diff options
| author | Sumeet Pawnikar <sumeet4linux@gmail.com> | 2025-12-06 00:32:16 +0530 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-01-17 16:39:34 +0100 |
| commit | c20bbd3cf4b468b1ec5d4ffa7dd68a36de73320e (patch) | |
| tree | 23b4d8c7d3623781fecc2d12aeb8fda08213d717 | |
| parent | 368569bc546d3368ee9980ba79fc42fdff9a3365 (diff) | |
powercap: fix race condition in register_control_type()
[ Upstream commit 7bda1910c4bccd4b8d4726620bb3d6bbfb62286e ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -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 fd475e463d1f..d7dadcaa3736 100644 --- a/drivers/powercap/powercap_sys.c +++ b/drivers/powercap/powercap_sys.c @@ -624,17 +624,23 @@ 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); |