On Tue, 18 Jun 2024 09:42:35 -0700 Paul E. McKenney wrote: > > FTR, with mptcp self-tests we hit a few kmemleak false positive on RCU > > freed pointers, that where addressed by to this patch: > > > > commit 5f98fd034ca6fd1ab8c91a3488968a0e9caaabf6 > > Author: Catalin Marinas <catalin.marinas@xxxxxxx> > > Date: Sat Sep 30 17:46:56 2023 +0000 > > > > rcu: kmemleak: Ignore kmemleak false positives when RCU-freeing objects > > > > I'm wondering if this is hitting something similar? Possibly due to > > lazy RCU callbacks invoked after MSECS_MIN_AGE??? Dmitry mentioned this commit, too, but we use the same config for MPTCP tests, and while we repro TCP AO failures quite frequently, mptcp doesn't seem to have failed once. > Fun! ;-) > > This commit handles memory passed to kfree_rcu() and friends, but > not memory passed to call_rcu() and friends. Of course, call_rcu() > does not necessarily know the full extent of the memory passed to it, > for example, if passed a linked list, call_rcu() will know only about > the head of that list. > > There are similar challenges with synchronize_rcu() and friends. To be clear I think Dmitry was suspecting kfree_rcu(), he mentioned call_rcu() as something he was expecting to have a similar issue but it in fact appeared immune.
