1 // SPDX-License-Identifier: GPL-2.0-or-later
2 #include <linux/export.h>
3 #include <linux/ref_tracker.h>
4 #include <linux/slab.h>
5 #include <linux/stacktrace.h>
6 #include <linux/stackdepot.h>
8 #define REF_TRACKER_STACK_ENTRIES 16
11 struct list_head head; /* anchor into dir->list or dir->quarantine */
13 depot_stack_handle_t alloc_stack_handle;
14 depot_stack_handle_t free_stack_handle;
17 void ref_tracker_dir_exit(struct ref_tracker_dir *dir)
19 struct ref_tracker *tracker, *n;
24 spin_lock_irqsave(&dir->lock, flags);
25 list_for_each_entry_safe(tracker, n, &dir->quarantine, head) {
26 list_del(&tracker->head);
28 dir->quarantine_avail++;
30 list_for_each_entry_safe(tracker, n, &dir->list, head) {
31 pr_err("leaked reference.\n");
32 if (tracker->alloc_stack_handle)
33 stack_depot_print(tracker->alloc_stack_handle);
35 list_del(&tracker->head);
38 spin_unlock_irqrestore(&dir->lock, flags);
40 WARN_ON_ONCE(refcount_read(&dir->untracked) != 1);
42 EXPORT_SYMBOL(ref_tracker_dir_exit);
44 void ref_tracker_dir_print(struct ref_tracker_dir *dir,
45 unsigned int display_limit)
47 struct ref_tracker *tracker;
51 spin_lock_irqsave(&dir->lock, flags);
52 list_for_each_entry(tracker, &dir->list, head) {
53 if (i < display_limit) {
54 pr_err("leaked reference.\n");
55 if (tracker->alloc_stack_handle)
56 stack_depot_print(tracker->alloc_stack_handle);
62 spin_unlock_irqrestore(&dir->lock, flags);
64 EXPORT_SYMBOL(ref_tracker_dir_print);
66 int ref_tracker_alloc(struct ref_tracker_dir *dir,
67 struct ref_tracker **trackerp,
70 unsigned long entries[REF_TRACKER_STACK_ENTRIES];
71 struct ref_tracker *tracker;
72 unsigned int nr_entries;
76 WARN_ON_ONCE(dir->dead);
78 if (gfp & __GFP_DIRECT_RECLAIM)
79 gfp_mask |= __GFP_NOFAIL;
80 *trackerp = tracker = kzalloc(sizeof(*tracker), gfp_mask);
81 if (unlikely(!tracker)) {
82 pr_err_once("memory allocation failure, unreliable refcount tracker.\n");
83 refcount_inc(&dir->untracked);
86 nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 1);
87 nr_entries = filter_irq_stacks(entries, nr_entries);
88 tracker->alloc_stack_handle = stack_depot_save(entries, nr_entries, gfp);
90 spin_lock_irqsave(&dir->lock, flags);
91 list_add(&tracker->head, &dir->list);
92 spin_unlock_irqrestore(&dir->lock, flags);
95 EXPORT_SYMBOL_GPL(ref_tracker_alloc);
97 int ref_tracker_free(struct ref_tracker_dir *dir,
98 struct ref_tracker **trackerp)
100 unsigned long entries[REF_TRACKER_STACK_ENTRIES];
101 struct ref_tracker *tracker = *trackerp;
102 depot_stack_handle_t stack_handle;
103 unsigned int nr_entries;
106 WARN_ON_ONCE(dir->dead);
109 refcount_dec(&dir->untracked);
112 nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 1);
113 nr_entries = filter_irq_stacks(entries, nr_entries);
114 stack_handle = stack_depot_save(entries, nr_entries, GFP_ATOMIC);
116 spin_lock_irqsave(&dir->lock, flags);
118 pr_err("reference already released.\n");
119 if (tracker->alloc_stack_handle) {
120 pr_err("allocated in:\n");
121 stack_depot_print(tracker->alloc_stack_handle);
123 if (tracker->free_stack_handle) {
124 pr_err("freed in:\n");
125 stack_depot_print(tracker->free_stack_handle);
127 spin_unlock_irqrestore(&dir->lock, flags);
131 tracker->dead = true;
133 tracker->free_stack_handle = stack_handle;
135 list_move_tail(&tracker->head, &dir->quarantine);
136 if (!dir->quarantine_avail) {
137 tracker = list_first_entry(&dir->quarantine, struct ref_tracker, head);
138 list_del(&tracker->head);
140 dir->quarantine_avail--;
143 spin_unlock_irqrestore(&dir->lock, flags);
148 EXPORT_SYMBOL_GPL(ref_tracker_free);