CVE-2022-49929

In the Linux kernel, the following vulnerability has been resolved:

RDMA/rxe: Fix mr leak in RESPST_ERR_RNR

rxe_recheck_mr() will increase mr's ref_cnt, so we should call rxe_put(mr) to drop mr's ref_cnt in RESPST_ERR_RNR to avoid below warning:

WARNING: CPU: 0 PID: 4156 at drivers/infiniband/sw/rxe/rxe_pool.c:259 __rxe_cleanup+0x1df/0x240 [rdma_rxe] ... Call Trace: rxe_dereg_mr+0x4c/0x60 [rdma_rxe] ib_dereg_mr_user+0xa8/0x200 [ib_core] ib_mr_pool_destroy+0x77/0xb0 [ib_core] nvme_rdma_destroy_queue_ib+0x89/0x240 [nvme_rdma] nvme_rdma_free_queue+0x40/0x50 [nvme_rdma] nvme_rdma_teardown_io_queues.part.0+0xc3/0x120 [nvme_rdma] nvme_rdma_error_recovery_work+0x4d/0xf0 [nvme_rdma] process_one_work+0x582/0xa40 ? pwq_dec_nr_in_flight+0x100/0x100 ? rwlock_bug.part.0+0x60/0x60 worker_thread+0x2a9/0x700 ? process_one_work+0xa40/0xa40 kthread+0x168/0x1a0 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork+0x22/0x30

This patch fixes a memory leak (reference count imbalance) in the RXE RDMA responder path when a read reply packet fails to allocate memory (e.g., due to low resources). The function rxe_recheck_mr() increases the reference count of the Memory Region (MR), but in the RESPST_ERR_RNR error path, it failed to release it via rxe_put(mr). This led to a warning in __rxe_cleanup() and ultimately memory not being freed properly.

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