @@ -127,7 +127,7 @@ static void ffa_release_device(struct de
static int __ffa_devices_unregister(struct device *dev, void *data) { - ffa_release_device(dev); + device_unregister(dev);
return 0; }