Commit | Line | Data |
---|---|---|
4e66934e ED |
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> | |
7 | ||
8 | #define REF_TRACKER_STACK_ENTRIES 16 | |
9 | ||
10 | struct ref_tracker { | |
11 | struct list_head head; /* anchor into dir->list or dir->quarantine */ | |
12 | bool dead; | |
13 | depot_stack_handle_t alloc_stack_handle; | |
14 | depot_stack_handle_t free_stack_handle; | |
15 | }; | |
16 | ||
17 | void ref_tracker_dir_exit(struct ref_tracker_dir *dir) | |
18 | { | |
19 | struct ref_tracker *tracker, *n; | |
20 | unsigned long flags; | |
21 | bool leak = false; | |
22 | ||
e3ececfe | 23 | dir->dead = true; |
4e66934e ED |
24 | spin_lock_irqsave(&dir->lock, flags); |
25 | list_for_each_entry_safe(tracker, n, &dir->quarantine, head) { | |
26 | list_del(&tracker->head); | |
27 | kfree(tracker); | |
28 | dir->quarantine_avail++; | |
29 | } | |
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); | |
34 | leak = true; | |
35 | list_del(&tracker->head); | |
36 | kfree(tracker); | |
37 | } | |
38 | spin_unlock_irqrestore(&dir->lock, flags); | |
39 | WARN_ON_ONCE(leak); | |
40 | WARN_ON_ONCE(refcount_read(&dir->untracked) != 1); | |
8fd5522f | 41 | WARN_ON_ONCE(refcount_read(&dir->no_tracker) != 1); |
4e66934e ED |
42 | } |
43 | EXPORT_SYMBOL(ref_tracker_dir_exit); | |
44 | ||
45 | void ref_tracker_dir_print(struct ref_tracker_dir *dir, | |
46 | unsigned int display_limit) | |
47 | { | |
48 | struct ref_tracker *tracker; | |
49 | unsigned long flags; | |
50 | unsigned int i = 0; | |
51 | ||
52 | spin_lock_irqsave(&dir->lock, flags); | |
53 | list_for_each_entry(tracker, &dir->list, head) { | |
54 | if (i < display_limit) { | |
55 | pr_err("leaked reference.\n"); | |
56 | if (tracker->alloc_stack_handle) | |
57 | stack_depot_print(tracker->alloc_stack_handle); | |
58 | i++; | |
59 | } else { | |
60 | break; | |
61 | } | |
62 | } | |
63 | spin_unlock_irqrestore(&dir->lock, flags); | |
64 | } | |
65 | EXPORT_SYMBOL(ref_tracker_dir_print); | |
66 | ||
67 | int ref_tracker_alloc(struct ref_tracker_dir *dir, | |
68 | struct ref_tracker **trackerp, | |
69 | gfp_t gfp) | |
70 | { | |
71 | unsigned long entries[REF_TRACKER_STACK_ENTRIES]; | |
72 | struct ref_tracker *tracker; | |
73 | unsigned int nr_entries; | |
c12837d1 | 74 | gfp_t gfp_mask = gfp; |
4e66934e ED |
75 | unsigned long flags; |
76 | ||
e3ececfe ED |
77 | WARN_ON_ONCE(dir->dead); |
78 | ||
8fd5522f ED |
79 | if (!trackerp) { |
80 | refcount_inc(&dir->no_tracker); | |
81 | return 0; | |
82 | } | |
c12837d1 ED |
83 | if (gfp & __GFP_DIRECT_RECLAIM) |
84 | gfp_mask |= __GFP_NOFAIL; | |
85 | *trackerp = tracker = kzalloc(sizeof(*tracker), gfp_mask); | |
4e66934e ED |
86 | if (unlikely(!tracker)) { |
87 | pr_err_once("memory allocation failure, unreliable refcount tracker.\n"); | |
88 | refcount_inc(&dir->untracked); | |
89 | return -ENOMEM; | |
90 | } | |
91 | nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 1); | |
4e66934e ED |
92 | tracker->alloc_stack_handle = stack_depot_save(entries, nr_entries, gfp); |
93 | ||
94 | spin_lock_irqsave(&dir->lock, flags); | |
95 | list_add(&tracker->head, &dir->list); | |
96 | spin_unlock_irqrestore(&dir->lock, flags); | |
97 | return 0; | |
98 | } | |
99 | EXPORT_SYMBOL_GPL(ref_tracker_alloc); | |
100 | ||
101 | int ref_tracker_free(struct ref_tracker_dir *dir, | |
102 | struct ref_tracker **trackerp) | |
103 | { | |
104 | unsigned long entries[REF_TRACKER_STACK_ENTRIES]; | |
4e66934e | 105 | depot_stack_handle_t stack_handle; |
8fd5522f | 106 | struct ref_tracker *tracker; |
4e66934e ED |
107 | unsigned int nr_entries; |
108 | unsigned long flags; | |
109 | ||
e3ececfe ED |
110 | WARN_ON_ONCE(dir->dead); |
111 | ||
8fd5522f ED |
112 | if (!trackerp) { |
113 | refcount_dec(&dir->no_tracker); | |
114 | return 0; | |
115 | } | |
116 | tracker = *trackerp; | |
4e66934e ED |
117 | if (!tracker) { |
118 | refcount_dec(&dir->untracked); | |
119 | return -EEXIST; | |
120 | } | |
121 | nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 1); | |
4e66934e ED |
122 | stack_handle = stack_depot_save(entries, nr_entries, GFP_ATOMIC); |
123 | ||
124 | spin_lock_irqsave(&dir->lock, flags); | |
125 | if (tracker->dead) { | |
126 | pr_err("reference already released.\n"); | |
127 | if (tracker->alloc_stack_handle) { | |
128 | pr_err("allocated in:\n"); | |
129 | stack_depot_print(tracker->alloc_stack_handle); | |
130 | } | |
131 | if (tracker->free_stack_handle) { | |
132 | pr_err("freed in:\n"); | |
133 | stack_depot_print(tracker->free_stack_handle); | |
134 | } | |
135 | spin_unlock_irqrestore(&dir->lock, flags); | |
136 | WARN_ON_ONCE(1); | |
137 | return -EINVAL; | |
138 | } | |
139 | tracker->dead = true; | |
140 | ||
141 | tracker->free_stack_handle = stack_handle; | |
142 | ||
143 | list_move_tail(&tracker->head, &dir->quarantine); | |
144 | if (!dir->quarantine_avail) { | |
145 | tracker = list_first_entry(&dir->quarantine, struct ref_tracker, head); | |
146 | list_del(&tracker->head); | |
147 | } else { | |
148 | dir->quarantine_avail--; | |
149 | tracker = NULL; | |
150 | } | |
151 | spin_unlock_irqrestore(&dir->lock, flags); | |
152 | ||
153 | kfree(tracker); | |
154 | return 0; | |
155 | } | |
156 | EXPORT_SYMBOL_GPL(ref_tracker_free); |