Commit 3cdd91a9 authored Nov 10, 2022 by Yongqiang Liu Committed by Greg Kroah-Hartman Jan 18, 2023

cpufreq: Init completion before kobject_init_and_add()



commit 5c51054896bcce1d33d39fead2af73fec24f40b6 upstream.

In cpufreq_policy_alloc(), it will call uninitialed completion in
cpufreq_sysfs_release() when kobject_init_and_add() fails. And
that will cause a crash such as the following page fault in complete:

BUG: unable to handle page fault for address: fffffffffffffff8
[..]
RIP: 0010:complete+0x98/0x1f0
[..]
Call Trace:
 kobject_put+0x1be/0x4c0
 cpufreq_online.cold+0xee/0x1fd
 cpufreq_add_dev+0x183/0x1e0
 subsys_interface_register+0x3f5/0x4e0
 cpufreq_register_driver+0x3b7/0x670
 acpi_cpufreq_init+0x56c/0x1000 [acpi_cpufreq]
 do_one_initcall+0x13d/0x780
 do_init_module+0x1c3/0x630
 load_module+0x6e67/0x73b0
 __do_sys_finit_module+0x181/0x240
 do_syscall_64+0x35/0x80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Fixes: 4ebe36c9 ("cpufreq: Fix kobject memleak")
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: 5.2+ <stable@vger.kernel.org> # 5.2+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 6ccb116e

drivers/cpufreq/cpufreq.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1204,6 +1204,7 @@ static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
		if (!zalloc_cpumask_var(&policy->real_cpus, GFP_KERNEL))
		goto err_free_rcpumask;

		init_completion(&policy->kobj_unregister);
		ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
		cpufreq_global_kobject, "policy%u", cpu);
		if (ret) {
		@@ -1242,7 +1243,6 @@ static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
		init_rwsem(&policy->rwsem);
		spin_lock_init(&policy->transition_lock);
		init_waitqueue_head(&policy->transition_wait);
		init_completion(&policy->kobj_unregister);
		INIT_WORK(&policy->update, handle_update);

		policy->cpu = cpu;