tree: https://kernel.googlesource.com/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev.2019.09.23a
head: 97de53b94582c208ee239178b208b8e8b9472585
commit: 39676bb72323718a9e7bab1ba9c4a68319a96f62 [62/77] rcu: Add support for debug_objects debugging for kfree_rcu()
If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <[email protected]>
Reported-by: Dan Carpenter <[email protected]>
smatch warnings:
kernel/rcu/tree.c:2882 kfree_call_rcu() warn: inconsistent returns 'irqsave:flags'.
Locked on: line 2867
Unlocked on: line 2882
git remote add rcu https://kernel.googlesource.com/pub/scm/linux/kernel/git/paulmck/linux-rcu.git
git remote update rcu
git checkout 39676bb72323718a9e7bab1ba9c4a68319a96f62
vim +2882 kernel/rcu/tree.c
5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2850) void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2851) {
5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2852) unsigned long flags;
5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2853) struct kfree_rcu_cpu *krcp;
5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2854)
5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2855) head->func = func;
5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2856)
87970ccf5a9125 Paul E. McKenney 2019-09-19 2857 local_irq_save(flags); // For safely calling this_cpu_ptr().
^^^^^^^^^^^^^^^^^^^^^
IRQs disabled.
5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2858) krcp = this_cpu_ptr(&krc);
ff8db005e371cb Paul E. McKenney 2019-09-19 2859 if (krcp->initialized)
5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2860) spin_lock(&krcp->lock);
5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2861)
87970ccf5a9125 Paul E. McKenney 2019-09-19 2862 // Queue the object but don't yet schedule the batch.
39676bb7232371 Joel Fernandes (Google 2019-09-22 2863) if (debug_rcu_head_queue(head)) {
39676bb7232371 Joel Fernandes (Google 2019-09-22 2864) // Probable double kfree_rcu(), just leak.
39676bb7232371 Joel Fernandes (Google 2019-09-22 2865) WARN_ONCE(1, "%s(): Double-freed call. rcu_head %p\n",
39676bb7232371 Joel Fernandes (Google 2019-09-22 2866) __func__, head);
39676bb7232371 Joel Fernandes (Google 2019-09-22 2867) return;
Need to re-enable before returning.
39676bb7232371 Joel Fernandes (Google 2019-09-22 2868) }
87970ccf5a9125 Paul E. McKenney 2019-09-19 2869 head->func = func;
5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2870) head->next = krcp->head;
5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2871) krcp->head = head;
5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2872)
87970ccf5a9125 Paul E. McKenney 2019-09-19 2873 // Set timer to drain after KFREE_DRAIN_JIFFIES.
ff8db005e371cb Paul E. McKenney 2019-09-19 2874 if (rcu_scheduler_active == RCU_SCHEDULER_RUNNING &&
be39848334e088 Paul E. McKenney 2019-09-22 2875 !krcp->monitor_todo) {
be39848334e088 Paul E. McKenney 2019-09-22 2876 krcp->monitor_todo = true;
5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2877) schedule_delayed_work(&krcp->monitor_work, KFREE_DRAIN_JIFFIES);
be39848334e088 Paul E. McKenney 2019-09-22 2878 }
5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2879)
ff8db005e371cb Paul E. McKenney 2019-09-19 2880 if (krcp->initialized)
5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2881) spin_unlock(&krcp->lock);
5f5046cc15d514 Joel Fernandes (Google 2019-08-05 @2882) local_irq_restore(flags);
5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2883) }
495aa969dbaef2 Andreea-Cristina Bernat 2014-03-18 2884 EXPORT_SYMBOL_GPL(kfree_call_rcu);
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
On Tue, Sep 24, 2019 at 4:05 AM Dan Carpenter <[email protected]> wrote:
>
> tree: https://kernel.googlesource.com/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev.2019.09.23a
> head: 97de53b94582c208ee239178b208b8e8b9472585
> commit: 39676bb72323718a9e7bab1ba9c4a68319a96f62 [62/77] rcu: Add support for debug_objects debugging for kfree_rcu()
>
> If you fix the issue, kindly add following tag
> Reported-by: kbuild test robot <[email protected]>
> Reported-by: Dan Carpenter <[email protected]>
>
> smatch warnings:
> kernel/rcu/tree.c:2882 kfree_call_rcu() warn: inconsistent returns 'irqsave:flags'.
> Locked on: line 2867
> Unlocked on: line 2882
>
> git remote add rcu https://kernel.googlesource.com/pub/scm/linux/kernel/git/paulmck/linux-rcu.git
> git remote update rcu
> git checkout 39676bb72323718a9e7bab1ba9c4a68319a96f62
> vim +2882 kernel/rcu/tree.c
>
> 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2850) void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
> 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2851) {
> 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2852) unsigned long flags;
> 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2853) struct kfree_rcu_cpu *krcp;
> 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2854)
> 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2855) head->func = func;
> 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2856)
> 87970ccf5a9125 Paul E. McKenney 2019-09-19 2857 local_irq_save(flags); // For safely calling this_cpu_ptr().
> ^^^^^^^^^^^^^^^^^^^^^
> IRQs disabled.
>
> 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2858) krcp = this_cpu_ptr(&krc);
> ff8db005e371cb Paul E. McKenney 2019-09-19 2859 if (krcp->initialized)
> 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2860) spin_lock(&krcp->lock);
> 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2861)
> 87970ccf5a9125 Paul E. McKenney 2019-09-19 2862 // Queue the object but don't yet schedule the batch.
> 39676bb7232371 Joel Fernandes (Google 2019-09-22 2863) if (debug_rcu_head_queue(head)) {
> 39676bb7232371 Joel Fernandes (Google 2019-09-22 2864) // Probable double kfree_rcu(), just leak.
> 39676bb7232371 Joel Fernandes (Google 2019-09-22 2865) WARN_ONCE(1, "%s(): Double-freed call. rcu_head %p\n",
> 39676bb7232371 Joel Fernandes (Google 2019-09-22 2866) __func__, head);
> 39676bb7232371 Joel Fernandes (Google 2019-09-22 2867) return;
>
> Need to re-enable before returning.
Right. At this point the system has a bug anyway since it is a
double-free. But yes, no reason to introduce more bugs. Will fix.
Thank you, Dan!
On Tue, Sep 24, 2019 at 08:15:12AM -0400, Joel Fernandes wrote:
> On Tue, Sep 24, 2019 at 4:05 AM Dan Carpenter <[email protected]> wrote:
> >
> > tree: https://kernel.googlesource.com/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev.2019.09.23a
> > head: 97de53b94582c208ee239178b208b8e8b9472585
> > commit: 39676bb72323718a9e7bab1ba9c4a68319a96f62 [62/77] rcu: Add support for debug_objects debugging for kfree_rcu()
> >
> > If you fix the issue, kindly add following tag
> > Reported-by: kbuild test robot <[email protected]>
> > Reported-by: Dan Carpenter <[email protected]>
> >
> > smatch warnings:
> > kernel/rcu/tree.c:2882 kfree_call_rcu() warn: inconsistent returns 'irqsave:flags'.
> > Locked on: line 2867
> > Unlocked on: line 2882
> >
> > git remote add rcu https://kernel.googlesource.com/pub/scm/linux/kernel/git/paulmck/linux-rcu.git
> > git remote update rcu
> > git checkout 39676bb72323718a9e7bab1ba9c4a68319a96f62
> > vim +2882 kernel/rcu/tree.c
> >
> > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2850) void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
> > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2851) {
> > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2852) unsigned long flags;
> > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2853) struct kfree_rcu_cpu *krcp;
> > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2854)
> > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2855) head->func = func;
> > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2856)
> > 87970ccf5a9125 Paul E. McKenney 2019-09-19 2857 local_irq_save(flags); // For safely calling this_cpu_ptr().
> > ^^^^^^^^^^^^^^^^^^^^^
> > IRQs disabled.
> >
> > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2858) krcp = this_cpu_ptr(&krc);
> > ff8db005e371cb Paul E. McKenney 2019-09-19 2859 if (krcp->initialized)
> > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2860) spin_lock(&krcp->lock);
> > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2861)
> > 87970ccf5a9125 Paul E. McKenney 2019-09-19 2862 // Queue the object but don't yet schedule the batch.
> > 39676bb7232371 Joel Fernandes (Google 2019-09-22 2863) if (debug_rcu_head_queue(head)) {
> > 39676bb7232371 Joel Fernandes (Google 2019-09-22 2864) // Probable double kfree_rcu(), just leak.
> > 39676bb7232371 Joel Fernandes (Google 2019-09-22 2865) WARN_ONCE(1, "%s(): Double-freed call. rcu_head %p\n",
> > 39676bb7232371 Joel Fernandes (Google 2019-09-22 2866) __func__, head);
> > 39676bb7232371 Joel Fernandes (Google 2019-09-22 2867) return;
> >
> > Need to re-enable before returning.
>
> Right. At this point the system has a bug anyway since it is a
> double-free. But yes, no reason to introduce more bugs. Will fix.
> Thank you, Dan!
What Joel said!
As long as I am doing several other reports anyway...
How does the to-be-squashed patch below look?
Thanx, Paul
------------------------------------------------------------------------
commit 39af4c08038a8a6a7b1c9804fdd2c1921d583222
Author: Paul E. McKenney <[email protected]>
Date: Tue Sep 24 09:02:00 2019 -0700
squash! rcu: Add support for debug_objects debugging for kfree_rcu()
[ paulmck: Fix IRQ per kbuild test robot <[email protected]> feedback. ]
Signed-off-by: Paul E. McKenney <[email protected]>
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 921daa7..edb7539 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2870,7 +2870,7 @@ void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
// Probable double kfree_rcu(), just leak.
WARN_ONCE(1, "%s(): Double-freed call. rcu_head %p\n",
__func__, head);
- return;
+ goto unlock_return;
}
head->func = func;
head->next = krcp->head;
@@ -2883,6 +2883,7 @@ void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
schedule_delayed_work(&krcp->monitor_work, KFREE_DRAIN_JIFFIES);
}
+unlock_return:
if (krcp->initialized)
spin_unlock(&krcp->lock);
local_irq_restore(flags);
On Tue, Sep 24, 2019 at 09:03:48AM -0700, Paul E. McKenney wrote:
> On Tue, Sep 24, 2019 at 08:15:12AM -0400, Joel Fernandes wrote:
> > On Tue, Sep 24, 2019 at 4:05 AM Dan Carpenter <[email protected]> wrote:
> > >
> > > tree: https://kernel.googlesource.com/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev.2019.09.23a
> > > head: 97de53b94582c208ee239178b208b8e8b9472585
> > > commit: 39676bb72323718a9e7bab1ba9c4a68319a96f62 [62/77] rcu: Add support for debug_objects debugging for kfree_rcu()
> > >
> > > If you fix the issue, kindly add following tag
> > > Reported-by: kbuild test robot <[email protected]>
> > > Reported-by: Dan Carpenter <[email protected]>
> > >
> > > smatch warnings:
> > > kernel/rcu/tree.c:2882 kfree_call_rcu() warn: inconsistent returns 'irqsave:flags'.
> > > Locked on: line 2867
> > > Unlocked on: line 2882
> > >
> > > git remote add rcu https://kernel.googlesource.com/pub/scm/linux/kernel/git/paulmck/linux-rcu.git
> > > git remote update rcu
> > > git checkout 39676bb72323718a9e7bab1ba9c4a68319a96f62
> > > vim +2882 kernel/rcu/tree.c
> > >
> > > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2850) void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
> > > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2851) {
> > > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2852) unsigned long flags;
> > > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2853) struct kfree_rcu_cpu *krcp;
> > > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2854)
> > > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2855) head->func = func;
> > > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2856)
> > > 87970ccf5a9125 Paul E. McKenney 2019-09-19 2857 local_irq_save(flags); // For safely calling this_cpu_ptr().
> > > ^^^^^^^^^^^^^^^^^^^^^
> > > IRQs disabled.
> > >
> > > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2858) krcp = this_cpu_ptr(&krc);
> > > ff8db005e371cb Paul E. McKenney 2019-09-19 2859 if (krcp->initialized)
> > > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2860) spin_lock(&krcp->lock);
> > > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2861)
> > > 87970ccf5a9125 Paul E. McKenney 2019-09-19 2862 // Queue the object but don't yet schedule the batch.
> > > 39676bb7232371 Joel Fernandes (Google 2019-09-22 2863) if (debug_rcu_head_queue(head)) {
> > > 39676bb7232371 Joel Fernandes (Google 2019-09-22 2864) // Probable double kfree_rcu(), just leak.
> > > 39676bb7232371 Joel Fernandes (Google 2019-09-22 2865) WARN_ONCE(1, "%s(): Double-freed call. rcu_head %p\n",
> > > 39676bb7232371 Joel Fernandes (Google 2019-09-22 2866) __func__, head);
> > > 39676bb7232371 Joel Fernandes (Google 2019-09-22 2867) return;
> > >
> > > Need to re-enable before returning.
> >
> > Right. At this point the system has a bug anyway since it is a
> > double-free. But yes, no reason to introduce more bugs. Will fix.
> > Thank you, Dan!
>
> What Joel said!
>
> As long as I am doing several other reports anyway...
>
> How does the to-be-squashed patch below look?
Hi Paul,
Sorry for the late reply due to the conference..
This patch looks Ok, the code in your tree though is slightly different mine
I think because you reworked the kfree_rcu() code for working during early
boot.
After my talk tomorrow, I will go through your rcu/dev tree in detail to
review the reworks you did in detail.
Let me know if you have the kfree_rcu() changes in a separate topic branch,
as well. So it will make reviewing easier.
thanks,
- Joel
>
> Thanx, Paul
>
> ------------------------------------------------------------------------
>
> commit 39af4c08038a8a6a7b1c9804fdd2c1921d583222
> Author: Paul E. McKenney <[email protected]>
> Date: Tue Sep 24 09:02:00 2019 -0700
>
> squash! rcu: Add support for debug_objects debugging for kfree_rcu()
>
> [ paulmck: Fix IRQ per kbuild test robot <[email protected]> feedback. ]
> Signed-off-by: Paul E. McKenney <[email protected]>
>
> diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> index 921daa7..edb7539 100644
> --- a/kernel/rcu/tree.c
> +++ b/kernel/rcu/tree.c
> @@ -2870,7 +2870,7 @@ void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
> // Probable double kfree_rcu(), just leak.
> WARN_ONCE(1, "%s(): Double-freed call. rcu_head %p\n",
> __func__, head);
> - return;
> + goto unlock_return;
> }
> head->func = func;
> head->next = krcp->head;
> @@ -2883,6 +2883,7 @@ void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
> schedule_delayed_work(&krcp->monitor_work, KFREE_DRAIN_JIFFIES);
> }
>
> +unlock_return:
> if (krcp->initialized)
> spin_unlock(&krcp->lock);
> local_irq_restore(flags);
On Thu, Sep 26, 2019 at 02:19:54PM -0400, Joel Fernandes wrote:
> On Tue, Sep 24, 2019 at 09:03:48AM -0700, Paul E. McKenney wrote:
> > On Tue, Sep 24, 2019 at 08:15:12AM -0400, Joel Fernandes wrote:
> > > On Tue, Sep 24, 2019 at 4:05 AM Dan Carpenter <[email protected]> wrote:
> > > >
> > > > tree: https://kernel.googlesource.com/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev.2019.09.23a
> > > > head: 97de53b94582c208ee239178b208b8e8b9472585
> > > > commit: 39676bb72323718a9e7bab1ba9c4a68319a96f62 [62/77] rcu: Add support for debug_objects debugging for kfree_rcu()
> > > >
> > > > If you fix the issue, kindly add following tag
> > > > Reported-by: kbuild test robot <[email protected]>
> > > > Reported-by: Dan Carpenter <[email protected]>
> > > >
> > > > smatch warnings:
> > > > kernel/rcu/tree.c:2882 kfree_call_rcu() warn: inconsistent returns 'irqsave:flags'.
> > > > Locked on: line 2867
> > > > Unlocked on: line 2882
> > > >
> > > > git remote add rcu https://kernel.googlesource.com/pub/scm/linux/kernel/git/paulmck/linux-rcu.git
> > > > git remote update rcu
> > > > git checkout 39676bb72323718a9e7bab1ba9c4a68319a96f62
> > > > vim +2882 kernel/rcu/tree.c
> > > >
> > > > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2850) void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
> > > > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2851) {
> > > > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2852) unsigned long flags;
> > > > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2853) struct kfree_rcu_cpu *krcp;
> > > > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2854)
> > > > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2855) head->func = func;
> > > > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2856)
> > > > 87970ccf5a9125 Paul E. McKenney 2019-09-19 2857 local_irq_save(flags); // For safely calling this_cpu_ptr().
> > > > ^^^^^^^^^^^^^^^^^^^^^
> > > > IRQs disabled.
> > > >
> > > > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2858) krcp = this_cpu_ptr(&krc);
> > > > ff8db005e371cb Paul E. McKenney 2019-09-19 2859 if (krcp->initialized)
> > > > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2860) spin_lock(&krcp->lock);
> > > > 5f5046cc15d514 Joel Fernandes (Google 2019-08-05 2861)
> > > > 87970ccf5a9125 Paul E. McKenney 2019-09-19 2862 // Queue the object but don't yet schedule the batch.
> > > > 39676bb7232371 Joel Fernandes (Google 2019-09-22 2863) if (debug_rcu_head_queue(head)) {
> > > > 39676bb7232371 Joel Fernandes (Google 2019-09-22 2864) // Probable double kfree_rcu(), just leak.
> > > > 39676bb7232371 Joel Fernandes (Google 2019-09-22 2865) WARN_ONCE(1, "%s(): Double-freed call. rcu_head %p\n",
> > > > 39676bb7232371 Joel Fernandes (Google 2019-09-22 2866) __func__, head);
> > > > 39676bb7232371 Joel Fernandes (Google 2019-09-22 2867) return;
> > > >
> > > > Need to re-enable before returning.
> > >
> > > Right. At this point the system has a bug anyway since it is a
> > > double-free. But yes, no reason to introduce more bugs. Will fix.
> > > Thank you, Dan!
> >
> > What Joel said!
> >
> > As long as I am doing several other reports anyway...
> >
> > How does the to-be-squashed patch below look?
>
> Hi Paul,
>
> Sorry for the late reply due to the conference..
>
> This patch looks Ok, the code in your tree though is slightly different mine
> I think because you reworked the kfree_rcu() code for working during early
> boot.
Yes, I did pull some of the changes earlier.
> After my talk tomorrow, I will go through your rcu/dev tree in detail to
> review the reworks you did in detail.
Sounds good, and best of everything with the talk!
> Let me know if you have the kfree_rcu() changes in a separate topic branch,
> as well. So it will make reviewing easier.
They will be, shortly after -rc1 comes out.
Thanx, Paul
> thanks,
>
> - Joel
>
>
> >
> > Thanx, Paul
> >
> > ------------------------------------------------------------------------
> >
> > commit 39af4c08038a8a6a7b1c9804fdd2c1921d583222
> > Author: Paul E. McKenney <[email protected]>
> > Date: Tue Sep 24 09:02:00 2019 -0700
> >
> > squash! rcu: Add support for debug_objects debugging for kfree_rcu()
> >
> > [ paulmck: Fix IRQ per kbuild test robot <[email protected]> feedback. ]
> > Signed-off-by: Paul E. McKenney <[email protected]>
> >
> > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> > index 921daa7..edb7539 100644
> > --- a/kernel/rcu/tree.c
> > +++ b/kernel/rcu/tree.c
> > @@ -2870,7 +2870,7 @@ void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
> > // Probable double kfree_rcu(), just leak.
> > WARN_ONCE(1, "%s(): Double-freed call. rcu_head %p\n",
> > __func__, head);
> > - return;
> > + goto unlock_return;
> > }
> > head->func = func;
> > head->next = krcp->head;
> > @@ -2883,6 +2883,7 @@ void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
> > schedule_delayed_work(&krcp->monitor_work, KFREE_DRAIN_JIFFIES);
> > }
> >
> > +unlock_return:
> > if (krcp->initialized)
> > spin_unlock(&krcp->lock);
> > local_irq_restore(flags);