From e3ececfe668facd87d920b608349a32607060e66 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 4 Feb 2022 14:42:35 -0800 Subject: ref_tracker: implement use-after-free detection Whenever ref_tracker_dir_init() is called, mark the struct ref_tracker_dir as dead. Test the dead status from ref_tracker_alloc() and ref_tracker_free() This should detect buggy dev_put()/dev_hold() happening too late in netdevice dismantle process. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- lib/ref_tracker.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'lib') diff --git a/lib/ref_tracker.c b/lib/ref_tracker.c index a6789c0c626b..32ff6bd497f8 100644 --- a/lib/ref_tracker.c +++ b/lib/ref_tracker.c @@ -20,6 +20,7 @@ void ref_tracker_dir_exit(struct ref_tracker_dir *dir) unsigned long flags; bool leak = false; + dir->dead = true; spin_lock_irqsave(&dir->lock, flags); list_for_each_entry_safe(tracker, n, &dir->quarantine, head) { list_del(&tracker->head); @@ -72,6 +73,8 @@ int ref_tracker_alloc(struct ref_tracker_dir *dir, gfp_t gfp_mask = gfp; unsigned long flags; + WARN_ON_ONCE(dir->dead); + if (gfp & __GFP_DIRECT_RECLAIM) gfp_mask |= __GFP_NOFAIL; *trackerp = tracker = kzalloc(sizeof(*tracker), gfp_mask); @@ -100,6 +103,8 @@ int ref_tracker_free(struct ref_tracker_dir *dir, unsigned int nr_entries; unsigned long flags; + WARN_ON_ONCE(dir->dead); + if (!tracker) { refcount_dec(&dir->untracked); return -EEXIST; -- cgit v1.2.3