144 строки
3.9 KiB
C
144 строки
3.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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#include <linux/export.h>
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#include <linux/ref_tracker.h>
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#include <linux/slab.h>
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#include <linux/stacktrace.h>
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#include <linux/stackdepot.h>
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#define REF_TRACKER_STACK_ENTRIES 16
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struct ref_tracker {
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struct list_head head; /* anchor into dir->list or dir->quarantine */
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bool dead;
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depot_stack_handle_t alloc_stack_handle;
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depot_stack_handle_t free_stack_handle;
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};
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void ref_tracker_dir_exit(struct ref_tracker_dir *dir)
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{
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struct ref_tracker *tracker, *n;
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unsigned long flags;
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bool leak = false;
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spin_lock_irqsave(&dir->lock, flags);
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list_for_each_entry_safe(tracker, n, &dir->quarantine, head) {
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list_del(&tracker->head);
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kfree(tracker);
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dir->quarantine_avail++;
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}
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list_for_each_entry_safe(tracker, n, &dir->list, head) {
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pr_err("leaked reference.\n");
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if (tracker->alloc_stack_handle)
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stack_depot_print(tracker->alloc_stack_handle);
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leak = true;
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list_del(&tracker->head);
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kfree(tracker);
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}
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spin_unlock_irqrestore(&dir->lock, flags);
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WARN_ON_ONCE(leak);
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WARN_ON_ONCE(refcount_read(&dir->untracked) != 1);
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}
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EXPORT_SYMBOL(ref_tracker_dir_exit);
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void ref_tracker_dir_print(struct ref_tracker_dir *dir,
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unsigned int display_limit)
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{
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struct ref_tracker *tracker;
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unsigned long flags;
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unsigned int i = 0;
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spin_lock_irqsave(&dir->lock, flags);
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list_for_each_entry(tracker, &dir->list, head) {
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if (i < display_limit) {
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pr_err("leaked reference.\n");
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if (tracker->alloc_stack_handle)
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stack_depot_print(tracker->alloc_stack_handle);
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i++;
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} else {
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break;
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}
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}
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spin_unlock_irqrestore(&dir->lock, flags);
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}
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EXPORT_SYMBOL(ref_tracker_dir_print);
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int ref_tracker_alloc(struct ref_tracker_dir *dir,
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struct ref_tracker **trackerp,
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gfp_t gfp)
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{
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unsigned long entries[REF_TRACKER_STACK_ENTRIES];
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struct ref_tracker *tracker;
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unsigned int nr_entries;
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gfp_t gfp_mask = gfp;
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unsigned long flags;
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if (gfp & __GFP_DIRECT_RECLAIM)
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gfp_mask |= __GFP_NOFAIL;
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*trackerp = tracker = kzalloc(sizeof(*tracker), gfp_mask);
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if (unlikely(!tracker)) {
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pr_err_once("memory allocation failure, unreliable refcount tracker.\n");
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refcount_inc(&dir->untracked);
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return -ENOMEM;
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}
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nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 1);
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nr_entries = filter_irq_stacks(entries, nr_entries);
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tracker->alloc_stack_handle = stack_depot_save(entries, nr_entries, gfp);
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spin_lock_irqsave(&dir->lock, flags);
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list_add(&tracker->head, &dir->list);
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spin_unlock_irqrestore(&dir->lock, flags);
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return 0;
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}
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EXPORT_SYMBOL_GPL(ref_tracker_alloc);
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int ref_tracker_free(struct ref_tracker_dir *dir,
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struct ref_tracker **trackerp)
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{
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unsigned long entries[REF_TRACKER_STACK_ENTRIES];
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struct ref_tracker *tracker = *trackerp;
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depot_stack_handle_t stack_handle;
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unsigned int nr_entries;
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unsigned long flags;
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if (!tracker) {
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refcount_dec(&dir->untracked);
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return -EEXIST;
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}
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nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 1);
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nr_entries = filter_irq_stacks(entries, nr_entries);
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stack_handle = stack_depot_save(entries, nr_entries, GFP_ATOMIC);
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spin_lock_irqsave(&dir->lock, flags);
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if (tracker->dead) {
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pr_err("reference already released.\n");
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if (tracker->alloc_stack_handle) {
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pr_err("allocated in:\n");
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stack_depot_print(tracker->alloc_stack_handle);
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}
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if (tracker->free_stack_handle) {
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pr_err("freed in:\n");
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stack_depot_print(tracker->free_stack_handle);
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}
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spin_unlock_irqrestore(&dir->lock, flags);
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WARN_ON_ONCE(1);
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return -EINVAL;
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}
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tracker->dead = true;
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tracker->free_stack_handle = stack_handle;
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list_move_tail(&tracker->head, &dir->quarantine);
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if (!dir->quarantine_avail) {
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tracker = list_first_entry(&dir->quarantine, struct ref_tracker, head);
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list_del(&tracker->head);
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} else {
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dir->quarantine_avail--;
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tracker = NULL;
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}
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spin_unlock_irqrestore(&dir->lock, flags);
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kfree(tracker);
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return 0;
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}
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EXPORT_SYMBOL_GPL(ref_tracker_free);
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