2022-11-10 15:09:02

by Yongqiang Liu

Subject: [PATCH] cpufreq: Init completion before kobject_init_and_add()

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: 4ebe36c94aed ("cpufreq: Fix kobject memleak")
Signed-off-by: Yongqiang Liu <[email protected]>
---
drivers/cpufreq/cpufreq.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 69b3d61852ac..7e56a42750ea 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1207,6 +1207,7 @@ 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) {
@@ -1245,7 +1246,6 @@ 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;
--
2.25.1

2022-11-14 04:03:09

by Viresh Kumar

Subject: Re: [PATCH] cpufreq: Init completion before kobject_init_and_add()

On 10-11-22, 14:23, Yongqiang Liu wrote:
> 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: 4ebe36c94aed ("cpufreq: Fix kobject memleak")
> Signed-off-by: Yongqiang Liu <[email protected]>
> ---
> drivers/cpufreq/cpufreq.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index 69b3d61852ac..7e56a42750ea 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -1207,6 +1207,7 @@ 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) {
> @@ -1245,7 +1246,6 @@ 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;

Acked-by: Viresh Kumar <[email protected]>

--
viresh

2022-11-30 19:37:28

by Rafael J. Wysocki

Subject: Re: [PATCH] cpufreq: Init completion before kobject_init_and_add()

On Mon, Nov 14, 2022 at 4:23 AM Viresh Kumar <[email protected]> wrote:
>
> On 10-11-22, 14:23, Yongqiang Liu wrote:
> > 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: 4ebe36c94aed ("cpufreq: Fix kobject memleak")
> > Signed-off-by: Yongqiang Liu <[email protected]>
> > ---
> > drivers/cpufreq/cpufreq.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> > index 69b3d61852ac..7e56a42750ea 100644
> > --- a/drivers/cpufreq/cpufreq.c
> > +++ b/drivers/cpufreq/cpufreq.c
> > @@ -1207,6 +1207,7 @@ 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) {
> > @@ -1245,7 +1246,6 @@ 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;
>
> Acked-by: Viresh Kumar <[email protected]>

Applied as 6.2 material, thanks!