[rcu:dev.2019.09.23a 62/77] kernel/rcu/tree.c:2882 kfree_call_rcu() warn: inconsistent returns 'irqsave:flags'.
From: Dan Carpenter
Date: Tue Sep 24 2019 - 04:05:28 EST
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 <lkp@xxxxxxxxx>
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
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);
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