diff options
| author | Sumeet Pawnikar <sumeet4linux@gmail.com> | 2025-12-06 00:32:16 +0530 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2025-12-15 12:29:11 +0100 |
| commit | 7bda1910c4bccd4b8d4726620bb3d6bbfb62286e (patch) | |
| tree | e084db4e2270398ab0f0a3385aba53212dcfa0d8 /drivers/powercap | |
| parent | 8f0b4cce4481fb22653697cced8d0d04027cb1e8 (diff) | |
powercap: fix race condition in register_control_type()
The device becomes visible to userspace via device_register()
even before it fully initialized by idr_init(). If userspace
or another thread tries to register a zone immediately after
device_register(), the control_type_valid() will fail because
the control_type is not yet in the list. The IDR is not yet
initialized, so this race condition causes zone registration
failure.
Move idr_init() and list addition before device_register()
fix the race condition.
Signed-off-by: Sumeet Pawnikar <sumeet4linux@gmail.com>
[ rjw: Subject adjustment, empty line added ]
Link: https://patch.msgid.link/20251205190216.5032-1-sumeet4linux@gmail.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/powercap')
| -rw-r--r-- | drivers/powercap/powercap_sys.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/drivers/powercap/powercap_sys.c b/drivers/powercap/powercap_sys.c index 4112a0097338..d14b36b75189 100644 --- a/drivers/powercap/powercap_sys.c +++ b/drivers/powercap/powercap_sys.c @@ -625,17 +625,23 @@ struct powercap_control_type *powercap_register_control_type( INIT_LIST_HEAD(&control_type->node); control_type->dev.class = &powercap_class; dev_set_name(&control_type->dev, "%s", name); - result = device_register(&control_type->dev); - if (result) { - put_device(&control_type->dev); - return ERR_PTR(result); - } idr_init(&control_type->idr); mutex_lock(&powercap_cntrl_list_lock); list_add_tail(&control_type->node, &powercap_cntrl_list); mutex_unlock(&powercap_cntrl_list_lock); + result = device_register(&control_type->dev); + if (result) { + mutex_lock(&powercap_cntrl_list_lock); + list_del(&control_type->node); + mutex_unlock(&powercap_cntrl_list_lock); + + idr_destroy(&control_type->idr); + put_device(&control_type->dev); + return ERR_PTR(result); + } + return control_type; } EXPORT_SYMBOL_GPL(powercap_register_control_type); |