In the Linux kernel, the following vulnerability has been resolved:
dlm: fix add msg handle in send_queue ordered
In a benchmark scenario triggering a lot of requests that triggers a lot of DLM messages on the network it can be that the mh->seq is not ordered according the oldest seq number. This ordering is required by dlm_receive_ack as before(mh->seq, seq) will stop to check for older sequence numbers that are ordered in the tail of node->send_queue.
The side effects of not having it correct ordered regarding before(mh->seq, seq) are refcounting issues and use-after free.
I only was able to reproduce this issue in a experimental DLM branch and a user space DLM benchmark that uses io_uring. After changing this I dont experienced any refcounting with the sending buffer issues anymore.
References
- https://git.kernel.org/stable/c/4d45250b1d22960f86d83245be188b16e456218b
- https://git.kernel.org/stable/c/6369619f1b665f12d8c99cc6ff733c64eb08b22e
- https://git.kernel.org/stable/c/712714f818d83373847874ab0f8e426be79296cf
- https://git.kernel.org/stable/c/ae9e534e502a0f48c12baf83608c5de0ff0eab11
- https://git.kernel.org/stable/c/d2248cb70c070f8f04762872772e155b59016f17