[PATCH v2 RESEND 2/3] powerpc/pseries: switch to dynamic ibmebus root device
From: Johan Hovold <johan@kernel.org>
Date: 2026-08-12 14:20:41
Also in:
lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
Driver core expects devices to be dynamically allocated and will, for example, complain loudly if a device that lacks a release function is ever freed. Use root_device_register() to allocate and register the root device instead of open coding using a static device. Also add the missing sanity check when registering ibmebus devices to avoid use-after-free if the bus failed to register (which would previously have triggered a bunch of use-after-free warnings). Signed-off-by: Johan Hovold <johan@kernel.org> --- arch/powerpc/platforms/pseries/ibmebus.c | 39 ++++++++++++++---------- 1 file changed, 23 insertions(+), 16 deletions(-)
diff --git a/arch/powerpc/platforms/pseries/ibmebus.c b/arch/powerpc/platforms/pseries/ibmebus.c
index 2d0f991da2c8..48076fe6ab30 100644
--- a/arch/powerpc/platforms/pseries/ibmebus.c
+++ b/arch/powerpc/platforms/pseries/ibmebus.c@@ -52,9 +52,7 @@ #include <asm/ibmebus.h> #include <asm/machdep.h> -static struct device ibmebus_bus_device = { /* fake "parent" device */ - .init_name = "ibmebus", -}; +static struct device *ibmebus_bus_device; /* fake "parent" device */ const struct bus_type ibmebus_bus_type;
@@ -172,7 +170,10 @@ static int ibmebus_create_device(struct device_node *dn) struct platform_device *dev; int ret; - dev = of_device_alloc(dn, NULL, &ibmebus_bus_device); + if (!ibmebus_bus_device) + return -ENOENT; + + dev = of_device_alloc(dn, NULL, ibmebus_bus_device); if (!dev) return -ENOMEM;
@@ -448,6 +449,7 @@ EXPORT_SYMBOL(ibmebus_bus_type); static int __init ibmebus_bus_init(void) { + struct device *root; int err; printk(KERN_INFO "IBM eBus Device Driver\n");
@@ -459,23 +461,28 @@ static int __init ibmebus_bus_init(void) return err; } - err = device_register(&ibmebus_bus_device); - if (err) { - printk(KERN_WARNING "%s: device_register returned %i\n", + root = root_device_register("ibmebus"); + if (IS_ERR(root)) { + err = PTR_ERR(root); + printk(KERN_WARNING "%s: root_device_register returned %i\n", __func__, err); - put_device(&ibmebus_bus_device); - bus_unregister(&ibmebus_bus_type); - - return err; + goto err_deregister_bus; } + ibmebus_bus_device = root; + err = ibmebus_create_devices(ibmebus_matches); - if (err) { - device_unregister(&ibmebus_bus_device); - bus_unregister(&ibmebus_bus_type); - return err; - } + if (err) + goto err_deregister_root; return 0; + +err_deregister_root: + ibmebus_bus_device = NULL; + root_device_unregister(root); +err_deregister_bus: + bus_unregister(&ibmebus_bus_type); + + return err; } machine_postcore_initcall(pseries, ibmebus_bus_init);
--
2.54.0