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locking/lockdep: Make zap_class() remove all matching lock order entries

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Make sure that all lock order entries that refer to a class are removed
from the list_entries[] array when a kernel module is unloaded.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: johannes.berg@intel.com
Cc: tj@kernel.org
Link: https://lkml.kernel.org/r/20190214230058.196511-7-bvanassche@acm.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Bart Van Assche 2019-02-14 15:00:41 -08:00 committed by Ingo Molnar
parent 09329d1c20
commit 86cffb80a5
2 changed files with 14 additions and 6 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

1
include/linux/lockdep.h
View file

@ -178,6 +178,7 @@ static inline void lockdep_copy_map(struct lockdep_map *to,
struct lock_list {
struct list_head entry;
struct lock_class *class;
struct lock_class *links_to;
struct stack_trace trace;
int distance;

19
kernel/locking/lockdep.c
View file

@ -859,7 +859,8 @@ static struct lock_list *alloc_list_entry(void)
/*
* Add a new dependency to the head of the list:
*/
static int add_lock_to_list(struct lock_class *this, struct list_head *head,
static int add_lock_to_list(struct lock_class *this,
struct lock_class *links_to, struct list_head *head,
unsigned long ip, int distance,
struct stack_trace *trace)
{
@ -873,6 +874,7 @@ static int add_lock_to_list(struct lock_class *this, struct list_head *head,
return 0;
entry->class = this;
entry->links_to = links_to;
entry->distance = distance;
entry->trace = *trace;
/*
@ -1907,14 +1909,14 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev,
* Ok, all validations passed, add the new lock
* to the previous lock's dependency list:
*/
ret = add_lock_to_list(hlock_class(next),
ret = add_lock_to_list(hlock_class(next), hlock_class(prev),
&hlock_class(prev)->locks_after,
next->acquire_ip, distance, trace);
if (!ret)
return 0;
ret = add_lock_to_list(hlock_class(prev),
ret = add_lock_to_list(hlock_class(prev), hlock_class(next),
&hlock_class(next)->locks_before,
next->acquire_ip, distance, trace);
if (!ret)
@ -4107,15 +4109,20 @@ void lockdep_reset(void)
*/
static void zap_class(struct lock_class *class)
{
struct lock_list *entry;
int i;
/*
* Remove all dependencies this lock is
* involved in:
*/
for (i = 0; i < nr_list_entries; i++) {
if (list_entries[i].class == class)
list_del_rcu(&list_entries[i].entry);
for (i = 0, entry = list_entries; i < nr_list_entries; i++, entry++) {
if (entry->class != class && entry->links_to != class)
continue;
list_del_rcu(&entry->entry);
/* Clear .class and .links_to to avoid double removal. */
WRITE_ONCE(entry->class, NULL);
WRITE_ONCE(entry->links_to, NULL);
}
/*
* Unhash the class and remove it from the all_lock_classes list: