== task struck leaks == There are leaks from task struct from time to time where someone forgot to call put_task_struct() somewhere leading to leaks. For example,
https://lore.kernel.org/lkml/[email protected]/ It was such a pain to debug this kind of leaks at the moment, as all we could do was to audit the code by checking all new put_task_struct() and get_task_struct() call sites which is error-prone because there could be other new call sites like get_pid_task() which would also need to be balanced with put_task_struct() as well. What do you think about adding some aux call traces for kmemleak in general? For example, if the tracking object is a task struct, it would save call traces for the first and last call of both get_task_struct() and put_task_struct(). Then, it could be expanded to track other refcount-based leaks in the future. == call_rcu() leaks == Another issue that might be relevant is that it seems sometimes, kmemleak will give a lot of false positives (hundreds) because the memory was supposed to be freed by call_rcu() (for example, in dst_release()) but for some reasons, it takes a long time probably waiting for grace periods or some kind of RCU self-stall, but the memory had already became an orphan. I am not sure how we are going to resolve this properly until we have to figure out why call_rcu() is taking so long to finish? Another solution is to add aux call traces for both skb_dst_drop() and skb_dst_set() for this case, but that there are many places to free memory via call_rcu() like inode free etc.
