From: Vincent Wang <[email protected]>
list_del_rcu() should be used to replace list_del() in the function
_remove_list_dev(), since the opp is a rcu protected pointer.
For example, on an ARM big.Little platform of spreadtrum, there are
little cluster, big cluster and gpu using pm_opp. And the opp_table
of big cluster will be removed when big cluster is removed, which
is implemented in the cpufreq driver. Sometimes an issue maybe occur:
[ 237.647758] c0 Unable to handle kernel paging request at virtual address dead000000000110
[ 237.647776] c0 pgd = ffffffc073e78000
[ 237.647786] c0 [dead000000000110] *pgd=0000000000000000, *pud=0000000000000000
[ 237.647808] c0 Internal error: Oops: 96000004 [#1] PREEMPT SMP
[ 237.653535] c0 Modules linked in: sprdwl_ng(O) mtty marlin2_fm mali_kbase(O)
[ 237.653569] c0 CPU: 0 PID: 38 Comm: kworker/u12:1 Tainted: G S W O 4.4.83+ #1
[ 237.653578] c0 Hardware name: Spreadtrum SP9850KHsmt 1h10 Board (DT)
[ 237.653594] c0 Workqueue: devfreq_wq devfreq_monitor
[ 237.653605] c0 task: ffffffc0babd0d80 task.stack: ffffffc0badbc000
[ 237.653619] c0 PC is at _find_device_opp+0x58/0xac
[ 237.653629] c0 LR is at dev_pm_opp_find_freq_ceil+0x2c/0xb8
[ 237.921294] c0 Call trace:
[ 237.921425] c0 [<ffffff80085362b0>] _find_device_opp+0x58/0xac
[ 237.921437] c0 [<ffffff8008536560>] dev_pm_opp_find_freq_ceil+0x2c/0xb8
[ 237.921452] c0 [<ffffff80088760f4>] devfreq_recommended_opp+0x54/0x7c
[ 237.921494] c0 [<ffffff8000b6a96c>] kbase_wait_write_flush+0x164/0x358 [mali_kbase]
[ 237.921504] c0 [<ffffff800887485c>] update_devfreq+0x8c/0xf8
[ 237.921514] c0 [<ffffff80088749e4>] devfreq_monitor+0x34/0x94
[ 237.921529] c0 [<ffffff80080bd75c>] process_one_work+0x154/0x458
[ 237.921539] c0 [<ffffff80080be428>] worker_thread+0x134/0x4a4
[ 237.921551] c0 [<ffffff80080c4bec>] kthread+0xdc/0xf0
[ 237.921564] c0 [<ffffff8008085f20>] ret_from_fork+0x10/0x30
Cc: stable <[email protected]> # 4.4
Signed-off-by: Vincent Wang <[email protected]>
Signed-off-by: Chunyan Zhang <[email protected]>
---
This patch is only for 4.4 stable branch.
Once this patch accepted, I can cook a similar patch for 4.9 stable branch.
---
drivers/base/power/opp/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
index db6e7e5..e0eac53 100644
--- a/drivers/base/power/opp/core.c
+++ b/drivers/base/power/opp/core.c
@@ -463,7 +463,7 @@ static void _kfree_list_dev_rcu(struct rcu_head *head)
static void _remove_list_dev(struct device_list_opp *list_dev,
struct device_opp *dev_opp)
{
- list_del(&list_dev->node);
+ list_del_rcu(&list_dev->node);
call_srcu(&dev_opp->srcu_head.srcu, &list_dev->rcu_head,
_kfree_list_dev_rcu);
}
--
1.9.1
On 18-12-17, 16:32, Chunyan Zhang wrote:
> From: Vincent Wang <[email protected]>
>
> list_del_rcu() should be used to replace list_del() in the function
> _remove_list_dev(), since the opp is a rcu protected pointer.
>
> For example, on an ARM big.Little platform of spreadtrum, there are
> little cluster, big cluster and gpu using pm_opp. And the opp_table
> of big cluster will be removed when big cluster is removed, which
> is implemented in the cpufreq driver. Sometimes an issue maybe occur:
>
> [ 237.647758] c0 Unable to handle kernel paging request at virtual address dead000000000110
> [ 237.647776] c0 pgd = ffffffc073e78000
> [ 237.647786] c0 [dead000000000110] *pgd=0000000000000000, *pud=0000000000000000
> [ 237.647808] c0 Internal error: Oops: 96000004 [#1] PREEMPT SMP
> [ 237.653535] c0 Modules linked in: sprdwl_ng(O) mtty marlin2_fm mali_kbase(O)
> [ 237.653569] c0 CPU: 0 PID: 38 Comm: kworker/u12:1 Tainted: G S W O 4.4.83+ #1
> [ 237.653578] c0 Hardware name: Spreadtrum SP9850KHsmt 1h10 Board (DT)
> [ 237.653594] c0 Workqueue: devfreq_wq devfreq_monitor
> [ 237.653605] c0 task: ffffffc0babd0d80 task.stack: ffffffc0badbc000
> [ 237.653619] c0 PC is at _find_device_opp+0x58/0xac
> [ 237.653629] c0 LR is at dev_pm_opp_find_freq_ceil+0x2c/0xb8
>
> [ 237.921294] c0 Call trace:
> [ 237.921425] c0 [<ffffff80085362b0>] _find_device_opp+0x58/0xac
> [ 237.921437] c0 [<ffffff8008536560>] dev_pm_opp_find_freq_ceil+0x2c/0xb8
> [ 237.921452] c0 [<ffffff80088760f4>] devfreq_recommended_opp+0x54/0x7c
> [ 237.921494] c0 [<ffffff8000b6a96c>] kbase_wait_write_flush+0x164/0x358 [mali_kbase]
> [ 237.921504] c0 [<ffffff800887485c>] update_devfreq+0x8c/0xf8
> [ 237.921514] c0 [<ffffff80088749e4>] devfreq_monitor+0x34/0x94
> [ 237.921529] c0 [<ffffff80080bd75c>] process_one_work+0x154/0x458
> [ 237.921539] c0 [<ffffff80080be428>] worker_thread+0x134/0x4a4
> [ 237.921551] c0 [<ffffff80080c4bec>] kthread+0xdc/0xf0
> [ 237.921564] c0 [<ffffff8008085f20>] ret_from_fork+0x10/0x30
>
> Cc: stable <[email protected]> # 4.4
> Signed-off-by: Vincent Wang <[email protected]>
> Signed-off-by: Chunyan Zhang <[email protected]>
> ---
>
> This patch is only for 4.4 stable branch.
> Once this patch accepted, I can cook a similar patch for 4.9 stable branch.
>
> ---
> drivers/base/power/opp/core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
> index db6e7e5..e0eac53 100644
> --- a/drivers/base/power/opp/core.c
> +++ b/drivers/base/power/opp/core.c
> @@ -463,7 +463,7 @@ static void _kfree_list_dev_rcu(struct rcu_head *head)
> static void _remove_list_dev(struct device_list_opp *list_dev,
> struct device_opp *dev_opp)
> {
> - list_del(&list_dev->node);
> + list_del_rcu(&list_dev->node);
> call_srcu(&dev_opp->srcu_head.srcu, &list_dev->rcu_head,
> _kfree_list_dev_rcu);
Acked-by: Viresh Kumar <[email protected]>
--
viresh
On Mon, Dec 18, 2017 at 04:32:23PM +0800, Chunyan Zhang wrote:
> From: Vincent Wang <[email protected]>
>
> list_del_rcu() should be used to replace list_del() in the function
> _remove_list_dev(), since the opp is a rcu protected pointer.
>
> For example, on an ARM big.Little platform of spreadtrum, there are
> little cluster, big cluster and gpu using pm_opp. And the opp_table
> of big cluster will be removed when big cluster is removed, which
> is implemented in the cpufreq driver. Sometimes an issue maybe occur:
>
> [ 237.647758] c0 Unable to handle kernel paging request at virtual address dead000000000110
> [ 237.647776] c0 pgd = ffffffc073e78000
> [ 237.647786] c0 [dead000000000110] *pgd=0000000000000000, *pud=0000000000000000
> [ 237.647808] c0 Internal error: Oops: 96000004 [#1] PREEMPT SMP
> [ 237.653535] c0 Modules linked in: sprdwl_ng(O) mtty marlin2_fm mali_kbase(O)
> [ 237.653569] c0 CPU: 0 PID: 38 Comm: kworker/u12:1 Tainted: G S W O 4.4.83+ #1
> [ 237.653578] c0 Hardware name: Spreadtrum SP9850KHsmt 1h10 Board (DT)
> [ 237.653594] c0 Workqueue: devfreq_wq devfreq_monitor
> [ 237.653605] c0 task: ffffffc0babd0d80 task.stack: ffffffc0badbc000
> [ 237.653619] c0 PC is at _find_device_opp+0x58/0xac
> [ 237.653629] c0 LR is at dev_pm_opp_find_freq_ceil+0x2c/0xb8
>
> [ 237.921294] c0 Call trace:
> [ 237.921425] c0 [<ffffff80085362b0>] _find_device_opp+0x58/0xac
> [ 237.921437] c0 [<ffffff8008536560>] dev_pm_opp_find_freq_ceil+0x2c/0xb8
> [ 237.921452] c0 [<ffffff80088760f4>] devfreq_recommended_opp+0x54/0x7c
> [ 237.921494] c0 [<ffffff8000b6a96c>] kbase_wait_write_flush+0x164/0x358 [mali_kbase]
> [ 237.921504] c0 [<ffffff800887485c>] update_devfreq+0x8c/0xf8
> [ 237.921514] c0 [<ffffff80088749e4>] devfreq_monitor+0x34/0x94
> [ 237.921529] c0 [<ffffff80080bd75c>] process_one_work+0x154/0x458
> [ 237.921539] c0 [<ffffff80080be428>] worker_thread+0x134/0x4a4
> [ 237.921551] c0 [<ffffff80080c4bec>] kthread+0xdc/0xf0
> [ 237.921564] c0 [<ffffff8008085f20>] ret_from_fork+0x10/0x30
>
> Cc: stable <[email protected]> # 4.4
> Signed-off-by: Vincent Wang <[email protected]>
> Signed-off-by: Chunyan Zhang <[email protected]>
> ---
>
> This patch is only for 4.4 stable branch.
> Once this patch accepted, I can cook a similar patch for 4.9 stable branch.
<formletter>
This is not the correct way to submit patches for inclusion in the
stable kernel tree. Please read:
https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.
</formletter>
On 18-12-17, 10:07, Greg Kroah-Hartman wrote:
> On Mon, Dec 18, 2017 at 04:32:23PM +0800, Chunyan Zhang wrote:
> > From: Vincent Wang <[email protected]>
> >
> > list_del_rcu() should be used to replace list_del() in the function
> > _remove_list_dev(), since the opp is a rcu protected pointer.
> >
> > For example, on an ARM big.Little platform of spreadtrum, there are
> > little cluster, big cluster and gpu using pm_opp. And the opp_table
> > of big cluster will be removed when big cluster is removed, which
> > is implemented in the cpufreq driver. Sometimes an issue maybe occur:
> >
> > [ 237.647758] c0 Unable to handle kernel paging request at virtual address dead000000000110
> > [ 237.647776] c0 pgd = ffffffc073e78000
> > [ 237.647786] c0 [dead000000000110] *pgd=0000000000000000, *pud=0000000000000000
> > [ 237.647808] c0 Internal error: Oops: 96000004 [#1] PREEMPT SMP
> > [ 237.653535] c0 Modules linked in: sprdwl_ng(O) mtty marlin2_fm mali_kbase(O)
> > [ 237.653569] c0 CPU: 0 PID: 38 Comm: kworker/u12:1 Tainted: G S W O 4.4.83+ #1
> > [ 237.653578] c0 Hardware name: Spreadtrum SP9850KHsmt 1h10 Board (DT)
> > [ 237.653594] c0 Workqueue: devfreq_wq devfreq_monitor
> > [ 237.653605] c0 task: ffffffc0babd0d80 task.stack: ffffffc0badbc000
> > [ 237.653619] c0 PC is at _find_device_opp+0x58/0xac
> > [ 237.653629] c0 LR is at dev_pm_opp_find_freq_ceil+0x2c/0xb8
> >
> > [ 237.921294] c0 Call trace:
> > [ 237.921425] c0 [<ffffff80085362b0>] _find_device_opp+0x58/0xac
> > [ 237.921437] c0 [<ffffff8008536560>] dev_pm_opp_find_freq_ceil+0x2c/0xb8
> > [ 237.921452] c0 [<ffffff80088760f4>] devfreq_recommended_opp+0x54/0x7c
> > [ 237.921494] c0 [<ffffff8000b6a96c>] kbase_wait_write_flush+0x164/0x358 [mali_kbase]
> > [ 237.921504] c0 [<ffffff800887485c>] update_devfreq+0x8c/0xf8
> > [ 237.921514] c0 [<ffffff80088749e4>] devfreq_monitor+0x34/0x94
> > [ 237.921529] c0 [<ffffff80080bd75c>] process_one_work+0x154/0x458
> > [ 237.921539] c0 [<ffffff80080be428>] worker_thread+0x134/0x4a4
> > [ 237.921551] c0 [<ffffff80080c4bec>] kthread+0xdc/0xf0
> > [ 237.921564] c0 [<ffffff8008085f20>] ret_from_fork+0x10/0x30
> >
> > Cc: stable <[email protected]> # 4.4
> > Signed-off-by: Vincent Wang <[email protected]>
> > Signed-off-by: Chunyan Zhang <[email protected]>
> > ---
> >
> > This patch is only for 4.4 stable branch.
> > Once this patch accepted, I can cook a similar patch for 4.9 stable branch.
>
> <formletter>
>
> This is not the correct way to submit patches for inclusion in the
> stable kernel tree. Please read:
> https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
> for how to do this properly.
Are you worried about this not being merged upstream first ? Or something else ?
This can't be done to upstream kernel as the OPP code doesn't use RCUs anymore
and yes, this reason should have been part of the commit message to make things
clear.
--
viresh
On Mon, Dec 18, 2017 at 02:41:39PM +0530, Viresh Kumar wrote:
> On 18-12-17, 10:07, Greg Kroah-Hartman wrote:
> > On Mon, Dec 18, 2017 at 04:32:23PM +0800, Chunyan Zhang wrote:
> > > From: Vincent Wang <[email protected]>
> > >
> > > list_del_rcu() should be used to replace list_del() in the function
> > > _remove_list_dev(), since the opp is a rcu protected pointer.
> > >
> > > For example, on an ARM big.Little platform of spreadtrum, there are
> > > little cluster, big cluster and gpu using pm_opp. And the opp_table
> > > of big cluster will be removed when big cluster is removed, which
> > > is implemented in the cpufreq driver. Sometimes an issue maybe occur:
> > >
> > > [ 237.647758] c0 Unable to handle kernel paging request at virtual address dead000000000110
> > > [ 237.647776] c0 pgd = ffffffc073e78000
> > > [ 237.647786] c0 [dead000000000110] *pgd=0000000000000000, *pud=0000000000000000
> > > [ 237.647808] c0 Internal error: Oops: 96000004 [#1] PREEMPT SMP
> > > [ 237.653535] c0 Modules linked in: sprdwl_ng(O) mtty marlin2_fm mali_kbase(O)
> > > [ 237.653569] c0 CPU: 0 PID: 38 Comm: kworker/u12:1 Tainted: G S W O 4.4.83+ #1
> > > [ 237.653578] c0 Hardware name: Spreadtrum SP9850KHsmt 1h10 Board (DT)
> > > [ 237.653594] c0 Workqueue: devfreq_wq devfreq_monitor
> > > [ 237.653605] c0 task: ffffffc0babd0d80 task.stack: ffffffc0badbc000
> > > [ 237.653619] c0 PC is at _find_device_opp+0x58/0xac
> > > [ 237.653629] c0 LR is at dev_pm_opp_find_freq_ceil+0x2c/0xb8
> > >
> > > [ 237.921294] c0 Call trace:
> > > [ 237.921425] c0 [<ffffff80085362b0>] _find_device_opp+0x58/0xac
> > > [ 237.921437] c0 [<ffffff8008536560>] dev_pm_opp_find_freq_ceil+0x2c/0xb8
> > > [ 237.921452] c0 [<ffffff80088760f4>] devfreq_recommended_opp+0x54/0x7c
> > > [ 237.921494] c0 [<ffffff8000b6a96c>] kbase_wait_write_flush+0x164/0x358 [mali_kbase]
> > > [ 237.921504] c0 [<ffffff800887485c>] update_devfreq+0x8c/0xf8
> > > [ 237.921514] c0 [<ffffff80088749e4>] devfreq_monitor+0x34/0x94
> > > [ 237.921529] c0 [<ffffff80080bd75c>] process_one_work+0x154/0x458
> > > [ 237.921539] c0 [<ffffff80080be428>] worker_thread+0x134/0x4a4
> > > [ 237.921551] c0 [<ffffff80080c4bec>] kthread+0xdc/0xf0
> > > [ 237.921564] c0 [<ffffff8008085f20>] ret_from_fork+0x10/0x30
> > >
> > > Cc: stable <[email protected]> # 4.4
> > > Signed-off-by: Vincent Wang <[email protected]>
> > > Signed-off-by: Chunyan Zhang <[email protected]>
> > > ---
> > >
> > > This patch is only for 4.4 stable branch.
> > > Once this patch accepted, I can cook a similar patch for 4.9 stable branch.
> >
> > <formletter>
> >
> > This is not the correct way to submit patches for inclusion in the
> > stable kernel tree. Please read:
> > https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
> > for how to do this properly.
>
> Are you worried about this not being merged upstream first ? Or something else ?
Yes, and yes.
> This can't be done to upstream kernel as the OPP code doesn't use RCUs anymore
> and yes, this reason should have been part of the commit message to make things
> clear.
Yes, that too. But the most basic issue of not cc: stable@vger is also
a problem here :(
This needs a lot of work to go anywhere...
greg k-h
On 18 December 2017 at 17:32, Greg Kroah-Hartman
<[email protected]> wrote:
> On Mon, Dec 18, 2017 at 02:41:39PM +0530, Viresh Kumar wrote:
>> On 18-12-17, 10:07, Greg Kroah-Hartman wrote:
>> > On Mon, Dec 18, 2017 at 04:32:23PM +0800, Chunyan Zhang wrote:
>> > > From: Vincent Wang <[email protected]>
>> > >
>> > > list_del_rcu() should be used to replace list_del() in the function
>> > > _remove_list_dev(), since the opp is a rcu protected pointer.
>> > >
>> > > For example, on an ARM big.Little platform of spreadtrum, there are
>> > > little cluster, big cluster and gpu using pm_opp. And the opp_table
>> > > of big cluster will be removed when big cluster is removed, which
>> > > is implemented in the cpufreq driver. Sometimes an issue maybe occur:
>> > >
>> > > [ 237.647758] c0 Unable to handle kernel paging request at virtual address dead000000000110
>> > > [ 237.647776] c0 pgd = ffffffc073e78000
>> > > [ 237.647786] c0 [dead000000000110] *pgd=0000000000000000, *pud=0000000000000000
>> > > [ 237.647808] c0 Internal error: Oops: 96000004 [#1] PREEMPT SMP
>> > > [ 237.653535] c0 Modules linked in: sprdwl_ng(O) mtty marlin2_fm mali_kbase(O)
>> > > [ 237.653569] c0 CPU: 0 PID: 38 Comm: kworker/u12:1 Tainted: G S W O 4.4.83+ #1
>> > > [ 237.653578] c0 Hardware name: Spreadtrum SP9850KHsmt 1h10 Board (DT)
>> > > [ 237.653594] c0 Workqueue: devfreq_wq devfreq_monitor
>> > > [ 237.653605] c0 task: ffffffc0babd0d80 task.stack: ffffffc0badbc000
>> > > [ 237.653619] c0 PC is at _find_device_opp+0x58/0xac
>> > > [ 237.653629] c0 LR is at dev_pm_opp_find_freq_ceil+0x2c/0xb8
>> > >
>> > > [ 237.921294] c0 Call trace:
>> > > [ 237.921425] c0 [<ffffff80085362b0>] _find_device_opp+0x58/0xac
>> > > [ 237.921437] c0 [<ffffff8008536560>] dev_pm_opp_find_freq_ceil+0x2c/0xb8
>> > > [ 237.921452] c0 [<ffffff80088760f4>] devfreq_recommended_opp+0x54/0x7c
>> > > [ 237.921494] c0 [<ffffff8000b6a96c>] kbase_wait_write_flush+0x164/0x358 [mali_kbase]
>> > > [ 237.921504] c0 [<ffffff800887485c>] update_devfreq+0x8c/0xf8
>> > > [ 237.921514] c0 [<ffffff80088749e4>] devfreq_monitor+0x34/0x94
>> > > [ 237.921529] c0 [<ffffff80080bd75c>] process_one_work+0x154/0x458
>> > > [ 237.921539] c0 [<ffffff80080be428>] worker_thread+0x134/0x4a4
>> > > [ 237.921551] c0 [<ffffff80080c4bec>] kthread+0xdc/0xf0
>> > > [ 237.921564] c0 [<ffffff8008085f20>] ret_from_fork+0x10/0x30
>> > >
>> > > Cc: stable <[email protected]> # 4.4
>> > > Signed-off-by: Vincent Wang <[email protected]>
>> > > Signed-off-by: Chunyan Zhang <[email protected]>
>> > > ---
>> > >
>> > > This patch is only for 4.4 stable branch.
>> > > Once this patch accepted, I can cook a similar patch for 4.9 stable branch.
>> >
>> > <formletter>
>> >
>> > This is not the correct way to submit patches for inclusion in the
>> > stable kernel tree. Please read:
>> > https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
>> > for how to do this properly.
>>
>> Are you worried about this not being merged upstream first ? Or something else ?
>
> Yes, and yes.
>
>> This can't be done to upstream kernel as the OPP code doesn't use RCUs anymore
>> and yes, this reason should have been part of the commit message to make things
>> clear.
>
> Yes, that too. But the most basic issue of not cc: stable@vger is also
> a problem here :(
Sorry for the trouble, I will send this again and cc stable@vger.
Thanks,
Chunyan
>
> This needs a lot of work to go anywhere...
>
> greg k-h
On 18-12-17, 10:32, Greg Kroah-Hartman wrote:
> > > > Cc: stable <[email protected]> # 4.4
> Yes, that too. But the most basic issue of not cc: stable@vger is also
> a problem here :(
I completely missed that as Cc was marked inside the commit :)
--
viresh